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Vehicle emissions are recognized as a primary source of particle-phase polycyclic aromatic hydrocarbons (PAHs), significant contributors to the hazardous properties of PM 2.5 . This study investigates the profiles of PAHs through measurements conducted in a tunnel and an urban roadside environment in 2020. We quantified real-world vehicle emission factors for mixed fleets in the Zhongshu tunnel in Guizhou, southwest China, and found that the total PAHs had an emission factor of 8.15 μg veh -1 km -1 , with higher factors observed for high-ring PAHs. Additionally, we analyzed concentrations of 15 PAHs at a roadside environment in Hefei, southern China, with an average concentration of 23.81 ng/m 3 . PAHs with 4, 5, and 6 rings comprised 80% of total PAHs at the roadside and 87% in the tunnel. Gasoline emissions were the predominant source in both the tunnel and roadside environments, supplemented by non-tailpipe emissions, catering, domestic cooking, and asphalt from road surfaces. Notably, while the total toxicity equivalent concentration of Benzo[a]pyrene (BaP) significantly exceeded the World Health Organization (WHO) guidelines of 1 ng/m 3 , the presence of additional compounds such as Dibenzo[a,h]anthracene (DahA) markedly increased the toxicological impact of PM 2.5 from vehicle emissions. Therefore, it is essential to implement targeted pollution control strategies in central urban areas that address not only the overall concentration of PAHs but also their specific toxic contributions Continuous monitoring and assessment of PAHs in the urban environment are indispensable for effectively reducing their health impacts., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Ammonia emissions from gasoline vehicles have been confirmed an essential precursor of urban secondary aerosols. To more comprehensively understand the formation mechanisms and better control vehicle-related ammonia, this paper measured the on-road ammonia emissions from six conventional and four hybrid vehicles using a state-of-the-art Quantum Cascade Laser analyzer on urban, rural, and highway routes. The test vehicles emitted 0.01-4.27 mg/km of ammonia emissions, with a fleet average of 1.04 mg/km. Compared to the previous laboratory tests, the results of this study were low because of the high emission standards of the vehicles and the near-zero emissions during rural driving. Most test vehicles showed high ammonia emissions during engine warm-up, while some vehicles also had ammonia peaks during dynamic highway driving. On average, hybrid vehicles emitted 60.7% less ammonia emissions than the conventional candidates. It is confirmed that ammonia was formed when incomplete oxidation products presented on a warm catalyst. Engine warm-up, dynamic highway driving, particulate filter regeneration, and hybrid engine re-starting could be important sources. It is hypothesized that the ammonia formed on the upstream catalyst could be consumed by the downstream catalyst at moderate catalyst temperature, resulting in the near-zero ammonia emissions during rural driving., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The emission factors and characteristics of pollutants from river vessels are critical for understanding the environmental impact of ship emissions, particularly in inland waterways. However, research gaps remain regarding emissions of volatile organic compounds (VOCs) and intermediate-volatility organic compounds (IVOCs) from river vessels. In this study, we collected and analyzed organic vapor emissions, including non-methane hydrocarbon (NMHCs), oxygenated volatile organic compounds (OVOCs) and IVOCs, from three river vessels under different operating conditions. The results show that the average emission factors of NMHCs, and IVOCs from river vessels are significantly higher than those from ocean-going vessels. Inland waterways' proximity to residential areas increases the risk of pollutant transport to urban environments, heightening the importance of managing river vessel emissions. Notably, older auxiliary engines displayed higher organic vapor emissions compared to main engines, underscoring the need for better control measures for aging engines. By analyzing the emission characteristics of organic vapors from river vessels, it was found that, unlike other pollution sources where C12 n-alkanes are the major contributors of IVOCs, the contributions of C12-C15 n-alkanes in river vessel exhaust are similar, with C14 n-alkane having the highest contribution. OVOCs constituted more than 50% to ozone formation potentials of organic vapors, while IVOCs were responsible for over 90% of the secondary organic aerosol (SOA) formation. Given these findings, targeted efforts to reduce OVOCs and IVOCs emissions from river vessels should prioritized to mitigate their environmental impact., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Current research on building carbon emissions primarily focuses on various carbon emission assessment models and the use of life cycle analysis to evaluate overall building carbon emissions, with limited attention given to excavation engineering. Based on the life cycle method and process analysis, this study analyzes carbon emissions in excavation engineering by optimizing the evaluation model for fuel consumption standards of freight vehicles during the transportation phase in China. To account for the difference between actual and rated fuel consumption of transport vehicles, factors such as road conditions, traffic congestion, and temperature are introduced to adjust the carbon emission calculation model for the transportation phase. This approach reasonably incorporates the impact of fuel consumption during vehicle idling on carbon emission calculations. Using the 02B excavation of the Beijing Sub-Center Station transportation hub as a case study to validate the proposed method, the analysis reveals that the primary source of carbon emissions in excavation engineering is earthwork transportation, accounting for 40.50% of total emissions. Among these, earthwork transportation contributes 95.28% of emissions within the transportation phase. Due to adjustments in the carbon emission calculation model for the transportation phase, carbon emissions increased by 1,226.79 tons, accounting for 9.2% of the total. The revised model provides a theoretical basis for accurately assessing carbon emissions in excavation engineering., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Chongxi, Zhang. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Lebanon, plagued by political and economic crises, experienced a government collapse in early 2020, leading to an electrical nationwide blackout by 2023. Diesel generators were used to compensate for the absence of power production from the national provider, Electricité du Liban (EDL). To investigate the effect of the crisis on the levels of 16 EPA particle bound polycyclic aromatic hydrocarbons (PPAHs), an annual comparative analysis of three locations within Beirut started in 2022 and ended in 2023. The locations are: American University of Beirut (AUB), Beirut Central District (BCD) and Nursing School Makassed University (NSMU). Sampling took place and the PPAHs samples were extracted, quantified using Gas Chromatography-Mass spectrometry (GC-MS) and source apportioned using Positive Matrix Factorization (PMF). Particulate Matter 2.5μm (PM2.5) mean levels at AUB, BCD and NSMU, which was found to be 14.3 μg/m3, 18.3 μg/m3 and 22.6 μg/m3 respectively, beside the high annual PM2.5 mean level (17.19 μg/m3) exceeded the World Health Organization (WHO) standard levels. The factors identified in the three sites are diesel, incineration, and gasoline emissions. The dominant factor in three sites was the diesel emissions, specifically from generators, with 56% in BCD, 42% in AUB and 43% in NSMU. The contribution of diesel emission in AUB has increased by 100% since the last study in 2016-2017. Similarly, the excess cancer risk (ESR) in the three sites was above the EPA threshold with an increase of 53% compared to the one calculated previously in AUB. This situation, where law of enforcement is absent, need for international action to curb emissions and for funding agencies to adopt sustainable, "carbon-free" funding strategies to support urban development in low- and middle-income countries (LMICs). Yet, EDL's failure to fulfill Lebanon's populace electricity requirements infringes upon their electricity entitlements., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Al Hallak et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

One of the main causes of air pollution, particularly in large cities, is vehicles due to it continued use of hydrocarbon fuels. The understanding of nonlinear interactions of vehicle parameters uncovers more realistic relationships for enhancing formulation of strategies to address vehicle-related pollution. Thus, the study aims to evaluate the interaction and quadratic effect of vehicle parameters on Hydrocarbon (HC), Carbon dioxide (CO2), Carbon monoxide (CO), and Nitrogen oxide (NOx) emissions. The SV-5Q Vehicle Exhaust Gas Analyzer was used to collect emission concentrations data from one thousand and two (1002) light-duty petrol vehicles at three (3) government-accredited vehicle inspection sites in Accra, Ghana. Pollution control devices, maintenance frequency, and vehicle age were also collected. The linear regression analysis revealed that vehicle age showed a positive linear relationship with CO emissions. Maintenance frequency, on the other hand, demonstrated a negative linear relationship with both CO and HC emissions. The interaction between vehicle age and maintenance frequency positively impacted CO and HC emissions, while the interaction between vehicle age and emission technology had a negative effect on CO. Additionally, the combined effect of frequency of maintenance and emission technology significantly reduced CO emissions but increased HC emissions. Notably, the quadratic effect of vehicle age positively influenced CO emissions. Similarly, CO, HC, and NOx emissions were positively correlated with the squared effect of emission technology. Stricter emissions standards, encouraging frequent maintenance and testing of vehicular exhaust emissions, and doing away with over-aged vehicles are recommended to control and reduce vehicular exhaust emissions., Competing Interests: The authors declared that no competing interest exist., (Copyright: © 2024 Milku et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Road-Deposited Sediments (RDS) samples were collected from four different roads in Beijing, and the distribution of pollutants in RDS with various particle sizes was compared. In this study, the cumulative mass of RDS exhibited a positive correlation with the number of dry days, and the RDS load below 75 μm was also influenced by road traffic volume. As traffic volume escalated, there was a corresponding increase in the load of these smaller RDS. Most pollutants accumulated within RDS with sizes below 150 μm, rendering them the primary contributors to the pollution. In terms of the antecedent dry-weather days, fifteen days emerged as a potentially pivotal point, with both the rate of pollutant accumulation and the contribution of pollution sources to RDS having stabilized after this duration. The origins of pollutants in roads of different functional areas exhibited certain disparities. The pollutants on major roads with high traffic volume were attributed to frequent vehicular activities. The pollutants on residential roads stemmed from soil particles and fallen leaves in the roadside green belts as well as from human activities. And the pollutants on urban-rural crossroad might be attributed to the industrial contamination with factories located on one side., Competing Interests: Declarations. Conflict of interest: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

To investigate the pollution characteristics of polycyclic aromatic hydrocarbons (PAHs) indoors and outdoors and their influencing factors, PM 2.5 samples were systematically collected from both environments in Jinan during the summer and autumn seasons. During the observation period, the concentration of ∑ 19PAHs was 18.57 ± 10.50 ng/m 3 indoors and 23.79 ± 16.13 ng/m 3 outdoors. Most PAHs exhibited indoor-to-outdoor (I/O) ratios less than 1, indicating that indoor PAHs were primarily derived from the infiltration of outdoor sources. Correlation analysis underscored the significant influence of temperature on both outdoor concentrations and I/O ratios of PAHs. By utilizing diagnostic ratios and principal component analysis (PCA), vehicle emissions were identified as the predominant source of outdoor PAHs. Our study found that the toxic equivalents of benzo[a]pyrene (TEQ BaP ) values exceeded the European Commission's standard of 1 ng/m 3 , with indoor values at 2.78 ng/m 3 and outdoor values at 3.57 ng/m 3 . Moreover, the total incremental lifetime cancer risk (ILCR Total ) associated with exposure to PM 2.5 -bound PAHs surpassed the acceptable level of 10E-6, indicating potential adverse health effects. These results underscore the urgent necessity for more stringent regulatory measures to reduce PAH emissions. Additionally, our findings provide valuable insights into how environmental factors shape the relationship between indoor and outdoor PAHs., Competing Interests: Xinfeng Wang is an Academic Editor for PeerJ., (©2024 Gao et al.)

Vehicle emissions are a major source of greenhouse gases globally. Dual selective catalytic reduction (SCR), an advanced version of single SCR, is crucial under stricter nitrogen oxide (NO x ) emission standards for heavy-duty diesel vehicles (HDDVs). However, the emission characteristics of nitrous oxide (N 2 O), a byproduct of SCR and a potent greenhouse gas, remain unclear. This study investigates the N 2 O emissions from HDDVs equipped with single or dual SCR systems using heavy-duty chassis dynamometers under various ambient temperatures, altitudes, and loading masses. The results showed that the brake-specific emissions (EF b ) of N 2 O from HDDVs with single and dual SCRs were 76.28-269.65 mg/kWh and 147.50-170.22 mg/kWh, respectively. Notably, the dual SCR-equipped HDDV emitted 6-22 times more N 2 O than NO x under all tested conditions. As ambient temperature increased from -10 °C to 25 °C and from 25 °C to 40 °C, the average distance-based emission factors (EF d ) of N 2 O for the single SCR-equipped HDDV increased by 87.73% and 48.26%, respectively. However, the variation was not significant for the dual SCR-equipped HDDV. Under half- and full-load conditions, the average EF d of N 2 O for the single SCR-equipped HDDV increased by 47.57% and 110.92%, respectively, compared to those without loading. Similarly, N 2 O emissions for dual SCR-equipped HDDV increased by 41.40% and 65.37% under the same loading variations. As altitude increased from 0 m to 3000 m, the average EF d of N 2 O for the single SCR-equipped HDDV decreased by 64.31%. Additionally, N 2 O emissions were significantly affected by SCR temperature, engine power, and nitric oxide (NO)/nitrogen dioxide (NO 2 ) ratio. These findings are crucial for setting future greenhouse gas limits of HDDVs and informing carbon reduction strategies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Ambient fine particulate matter (PM 2.5 ) can catalyze the generation of reactive oxygen species in vivo, causing hazardous effects on human health. Molecular-level analysis of major oxidative potential (OP) active species is still limited. In this study, we used non-targeted high-resolution mass spectrometry to analyze the water-soluble organic components of ambient PM 2.5 samples in winter and summer. Chemical components and back trajectory analysis revealed significant impacts of biomass burning and ship emissions on PM 2.5 in winter and summer, respectively. Significance Analysis of the Microarray method and correlation analyses were combined to identify OP (OP DTT and OP OH ) active species in characteristic organic compounds emitted from ship and biomass combustion emissions and to explore possible mechanisms. The results showed that the characteristic compounds emitted from ship were mainly organic amine compounds and contained more sulfur-containing components, while the characteristic compounds emitted from biomass burning were mainly oxygen-containing aromatic compounds of CHO and CHON groups. The high toxicity of summer PM 2.5 might derive from reduced organic nitrogen compounds (C 6 H 14 N 2 O 3 S, C 6 H 12 N 2 O 3 S, C 10 H 9 N 3 O, C 6 H 9 N 5 O 3 S, and C 6 H 14 N 4 O) emission from ship sources. These reduced organic nitrogen compounds can form complexes with metals, affecting their solubility and reactivity in aerosols. Phenolic hydroxyl compounds were the main contributors to the PM 2.5 OP from biomass burning in winter. Semiquinone radicals produced by oxidation of phenolic compounds can further promote the generation of reactive oxygen species through Fenton-like reactions. Our studies based on ambient PM 2.5 samples further deepened the understanding of the molecular level of organic compounds emitted from ships and biomass burning, and their association with OP., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Little is known about how childhood exposure to traffic-related air pollution (TRAP) and stress interact to affect adults' cardiometabolic health. We examined this interaction and assessed the impact of over 10 years of childhood TRAP exposure on cardiometabolic health., Methods: From 2018 to 2023, 313 young adults from the Southern California Children's Health Study were enrolled in a follow-up assessment. Using CALINE4 line source dispersion model, average childhood TRAP exposures (from pregnancy to age 13) were estimated for nitrogen oxides (NO x ) from all roads. Traffic density was calculated within a 300-m residential buffer. Cardiometabolic health was assessed in adulthood (mean age 24 ± 1.7) based on blood lipids (total cholesterol, high- and low-density lipoprotein [HDL, LDL], triglycerides), glucose metabolism (fasting glucose, fasting insulin, HbA1c), body composition (BMI, android/gynoid ratio [AG ratio], percent body fat), and blood pressure. A PDAY (Pathobiologic Determinants of Atherosclerosis in Youth) score was generated to evaluate overall cardiometabolic health. Participants' perceived stress was assessed in childhood and adulthood (ages 13 and 24 years, respectively)., Results: Results of mixed effects linear models, adjusted for demographics and smoking status, suggested that each standard deviation increase in childhood exposure to traffic-related total NO x was associated with 0.62 increase in PDAY score (95% Confidence Interval [CI]:0.10,1.14), 0.09% increase in HbA1c (95%CI: 0.04, 0.15), 1.19% increase in percent body fat (95%CI: 0.18, 2.20), and 0.96 kg/m 2 increase in BMI (0.11, 1.80) in adulthood. Among participants with higher childhood stress levels, we observed significant associations of traffic-related total NO x with total cholesterol, HDL, LDL, HbA1c, insulin, and BMI. None of these associations were significant among people with lower stress levels. We observed similar statistically significant associations of traffic density., Conclusion: Long-term childhood exposure to TRAP in childhood may have lasting adverse impacts on cardiometabolic health, especially for children with higher stress levels., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Shohreh Farzan reports financial support was provided by National Institutes of Health. Breton, Bastain, Habre reports financial support was provided by National Institutes of Health. Shohreh Farzan reports a relationship with University of Southern California that includes: employment. Guo, Habre, Xu, Chen, Howland, Gauderman, Bastain, Breton reports a relationship with University of Southern California that includes: employment. Lurmann, Pavlovic reports a relationship with Sonoma Technology Inc that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Concerns over the ecological impacts of urban road runoff have increased, partly due to recent research into the harmful impacts of tire particles and their chemical leachates. This study aimed to help the community of researchers, regulators and policy advisers in scoping out the priority areas for further study. To improve our understanding of these issues an interdisciplinary, international network consisting of experts (United Kingdom, Norway, United States, Australia, South Korea, Finland, Austria, China and Canada) was formed. We synthesised the current state of the knowledge and highlighted priority research areas for tire particles (in their different forms) and their leachates. Ten priority research questions with high importance were identified under four themes (environmental presence and detection; chemicals of concern; biotic impacts; mitigation and regulation). The priority research questions include the importance of increasing the understanding of the fate and transport of these contaminants; better alignment of toxicity studies; obtaining the holistic understanding of the impacts; and risks they pose across different ecosystem services. These issues have to be addressed globally for a sustainable solution. We highlight how the establishment of the intergovernmental science-policy panel on chemicals, waste, and pollution prevention could further address these issues on a global level through coordinated knowledge transfer of car tire research and regulation. We hope that the outputs from this research paper will reduce scientific uncertainty in assessing and managing environmental risks from TP and their leachates and aid any potential future policy and regulatory development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Indirect greenhouse gases (GHGs) play a key role in modulating both regional and global atmospheric chemistry and act as air pollutants that degrade air quality. The rising number of premature deaths and notable health hazards could be linked to increasing concentration of these air pollutants in the atmosphere. As a developing nation, India is often regarded as one of the most polluting countries due to increasing anthropogenic activities. Therefore, identifying the sources of these indirect GHGs gases such as CO, NO x , VOC and SO 2 and quantifying their emissions has become a critical requirement for understanding regional atmospheric chemistry. In this study, we developed a comprehensive, technology-driven gridded emission inventory for India at a high resolution (0.1°×0.1°) for the base year 2020. Using the IPCC bottom-up approach, the study estimated the total emissions of CO (45 Tg/yr), NO x (22.8 Tg/yr), VOC (10.8 Tg/yr) and SO 2 (15.1 Tg/yr) from all the dominating sources. Vehicle exhaust contributes the most NO x and VOC whereas the residential and power sectors are the highest emitters of CO and SO 2 , respectively. This newly reported surface emission data would be an essential tool for policymakers in formulating mitigation strategies and will also serve as a vital input for atmospheric chemistry and climate studies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

To synthesize vast amounts of high-throughput biological information, omics-fields like epigenetics have applied risk scores to develop biomarkers for environmental exposures. Extending the risk score analytic tool to the metabolomic data would be highly beneficial. This research aimed to develop and evaluate metabolomic risk score (metRS) approaches reflecting the biological response to traffic-related air pollution (TRAP) exposure (fine particulate matter, black carbon, and nitrogen dioxide). A simulation study compared three metRS methodologies: elastic net regression, which uses penalized regression to select metabolites, and two variations of thresholding, where a p-value cutoff is used to select metabolites. The methods performance was compared to assess 1) ability to correctly select metabolites associated with daily TRAP and 2) ability of the risk score to predict daily TRAP exposure. Power calculations and false discovery rates (FDR) were calculated for each approach. This metRS was applied to two real cohorts, the Center for Health Discovery and Wellbeing (CHDWB, n = 180) and Environment and Reproductive Health (EARTH, n = 200). In simulations, elastic net regression consistently presented inflated FDR for both high and low effect sizes and across all three sample sizes (n = 200; 500; 1000). Power to detect correct metabolites exceeded 0.8 for all three sample sizes in all three methods. In the real data application assessing associations of metabolomics risk scores and TRAP, associations were largely null. While we did not identify strong associations between the risk scores and TRAP in the real data application, metabolites selected by the risk score approaches were enriched in pathways that are well-known for their association with TRAP. These results demonstrate that certain methodologies to construct metabolomics risk scores are statistically robust and valid; however, standardized metabolic profiling and large sample sizes are required., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Diesel vehicle exhaust is one of the major contributors to ultrafine particles (UFPs) in urban areas in China. However, there is still a lack of knowledge about UFPs emission characteristics from current in-use diesel vehicles. This study has carried out an on-road test of 10 in-use Light-duty Diesel Trucks (LDDTs) with different emission control standards in China using a self-established portable measurement system based on the Electronic Low-pressure Impactor (ELPI) and characterized the ultrafine particle number (PN) concentration, particle size distribution and metal element contents. The results revealed a significant reduction of 93.37% in the average PN 0.1 emission factor of LDDTs from China III to China VI. Notably, LDDTs compliant with the China VI vehicle emission control standard exhibited the lowest PN 0.1 and PM 0.1 emission factors, measuring 4.991 × 10 14 #/km and 0.627 g/km, respectively. By taking into account emissions under real driving conditions, we found that the PN emission rates grow with the increase of the Vehicle Specific Power (VSP). The cold-start phase had higher PN emissions than the hot-start phase, with 8590, 1890, 477, and 22 times higher than those of the ambient air (1.18 × 10 5 #/cm 3 ), respectively. The installation of Diesel Particulate Filter (DPF) can decrease UFPs by more than 99.8%, while the PN emission factor during the DPF regeneration stage (1.85 × 10 16 #/km) increased by 5 orders of magnitude that of the DPF normal works (7.51 × 10 11 #/km). Metal element contents analysis shows that Fe, Ca, Al and Mg are the dominant elements in UFPs of LDDT exhaust gas, but the element of Ni is slightly increasing in a China VI, possibly due to the new automotive engine exhaust manifolds being made of Ni instead of cast iron for the purpose of having more high-temperature resistance. Our study demonstrates the importance of monitoring and routine maintenance of exhaust after-treatment systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Motor vehicles emit most Malaysian PAHs in particulate matter of 2.5 μm (PM2.5-bound PAHs). Although traffic-related air pollution harms healthy people, there is a knowledge gap regarding PAHs' effects on Malaysians. This study examines PM2.5-bound PAH concentrations, distribution, sources, and health risks in Malaysia's high and low-traffic zones. Kuala Lumpur (KL) and Hulu Langat (HL) exhibit Malaysia's high- and low-traffic areas. The high-volume air sampler collected 40 ambient PM2.5 samples at both locations. Solid-phase extraction and gas chromatography-mass spectrometry (GC-MS) assessed PAHs. The mean PM2.5-bound PAH concentrations in KL (5.85 ng m-3) were significantly higher than in HL (0.55 ng m-3) (p<0.001). KL has nine times more low-molecular-weight PAHs (LMW-PAHs) (2.63 vs. 0.27 ng m-3) and eleven times more high-molecular-weight PAHs (HMW-PAHs) (3.22 vs. 0.28 ng m-3) than HL. Over 51% of PM2.5 air samples at both sites included HMW-PAHs. Source apportionment tools (Diagnostic ratio, positive matrix factorization, and principal component analysis) showed that fossil fuel combustions (petrol and diesel) produced the greatest PAHs in both locations. Moreover, PAH exposure impinged higher carcinogenic health risks in KL than in HL. In conclusion, traffic and automobile pollution account for the short- and long-term health risks posed by PAHs in both regions., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Al-Battawi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

This study uses mobile monitoring to gain a better understanding of particulate matter (PM) sources in two areas of Central and Outer London, UK. We find that, unlike emissions of nitrogen oxides (NO + NO 2 = NO x ), which are elevated in Central London due to the high number of diesel vehicles and congestion, fine particulate matter (PM 2.5 ) emissions are well-controlled. This finding provides evidence for the effectiveness of vehicle particulate filters, supporting the view that their widespread adoption has mitigated PM 2.5 emissions, even in the highly dieselized area of Central London. However, mobile monitoring also reveals infrequent elevated PM 2.5 concentrations caused by malfunctioning vehicles. These events were confirmed through simultaneous measurements of PM 2.5 and sulfur dioxide (SO 2 ), the latter being a strong tracer of engine lubricant combustion. A single event from a gasoline car, representing just 0.15% of the driving distance in Outer London, was responsible for 7.4% of the ΔPM 2.5 concentration above background levels, highlighting the ongoing importance of addressing high-emission vehicles. In a novel application of mobile monitoring, we demonstrate the ability to identify and quantify non-vehicular sources of PM. Among the sources unambiguously identified are construction activities, which result in elevated concentrations of coarse particulate matter (PM coarse = PM 10 - PM 2.5 ). The mobile measurements clearly highlight the spatial extent of the influence of such sources, which would otherwise be difficult to determine. Furthermore, these sources are shown to be weather-dependent, with PM coarse concentrations reduced by 62.1% during wet conditions compared to dry ones.

Air pollution constitutes a significant worldwide environmental challenge, presenting threats to both our well-being and the purity of our food supply. This study suggests employing Recurrent Neural Network (RNN) models featuring Long Short-Term Memory (LSTM) units for forecasting PM10 particle levels in multiple locations in Skopje simultaneously over a time span of 1, 6, 12, and 24 hours. Historical air quality measurement data were gathered from various local sensors positioned at different sites in Skopje, along with data on meteorological conditions from publicly available APIs. Various implementations and hyperparameters of several deep learning models were compared. Additionally, an analysis was conducted to assess the influence of urban traffic on air and noise pollution, leveraging the COVID-19 lockdown periods when traffic was virtually non-existent. The outcomes suggest that the proposed models can effectively predict air pollution. From the urban traffic perspective, the findings indicate that car traffic is not the major contributing factor to air pollution., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Kostadinov et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Globally, the transport sector is a major contributor to air pollution. Currently, in the UK, vehicle emissions contribute significant amounts of nitrogen oxide (NOx) and particulate matter (PM) pollution in urban areas. Low-emission-zone policies have been used as an intervention to tackle air pollution, and in this context, the UK launched the Low-Traffic Neighbourhood scheme. This study investigates the impacts of the Low-Traffic Neighbourhood in Kings Heath, Birmingham, UK, to evaluate its impact in reducing air pollution and local community perspectives about the scheme and perceived impacts on health and well-being. This study employs a mixed-method approach comprising an air-quality-monitoring assessment and a survey questionnaire involving 210 residents. The findings reveal an increase in active travel and a reduction in air pollution levels in the years after the implementation of the scheme, although the area is still non-compliant with the 2021 WHO air quality guidelines. Nonetheless, the scheme has a polarising effect and created a division within the local community about the overall scheme acceptance and spatial distribution of the scheme's benefits. This study underscores the importance of comprehensive baseline data, long-term community engagement, and integration with broader urban planning initiatives to enhance the success of future Low-Neighbourhood Traffic schemes.

"Prevent minor issues before they become major problems, and prepare for the future." This study utilizes complex system theory to introduce a nonlinear dynamic system for examining the production and emission reduction strategies of new energy vehicle (NEV) and gasoline vehicle (GV) manufacturers under the dual credit (DC) policy over a long-term game process. By considering production delays, we analyze dynamic behaviors within a duopoly automotive system, including stable regions, bifurcation, chaotic attractors, and the Largest Lyapunov exponent (LLE). The results show that: (1) As production and carbon emission adjustment parameters increase, the decision-making system for both automakers can slip into disorder, posing a risk of disruption within the automotive industry. (2) In stable regions, GVs' carbon emission adjustments do not affect the production of either NEVs or GVs, while NEVs demonstrate greater flexibility in production adjustments compared to GVs. (3) The industry system will likely benefit from delay production decisions that could help stabilize the automobile market. The study provides theoretical support for the smooth transformation of old and new driving forces in the automobile industry., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Tang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

P-phenylenediamines (PPDs) and a quinone derivative (6PPD-Q), as antioxidants added to tires, can inevitably enter into the environment during tire wear emission, posing potential health and ecological risks. However, investigation on their pollution characteristics in PM 2.5 is still lacking, especially for high-pollution scenarios, such as tunnels. Herein, we investigated the pollution characteristics and emission factors, as well as the correlation analysis and daily intakes of PM 2.5 -bound PPDs and 6PPD-Q in tunnel. The results indicated heavy PPDs and 6PPD-Q pollution were observed in tunnel PM 2.5 , with the concentration at the two tunnel sites being 3.83 and 8.73 times higher than those at the urban site, respectively. PPDs were negatively correlated to relative humidity and positively to temperature. Emission factors of 6PPD and 6PPD-Q were 3013.54 and 1466.67 ng·veh -1 ·km -1 for large vehicles. PPDs and 6PPD-Q were most harmful to children, and annual exposure dosages at the tunnel sites were 4.64 times higher than those at the urban site. This study conducted a comparison of PPDs and 6PPD-Q in urban and tunnel environments for the first time. Our findings clarified the key factors to reduce the pollution of PPDs in tunnel and supported policy-making for emission reduction of PPDs and 6PPD-Q., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The health risks of particulate matters (PMs) associated with their chemical components and sizes have attracted increasing attention. However, the toxic effect of critical toxic components in size-segregated PMs from specific emission source remains unclear. We present the toxicity of size-segregated elements in PMs via integrating toxic analysis and online single-particle measurements of real-world industrial plants, vehicles, and road dust. The number fractions of elemental carbon (EC)- and Fe-containing particles were 5-11 and 3-12 folds greater than those of other metal-containing particles, respectively. A unimodal distribution with the peak at 0.4 µm was observed for the toxic metals emitted from industrial plants and road dust, while the distribution was relatively flat for vehicles. When integrating the abundance with toxicity of metals, especially Mn, Cu, V, and Fe, the peak for PM toxicity occurred at 0.4 µm for road dust, 0.4-0.7 µm for industrial plants, and 0.8 µm for vehicle-emitted PM. The inhalation risk in the alveolar region increased for these source-emitted PMs due to the efficient deposition of toxic PMs within 0.4-0.8 µm. These results reveal the complex coupling of health risks and size distributions of PMs, and further highlight that the health-oriented control of air pollution should consider PM 1 ., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study investigated the spatial distribution and chemical characteristics of potentially toxic elements (PTEs) in road-deposited sediments (RDS) at the Port of Busan by size fraction. Enrichment factor (EF) values for Zn, Cd, and Sb in fine RDS <250 μm were 52-69, 49-78, and 46-44, respectively, indicating 'extremely high enrichment'. Various statistical analyses, including PCA and PMF models, revealed a strong correlation between pollution levels in RDS <250 μm and vehicle type, identifying non-exhaust emissions (NEE) of vehicles as a primary source of PTEs in RDS from the port. The risk index (RI) value of fine RDS ranged from 649 to 2238, indicating that the entire study area could be classified as having a 'significant ecological risk,' with higher values observed in heavy-duty vehicles (HDV) areas. The study underscores the need for effective NEE management to mitigate the environmental impact of ports on marine ecosystems., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Jin Young Choi, Jae Seong Lee, Kyung-Tae Kim, Geun-Ha Park, Jun-Mo Jung, Kongtae Ra, Sangmin Hyun Chang Eon Lee reports financial support was provided by Korea Institute of Ocean Science and Technology. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

This research evaluated the emission characteristics of old ships during typical operations, under varying cruising speeds, and during lock transit, using a shaft power meter and PEMS. The research revealed that upstream and downstream low-load voyages accounted for 67.9 % and 65.4 % of the total voyage, respectively. The average emission factors of CO, NO X and CO 2 were highest under lock transit with 17.13±0.51 g/kWh, 16.2±0.62 g/kWh and 1075.37±5.72 g/kWh, respectively, while SO 2 was highest under manoeuvring with 0.46 ± 0.001 g/kWh. Emissions are closely correlated with engine speed, with the largest emissions at cruising, and emissions at departure and docking significantly concentrated in the 10-15 % and 5-10 % loads. This research emphasizes the importance of considering low-load operating conditions in engine test cycles and provides data support for maritime decarbonization and emission reduction strategies. Future research should continue to explore the emission characteristics of old ships., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this study., (Copyright © 2024. Published by Elsevier Ltd.)

The COVID-19 pandemic and the International Maritime Organization's (IMO) 2020 fuel-switching policy have profoundly impacted global maritime activities, leading to unprecedented changes in shipping emissions. This study aimed to examine the effects from different scales and investigate the underlying drivers. The big data model Ship Emission Inventory Model (SEIM) was updated and applied to analyze the spatiotemporal pattern of global ship emissions as well as the main contributors in 2019 and 2020. Overall, ships emitted NO x , CO, HC, CO 2 , and N 2 O declined by 7.4 %-13.8 %, while SO 2 , PM 2.5 , and BC declined by 40.9 %-81.9 % in 2020 compared with 2019. The decline in CO 2 emissions indicated a comparable reduction across vessel tonnages. Ship emissions occurring at cruising status accounted for over 90 % of the ship's CO 2 emission reduction. Container ships, chemical tankers, and Ro-Ro vessels were the primary contributors to the emission reductions, with container ships alone responsible for 39.4 % of the CO 2 decrease. The ship's CO 2 emissions variations revealed the decline-rebound patterns in response to the pandemic. Asian-related routes saw emissions drop in February 2020, followed by a rebound in May, while European and American routes experienced declines starting in May, with a recovery in August. Further analysis of CO 2 emission in Exclusive Economic Zones (EEZs) showed high temporal consistency between vessel CO 2 emissions, sailing speeds, and international trade volumes across continents, and exhibited heterogeneity in main contributing ship type of emission reduction on continental scale. Our study reveals the short-term fluctuation characteristics of global ship emissions during the pandemic, particularly focusing on their spatiotemporal evolution and the inherent disparities. The results highlight the correlation between global ship emissions and trade, as well as the operational status of ships, and their rigidity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Alcohol fuels with different carbon numbers such as propanol (C3), butanol (C4) and pentanol (C5) have lately become popular in both conventionally and RCCI-operated diesel engines thanks to their high cetane number (CN) and oxygen content along with lower latent heat of evaporation, which are useful for reducing the high CO/HC emissions, whereas RCCI mode still suffers from these emissions. Therefore, in this study, these three alcohol fuels with carbon numbers ranging from C3 to C5 were employed as low-reactivity fuel (LRF) in a single-cylinder RCCI engine under a constant engine speed of 2400 rpm and varying loadings (from 20 to 60% of full load at 20% intervals) and premixed ratios (from 0 to 60% with 15% intervals) when using B7 as high-reactivity fuel (HRF). In the experimental study, the effect of oxygen content, latent heat of evaporation, and cetane number which changes linearly with the carbon number of alcohols used, on exhaust emissions, were analyzed. When compared to conventional diesel mode (CDM), RCCI mode using alcohol fuels increased HC and CO emissions but decreased smoke opacity at a great level. The greatest reduction in both CO emissions and smoke opacity was recorded with the use of propanol which has the highest oxygen content, while pentanol with the lowest latent heat of evaporation had success in reducing HC emissions. In addition, NOx emissions were reduced by up to 60% when butanol was used as low-reactivity fuel. Ignition delay increased more during RCCI operation with propanol having an octane number of 118, whereas butanol and pentanol have 92 and 78, respectively. It was concluded that the properties of alcohol fuels such as the oxygen content and latent heat of evaporation had a significant effect on HC/CO emissions in RCCI engines., Competing Interests: Declarations. Ethical approval: Not applicable. Consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The global searchlight for sustainable alternative fuels to reduce emissions produced from the combustion of fossil fuels illuminates biofuels owing to their matching properties with fossil fuels. This is the impetus for this study which systematically examines the impact of neem biodiesel (NB) blends with pure diesel on the physical and chemical properties of particulate matter (PM) from diesel engines. Pure diesel (B0) and four fuel blends, namely, B5, B10, B15 and B20 are examined. The impact of NB blends on the physical and chemical properties of PM is studied using a single-cylinder, 4-stroke diesel engine. The PM captured directly from the diesel engine at two standard engine speeds is analyzed by physical microscopy techniques and chemical analyses. Comparing the results of gaseous emissions for B0 with those of B20, it is found that B20 decreases CO by 9.6% and 19.3% at low and high engine speeds, respectively, but increases NO X . Regarding PM emission, in comparison to B0, B20 decreases particle sizes from 59.4 ± 8.5 nm to 42.8 ± 4.2 nm and 63.3 ± 8.1 nm to 43.7 ± 5.2 nm; opacities from 15.9% to 9.3% and 21.1%-11.4%; carbon contents from 66.53% to 44.53% and 72.53%-61.99%; and total carbon concentrations (total organic carbon and total inorganic carbon) from 3.6120 mg/L to 1.8435 mg/L and 2.5970 mg/L to 1.6002 mg/L at low and high engine speeds, respectively. Furthermore, B20 increases the unused oxygen content from 14.07% to 21.47% and 16.82%-18.42%; oxygen reactivity from 1.80 ± 0.08 to 2.75 ± 0.18 and 1.10 ± 0.20 to 1.35 ± 0.06; and volatile substances by 68.4% and 57.1% at low and high engine speeds, respectively. This study demonstrates that NB could be a potential alternative fuel for diesel engines regarding PM emissions, where B20 blend has the highest impact on PM properties, but it needs additional NOx mitigation strategies., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Prof. Pak Kin Wong reports financial support was provided by University of Macau. Prof. Pak Kin Wong reports a relationship with University of Macau that includes: employment and funding grants. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Evidence suggests that long-term exposure to air pollution may increase the risk of dementia and related cognitive outcomes. A major source of air pollution is automotive traffic, which is modifiable by technological and regulatory interventions., Objectives: We examined associations of four traffic-related air pollutants with rates of cognitive decline in a cohort of older adults., Methods: We analyzed data from the Chicago Health and Aging Project (CHAP), a longitudinal (1993-2012) community-based cohort study of older adults that included repeated assessments of participants' cognitive performance. Leveraging previously developed air pollution models, we predicted participant-level exposures to the tailpipe pollutants oxides of nitrogen ( NO X ) and nitrogen dioxide ( NO 2 ), plus the nontailpipe pollutants copper and zinc found in coarse particulate matter [PM with aerodynamic diameter 2.5 μ m to 10 μ m ( PM 2.5 - 10 , Cu ) and PM 2.5 - 10 , Zn , respectively], over the 3 y prior to each participant's baseline assessment. Using generalized estimating equations, we estimated covariate-adjusted associations of each pollutant with rates of cognitive decline. We probed the robustness of our results via several sensitivity analyses, including alterations to the length of the exposure assessment window and exploring the influence of pre- and post-baseline selection bias., Results: Using data from 6,061 participants, estimated associations of these pollutant exposures with cognitive decline were largely inconsistent with large adverse effects. For example, a standard deviation ( 5.8  ppb ) increment in NO X corresponded to a slightly slower rate of cognitive decline [e.g., mean difference in change in global score, 0.010 standard unit/5 y, 95% confidence interval (CI): -0 .016 , 0.036]. The results of most of our sensitivity analyses were in generally similar to those of our main analyses, but our prebaseline selection bias results suggest that our analytic results may have been influenced by differential survivorship into our study sample., Discussion: In this large prospective cohort study, we did not observe compelling evidence that long-term TRAP exposure is associated with cognitive decline. https://doi.org/10.1289/EHP14585.

There is a body of evidence that ultrafine particles (UFP, those with diameters ≤ 100 nm) might have significant impacts on health. Accordingly, identifying sources of UFP is essential to develop abatement policies. This study focuses on urban Europe, and aims at identifying sources and quantifying their contributions to particle number size distribution (PNSD) using receptor modelling (Positive Matrix Factorization, PMF), and evaluating long-term trends of these source contributions using the non-parametric Theil-Sen's method. Datasets evaluated include 14 urban background (UB), 5 traffic (TR), 4 suburban background (SUB), and 1 regional background (RB) sites, covering 18 European and 1 USA cities, over the period, when available, from 2009 to 2019. Ten factors were identified (4 road traffic factors, photonucleation, urban background, domestic heating, 2 regional factors and long-distance transport), with road traffic being the primary contributor at all UB and TR sites (56-95 %), and photonucleation being also significant in many cities. The trends analyses showed a notable decrease in traffic-related UFP ambient concentrations, with statistically significant decreasing trends for the total traffic-related factors of -5.40 and -2.15 % yr -1 for the TR and UB sites, respectively. This abatement is most probably due to the implementation of European emissions standards, particularly after the introduction of diesel particle filters (DPFs) in 2011. However, DPFs do not retain nucleated particles generated during the dilution of diesel exhaust semi-volatile organic compounds (SVOCs). Trends in photonucleation were more diverse, influenced by a reduction in the condensation sink potential facilitating new particle formation (NPF) or by a decrease in the emissions of UFP precursors. The decrease of primary PM emissions and precursors of UFP also contributed to the reduction of urban and regional background sources., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Maritime transportation has significantly contributed to global economic development but is also a major source of air pollution. This study aims to provide an inverse calculation framework of vessel emission source intensity for emission monitoring. This research enhanced the traditional Gaussian diffusion model by specific characteristics of ship emissions and various influencing factors identified through simulation experiments. An inverse model is developed using pattern search and particle swarm optimization (PSO) algorithms to estimate marine exhaust source strengths. Results indicate that the PSO algorithm is the most accurate and efficient, especially with an iteration step size of 0.1 s. Practical application using data from 86 monitored ships revealed that 76 had fuel sulfur content exceeding the 0.1 % threshold, achieving an accuracy rate of 88.37 %. These findings are crucial for improving the understanding of marine exhaust dispersion and advancing remote monitoring technologies, contributing to better environmental management of maritime transport emissions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Many climate mitigation policies to reduce transportation emissions have public health benefits related to ambient air pollution. However, few health analyses consider the equity implications of alternative policies. Equity can be conceptualized in many different ways that may be relevant to communities, decision-makers, and other stakeholders., Objectives: To evaluate alternative transportation emissions reduction scenarios across the northeastern United States considering population exposure reductions and multiple equity constructs., Methods: We developed four quantitative indicators reflecting equity constructs that aligned with stakeholder perspectives, including racial/ethnic exposure inequities, proportion of benefits in environmental justice communities, distribution of benefits among participating states, and rural/urban share of benefits. We analyzed numerous transportation emissions reduction scenarios for directly emitted fine particulate matter (primary PM 2.5 ) covering 12 Northeast states and the District of Columbia. We used the Community Multiscale Air Quality model with the decoupled direct method to estimate the reduction in population-weighted primary PM 2.5 exposure and the impact on equity for each scenario., Results: Scenarios that yielded greater reductions in population-weighted primary PM 2.5 exposure generally emphasized emissions reductions in urban areas or states with large urban centers, with a more than threefold difference in benefits across scenarios. The higher exposure-benefit scenarios typically also had greater reductions in racial/ethnic exposure inequities but led to higher between-state or rural/urban inequality. Scenarios that targeted uniform percentage emission reductions from light or heavy-duty trucks best addressed rural/urban inequalities but led to the smallest reductions in racial/ethnic inequity., Conclusion: There are intrinsic tradeoffs among equity constructs, where focusing resources on distributing benefits across states or between urban and rural populations could come at the expense of less reduction in racial/ethnic exposure inequities or in environmental justice communities. Future health benefits analyses should incorporate multiple equity indicators that reflect different stakeholder perspectives and articulate the underlying constructs and tradeoffs., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Laura Buckley reports financial support was provided by Barr Foundation. Laura Buckley reports financial support was provided by Energy Foundation. Calvin A. Arter, Christopher Rick, Patrick L. Kinney, Sarav Arunachalam, Jonathan J. Buonocore, Jonathan I. Levy reports financial support was provided by Barr Foundation. Calvin A. Arter, Christopher Rick, Patrick L. Kinney, Sarav Arunachalam, Jonathan J. Buonocore, Jonathan I. Levy reports financial support was provided by Energy Foundation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Arctic miners face significant risks from diesel exhaust and dust exposure, potentially leading to adverse respiratory health. Employers must limit harmful exposures, using personal protective equipment (PPE) as a last line of defense. This study explored the association between reported respiratory exposure and symptoms, and PPE training and usage. Data from the MineHealth study (2012-2014) included a total of 453 Arctic open pit miners in Norway, Sweden, and Finland. Participants answered questions on exposure to dust and diesel exhaust, respiratory symptoms, and PPE use, in addition to age, gender, BMI, smoking, and self-rated health. Estimated exposure to dust was common, reported by 91%, 80%, and 82% and that of diesel exhaust by 84%, 43%, and 47% of workers in Sweden, Finland, and Norway, respectively. Reported dust exposure was significantly related to respiratory symptoms (OR 2.2, 95% CI 1.3-3.7), diesel exposure increased the occurrence of wheezing (OR 2.6, 95% CI 1.3-5.4). PPE use varied between the studied mines. Non-use was common and related to reduced visibility, wetness, skin irritation and fogging of the respiratory PPE. Future research should employ more precise exposure assessment, respiratory function as well as explore the reasons behind the non-compliance of PPE use.

This study aimed to assess the characteristics of particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) from various stationary and mobile emission sources in Taiwan, with a focus on source apportionment and associated health risks. The northern power plant, equipped with bag filters operating at 150 °C, had significantly lower FPM and CPM levels (0.44 and 0.13 mg/m 3 , respectively) compared to the central and southern power plants, which used electrostatic precipitators operating at 250 °C (FPM, 1.45-8.35 mg/m 3 ; CPM, 2.37-3.73 mg/m 3 ). Additionally, emissions from diesel vehicles under both idle and high-speed conditions exhibited higher FPM levels (3.46-4.67 mg/m 3 ) than gasoline vehicles (0.19-0.40 mg/m 3 ). In terms of PAH toxicity, diesel vehicle emissions had significantly higher BaP-TEQ (87.3 ng/m 3 ) and BaP-MEQ (25.9 ng/m 3 ) levels compared to power plants (BaP-TEQ, 5.49 ng/m 3 ; BaP-MEQ, 2.65 ng/m 3 ). The highest ambient concentrations of PM2.5, BaP-TEQ, and BaP-MEQ were recorded at traffic sites, with values of 48 ± 36 µg/m 3 , 0.29 ng/m 3 , and 0.11 ng/m 3 , respectively. Differences in PAH distributions between stationary and mobile sources were influenced by factors such as pollution control technologies, combustion temperatures, and fuel types. Diesel vehicle emissions were dominated by benzo[g,h,i]perylene (BghiP), indeno[1,2,3-cd]pyrene (IND), benzo[a]pyrene (BaP), and benzo[b]fluoranthene (BbF) under idle conditions, while phenanthrene (PA), pyrene (Pyr), and BghiP were prevalent under high-speed conditions. Source apportionment conducted using principal component analysis (PCA) and positive matrix factorization (PMF) identified diesel and gasoline vehicles as the dominant contributors to atmospheric PAHs in Taiwan, accounting for 38% of the total, followed by coal-fired power plants at 35%. The highest lifetime excess cancer risk (ECR) of 2.5 × 10⁻ 5 was observed in traffic-dense areas, emphasizing the public health implications of vehicle emissions. The study adds credibility to the source apportionment findings, and the health risk analysis highlights variations across different regions, including traffic, urban, rural, and background zones., Competing Interests: Declarations. Ethical approval: Not applicable. Consent to participate: All authors contributed to this work. Consent for publication: All authors have approved authorship, read, and consented to publication. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Macro-scale distribution of air pollution concentrations is influenced by factors including geography, weather, industry, transport and regulation. Pollution sources are unevenly distributed, with some communities disproportionately impacted by higher emissions. This study separates the effects of deprivation from ethnicity as factors that influence proximity to pollution sources. We combine recent decadal census data (2021) on socioeconomic deprivation and detailed population ethnicity at fine scales (Lower Super Output layer Area, LSOA n = 1600 people) with a 1×1 km sector-resolved atmospheric emissions inventory for NO x and primary PM 2.5 in England. All 24 minoritised ethnic groups studied experienced higher average local NO x and PM 2.5 emissions than socio-economically matched populations in the majority 'White: English, Welsh, Scottish, Northern Irish or British' ethnic group. Chinese, Arab and Bangladeshi communities experienced the largest disparity in NO x , with weighted emissions 100%, 91%, 89% higher than white populations of matched deprivation status. Bangladeshi, Pakistani and Roma groups experienced on average 40%, 40%, 36% higher PM 2.5 emissions locally than matched white groups. For NO x the largest contributors leading to disparity, were road transport (48%), domestic combustion (23%) and industry (15%). For PM 2.5 the greatest contributors to disparity were domestic combustion (53%), road transport (19%), and industry (11%). Living near to road transport and in city centres are frequently cited as primary drivers of ethnicity and deprivation-based disparities, however the analysis identifies that industrial, domestic and off-road sources create issues of the same magnitude, and disparities remain in suburban settings, smaller towns and some rural areas., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Nathan Gray, Ally Lewis and Sarah Moller report financial support was provided by United Kingdom Department for Environment Food and Rural Affairs. Ally Lewis and Sarah Moller report a relationship with DEFRA Air Quality Expert Group that includes: consulting or advisory. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This research presents an in-depth examination that utilizes a hybrid technique consisting of response surface methodology (RSM) for experimental design, analysis of variance (ANOVA) for model development, and the artificial bee colony (ABC) algorithm for multi-objective optimization. The study aims to enhance engine performance and reduce emissions through the integration of global maxima for brake thermal efficiency (BTE) and global minima for brake-specific fuel consumption (BSFC), hydrocarbon (HC), nitrogen oxides (NOx), and carbon monoxide (CO) emissions into a composite objective function. The relative importance of each objective was determined using weighted combinations. The ABC algorithm effectively explored the parameter space, determining the optimum values for brake mean effective pressure (BMEP) and 1-decanol% in the fuel mix. The results showed that the optimized solution, with a BMEP of 4.91 and a 1-decanol % of 9.82, improved engine performance and cut emissions significantly. Notably, the BSFC was reduced to 0.29 kg/kWh, demonstrating energy efficiency. CO emissions were lowered to 0.598 vol.%, NOx emissions to 1509.91 ppm, and HC emissions to 29.52 vol.%. Furthermore, the optimizing procedure produced an astounding brake thermal efficiency (BTE) of 28.78%, indicating better thermal energy efficiency within the engine. The ABC algorithm enhanced engine performance and lowered emissions overall, highlighting the advantageous trade-offs made by a weighted mix of objectives. The study's findings contribute to more sustainable combustion engine practises by providing crucial insights for upgrading engines with higher efficiency and fewer emissions, thus furthering renewable energy aspirations., Competing Interests: Declarations. Ethical approval: The research presented in this manuscript has been conducted in compliance with ethical principles and guidelines. The study did not involve any human subjects. Consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: Air pollution and traffic noise are detrimental to cardiovascular health. However, the effects of different sources of these exposures on cardiovascular biomarkers remain unclear. We explored the associations of long-term exposure to source-specific air pollution (vehicular exhausts and residential woodsmoke) at low concentrations and road-traffic noise with systemic inflammation and cardiovascular disease biomarkers., Material and Methods: Modeled outdoor exposure to fine particulate matter (aerodynamic diameter ≤2.5 μm; PM 2.5 ) from vehicular exhausts and residential woodsmoke, nitrogen dioxide (NO 2 ) from road traffic, and road-traffic noise were linked to the home addresses of the participants (Finnish residents aged 25-74) in the FINRISK study 1997-2012. The participants were located in the cities of Helsinki, Vantaa, and the region of Turku, Finland. The outcomes were high-sensitivity C-reactive protein (CRP), a biomarker for systemic inflammation, and cardiovascular disease biomarkers N-terminal pro-B-type natriuretic peptide (NT-proBNP) and troponin I. We performed cross-sectional analyses with linear and additive models and adjusted for potential confounders., Results: We found no association between PM 2.5 from vehicular exhausts (% CRP difference for 1 μg/m 3 increase in PM 2.5 : -0.9, 95% confidence interval, CI: -7.2, 5.8), or from residential woodsmoke (% difference: -8.1, 95% CI: -21.7, 7.9) and CRP (N = 4147). Road-traffic noise >70 dB tended to be positively associated with CRP (% CRP difference versus noise reference category of ≤45 dB: 18.3, 95% CI: -0.5, 40.6), but the association lacked significance and robustness (N = 7142). Otherwise, we found no association between road-traffic noise and CRP, nor between NO 2 from road traffic and NT-proBNP (N = 1907) or troponin I (N = 1951)., Conclusion: Long-term exposures to source-specific, fairly low-level air pollution from vehicular exhausts and residential woodsmoke, or road-traffic noise were not associated with systemic inflammation and cardiovascular disease biomarkers in this urban area., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Tanja Zeller has patent #397 WO2022043229A1 licensed to a computing device to estimate the probability of myocardial infarction. Tanja Zeller is shareholder of the ART.EMIS GmbH Hamburg. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

This study investigated the sources and distribution characteristics of PM 2.5 and its chemical components (ions, carbons, elements) at five locations within the Banwal and Sihwa National Industrial Complexes in Ansan and Siheung. These large-scale industrial clusters, comprising 7642 businesses across sectors such as petrochemicals, steel, machinery, and electronics, operate throughout the year. From 2020 to 2023, the average PM 2.5 concentration in the study area was 28.66 ± 16.72 μg/m 3 , with notable seasonal differences observed across the five measurement points. Ionic components were the primary contributors to PM 2.5 , while carbon and trace element concentrations fluctuated with the seasons. The coefficient of divergence (COD) analysis indicated that emission source differences between sites were insignificant, with COD values consistently below the threshold of 0.3. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) identified secondary aerosols and vehicle emissions as the main sources of PM 2.5 , alongside additional contributions from Asian dust, industrial emissions, road dust, coal combustion, metal processing, biomass burning, and soil dust. These results highlight the need for systematic and economical air pollution control strategies in complex industrial areas, using COD to identify source differences and quantify contributions at different sites., Competing Interests: Declarations. Ethical approval: Not applicable. Consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Environmental CO presents a risk to public health. The effects of chronic low-level CO exposure are well-documented, with pregnant women, the unborn and children being particularly vulnerable. Although a number of studies have investigated the phenomenon, its current prevalence in the UK has not been examined. To address this, this study sampled CO levels from 33 vehicles driven by 28 participants. Drivers were members of the public using their cars for purposes including commutes and personal use. The study excluded vehicles carrying smokers. In all, 20 vehicles logged (60.6 per cent) logged non-zero CO at least once. Mean average ppm CO exceeded the WHO target limit of 4mg/m3 (3.49 ppm) in 4 vehicles; peak ppm CO exceeded this limit in 13 vehicles. Peak single-journey mean CO was 192.17 ppm and overall mean all-journey CO was 6.63 ppm, median 0.02 ppm. Patterns of detected CO, in some cars, were suggestive of internal fume leakage. There was a significant positive correlation between vehicle age and in-cabin CO levels. While the sample size was small, these results give grounds to consider that vehicle drivers and passengers in the UK may be exposed to CO within the passenger cabin due to leakage from the exhaust system. Wider investigation of the issue, in order to determine an appropriate public health policy response, is warranted., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr Sophie Duggan reports financial support, article publishing charges, equipment, drugs, or supplies, and statistical analysis were provided by The Carbon Monoxide Research Trust., (Copyright © 2024. Published by Elsevier Ltd.)

Energy consumption and management have emerged as crucial production functions because of the high cost of energy. Since the total consumption of fossil fuels like diesel has increased proportionally to the expansion in demand for power generation, industry, and transportation services, researchers have long been interested in constructing a more energy-efficient engine. With its improved efficiency, reduced fuel consumption, and fewer emissions, the application of nano-coating technology to engine components has become more popular in recent years. This study involved the application of a thermal barrier coating (TBC) using zirconia on the test engine piston. The aim of this research is to examine the impact of aluminium oxide nano-additives in rapeseed biodiesel blends on the performance of a diesel engine with a thermal barrier-coated piston. The four test fuels were prepared using 20% and 40% blends of rapeseed biodiesel with and without the addition of aluminium oxide at 25 ppm and 50 ppm. The full factorial design methodology was employed to examine the influential factors, specifically the rapeseed blend ratio and aluminium oxide concentration, in order to enhance performance and reduce emissions. The blends of RSB20AO25 and RSB20AO50 showed significant results on energy consumption and emissions. The RSB20AO50 blend performed with a 5.4% increase in brake thermal efficiency and a 6.5% reduction in fuel consumption compared with standard diesel. Similarly, blends of RSB20AO25 and RSB20AO50 show 6% and 11% reductions in carbon monoxide and 5.2% and 9.5% reductions in hydrocarbon emissions., Competing Interests: Declarations. Ethical approval: Not applicable. Consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Tire and road wear particles (TRWP) are a major contributor to non-exhaust traffic emissions, but their contribution to and dynamics in urban aerosol is not well known. Urban particulate matter (PM) in the size fraction below 10 µm (PM 10 ) from two German cities was collected over 2 weeks and analysed for 39 tire-related chemicals, including amines, guanidines, ureas, benzothiazoles, p-phenylenediamines, quinolines and several transformation products (TPs). Of these, 37 compounds were determined in PM 10 at median concentrations of 212 pg/m 3 for 1,3-diphenylguanidine (DPG) and 132 pg/m 3 for benzothiazole-2-sulfonic acid (BTSA); 10 of the compounds have not been reported in urban aerosol before. Median concentrations of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6-PPD), 6-PPD quinone (6-PPDQ), and 1,2-dihydro-2,2,4-trimethylquinoline (TMQ) were 1.0, 4.1, and 8.1 pg/m 3 , respectively. Some parent compounds showed positive correlation with their TPs, e.g. 6-PPD with 4-aminodiphenylamine (4-ADPA), N,N'-diphenyl-p-phenylenediamine (DPPD) with DPPD quinone (DPPDQ), and DPG with phenylguanidine (PG). The concentration pattern of the compounds in PM 10 did not agree to the pattern found for cryo-milled tire tread (CMTT mix ), likely reflecting transformation processes in tires or the aerosol and the influence from other sources than TRWP. Concentrations in PM 2.5 were determined from one of the sites and were by a factor of 4 - 10 lower than in PM 10-2.5 for 9 compounds, but a few others, mostly benzothiazoles showed similar or higher concentrations. Many of the tire-related chemicals were also determined in PM 10 of one rural site, although at median concentrations up to two orders of magnitude lower. A large number of tire chemicals with a wide concentration range is present in urban PM 10 and PM 2.5 aerosol and requires scrutiny with respect to its relevance for human exposure., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Thorsten Reemtsma reports financial support was provided by Leibniz Association. Thorsten Reemtsma reports a relationship with Leibniz Association that includes: funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

This study presents a modern mobile laboratory to monitor outdoor air quality in Bucharest, Romania, with a focus on pollutants associated with transportation. Particulate matter (PM 2 . 5 , PM 10 ), carbon monoxide (CO), ozone (O 3 ), sulfur dioxide (SO 2 ), nitrogen oxides (NO, NO 2 ), and BTEX compounds (benzene, toluene, ethylbenzene, and xylenes) were among the significant pollutants that were examined in the lab. Meteorological variables such wind direction and speed, temperature, humidity, and solar radiation were also routinely observed in order to assess their influence on pollution levels. The study looked at two locations-a bustling city road in Bucharest and a remote community 40 kmawayin Snagov-under a range of weather conditions, including sunny, rainy, warm, and chilly days. The findings showed that the primary source of pollution in the urban area, which had significantly higher pollution levels than the rural site, was transportation. Particularly in the city, alarming concentrations of harmful particulate matter and carcinogens like benzene were found, underscoring the need for continuous air quality monitoring. The weather has a major impact on the dispersal of contaminants. Because of washout effects, rainy days decreased airborne pollutants, but sunny days showed higher pollution deposition. This study highlights the importance of outdoor air quality monitoring, particularly in urban environments, where traffic and weather have a significant impact on pollution levels. These findings provide crucial data that policymakers can utilize to implement targeted pollution control measures that protect human health.

Brazil's significantly large fleet of ethanol-powered vehicles makes it unique with regard to mobile source emissions. An accurate estimation of emission rates is best obtained from studies reflecting real-world vehicular conditions, such as tunnel investigations. Although laboratory-based estimations are standardized, they may not reflect reality. This study evaluates two methods for estimating emission factors that arise from the circulating fleet of vehicles that travel through the Rebouças Tunnel in Rio de Janeiro. The two monitoring points were located in the L1 gallery of the tunnel. Thirteen sampling campaigns took place between 2017 and 2020. The Pierson correlation method yielded emission rates for total aldehydes of 22.1 ± 6.9 mg km -1 , while the fuel consumption testing method resulted in rates of 17.7 ± 7.8 mg km -1 . Acetaldehyde predominated in both methods, as it is a major constituent of the exhaust emissions using ethanol as fuel, which is one of the major component fuels in the Brazilian fuel matrix. Benzene emerged as the most abundant BTEX compound, with 3.7 ± 3.2 mg km -1 , when the Pierson method was used, and 2.5 ± 0.3 mg km -1 with the fuel consumption testing method. Naphthalene, which was mainly collected in the gas phase, showed rates of 1.4 ± 1.0 mg km -1 (Pierson) and 0.9 ± 0.4 mg km -1 (fuel consumption). Despite these methodological variations, our findings converge, which suggests that the choice of method should depend on available resources. The Pierson method, which requires a vehicle counting method for traffic flow, obviates the need for CO and CO 2 concentration measurements, that are essential for determining fuel consumption., Competing Interests: Declarations. Ethics approval: All authors have read, understood, and have complied as applicable with the statement on “Ethical responsibilities of Authors” as found in the Instructions for Authors. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Benzene, toluene, ethylbenzene, xylenes (BTEX) and formaldehyde (HCHO) impact the environment and human health due to their deleterious effect and are of great concern. In the present study, diurnal and seasonal trend of BTEX and HCHO along with trace gases are reported. BTEX samples were collected by activated charcoal tubes and analysed by Gas Chromatograph coupled with Mass Spectrometer and Flame Ionization Detector (GC-MS/FID) and formaldehyde sampling was done by impinger method and analysed by UV-Visible Spectroscopy. Summation BTEX varied from 50.3 to 188.3 µg m -3 (average = 74.8 ± 31.8 µg m -3 ). Amongst all species, toluene was the most abundant. Highest levels of BTEX, NO x and CO were observed in winter (96.4 ± 39.1 µg m -3 , 11.9 ± 7.8 ppb and 540.8 ± 402.0 ppb respectively) probably due to enhanced local emissions, stagnant weather conditions resulting in dilution and dispersion of pollutants and weak photochemical removal. Lower values are seen during monsoon (58.6 ± 25.4 µg m -3 , 7.6 ± 6.1 µg m -3 and 149.8 ± 68.7 µg m -3 ) as a consequence of rain showers and washout effect leading to clean atmospheric conditions. Further, ozone forming potential (OFP) BTEX was determined based on their reactivity with OH˙radical and concentration. Toluene (90.9 µg m -3 ) was the largest contributor to ozone formation, whereas benzene (9.1 µg m -3 ) was the lowest. Source apportionment of BTEX was determined based on estimation of diagnostic ratios, correlations and positive matrix factorization (PMF) analysis and revealed emissions from vehicles was the main source. Air mass back trajectory analysis for different seasons shows the impact of long-range during the summer season and localized air masses during winter season. The results of the current study provide a better understanding of OFP and sources of BTEX and HCHO to formulate effective pollution management., Competing Interests: Declarations. Ethical approval: This study was conducted as per the guidelines of the institute ethical committee. Consent to participate: Consent of all the authors to participate in the study was obtained. Consent to publish: Consent of all the authors was obtained for the publication of manuscript. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

One of the sources of chronic exposure to potentially toxic elements (PTE), especially in polluted environments, is the inhalation of resuspended road dust (RD). The aim of this study is to assess the inhalation bioaccessibility of PTE in RD from highly polluted environments from mining/smelting industries and traffic, and to identify any correlations between the bioaccessibility fraction of PTE and the physicochemical characteristics of the particles. RD from the studied area contains extremely high total concentrations of Cr, V, and Mn, which are likely due to pollution from the smelting industry. Additionally, elevated total concentrations of other elements associated with traffic emissions including Zn, Cu, Pb, Sb, and Sn were also measured. The bioaccessibility of PTE was assessed using two synthetic extraction solutions - Gamble's solution (GS) and Artificial Lysosomal Fluid (ALF). The majority of elements showed negligible bioaccessibility in GS. However, quite high inhalation bioaccessibility was observed for Zn, Pb, Sb, Cd, and Mn in the ALF solution, with a mean bioaccessible fraction of 49, 51.5, 41, 50, and 40% respectively. The highest bioavailable fraction was measured for Cd (97%) in a sample collected near a steel production facility and for Pb (95%) in a sample collected near the highway. These results indicate that increased mobility of the elements in inhaled particles occurs only in the case of phagocytosis. The lowest inhalation bioavailability was measured for Cr (mean is 3%). Differential individual particle analysis revealed that about 60% of phases, mostly major (Cr,Ti,V)-bearing metallic alloys, silicates, oxides and sulphides, are stable in ALF solution, while 40% of phases, mostly (Fe,Ca,Mn)-bearing oxides, silicates, sulphides, metals and metallic alloys originating from steel production, ferrochrome, ferrosilicon and vanadium production and from traffic emissions have been heavily corroded or completely dissolved. The study provides valuable information to further assess health hazards from various emission sources., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Exposure to traffic-related air pollution and ultrafine particles (<100 nm; UFP) is linked with neurodegeneration. However, the impact of the aromatic content in fuels and the contribution of different fractions of UFP, i.e., solid UFP vs SVOC UFP, on neuronal function is unknown. We therefore studied effects on neuronal activity and viability in rat primary cortical cells exposed for up to 120 h to copper oxide particles (CuO) or UFP (solid and SVOC) emitted from a heavy-duty diesel engine fueled with petroleum diesel (A20; 20 % aromatics) or Hydrotreated Vegetable Oil-type fuel (A0; 0.1 % aromatics), or solid UFP emitted from a non-road Kubota engine fueled with A20. Moreover, effects of UFP and CuO upon simulated inhalation exposure were studied by exposing an lung model (Calu-3 and THP-1 cells) for 48 h and subsequently exposing the cortical cells to the medium collected from the basal compartment of the lung model. Additionally, cell viability, cytotoxicity, barrier function, inflammation, and oxidative and cell stress were studied in the lung model after 48 h exposure to UFP and CuO. Compared to control, direct exposure to CuO and SVOC UFP decreased neuronal activity, which was partly associated with cytotoxicity. Effects on neuronal activity upon direct exposure to solid UFP were limited. A20-derived UFP (solid and SVOC) were more potent in altering neuronal function and viability than A0 counterparts. Effects on neuronal activity from simulated inhalation exposure were minor compared to direct exposures. In the lung model, CuO and A20-derived UFP increased cytokine release compared to control, whereas CuO and SVOC A20 altered gene expression indicative for oxidative stress. Our data indicate that SVOC UFP exhibit higher (neuro)toxic potency for altering neuronal activity in rat primary cortical cells than the solid fraction. Moreover, our data suggest that reducing the aromatic content in fuel decreases the (neuro)toxic potency of emitted UFP., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Air pollution from transport hubs is a recognised health concern for local urban inhabitants. Within the domain of transport hubs, significant attention has been given to larger airport and port settings, however concerns have been raised about emissions from urban railway hubs, especially those with diesel trains. This paper presents an approach that adopts low-cost monitoring (LCM) for fixed site monitoring (FSM) to quantify and disaggregate PM 2.5 and NO 2 contributions from railway station and road traffic on air quality in the vicinity of railway station in Dublin, Ireland. The NO 2 sensor showed larger discrepancies than the PM 2.5 sensor when compared to the reference monitor. Machine learning models (XGBoost and Random Forest (RF) regression) were applied to calibrate the LCM devices, with the XGBoost model (NO 2, R 2  = 0.8 and RSME = 9.1 μg/m 3 & PM 2.5 , R 2  = 0.92 and RSME = 2.2 μg/m 3 ) deemed more appropriate than the RF model. Local wind conditions, pressure, PM 2.5 concentrations, and road traffic significantly impacted NO 2 model results, while raw PM 2.5 sensor readings greatly influenced the PM 2.5 model output. This highlights that the NO 2 sensor requires more input data for accurate calibration, unlike the PM 2.5 sensor. The monitoring results from the one-month monitoring campaign from May 25, 2023 to June 25, 2023 presented elevated NO 2 and PM 2.5 concentrations measured at the railway station, which translated to exceedances of the annual WHO limits (PM 2.5  = 5 μg/m 3 , NO 2  = 10 μg/m 3 ) by 1.6-1.8 and 3.2-5.2 times respectively at the study site. A subsequent data filtering technique based on wind orientation, revealed that the railway station was the main PM 2.5 source and road traffic was the main NO 2 source when winds come from the railway station. This study highlights the value of LCM devices alongside robust machine learning techniques to capture air quality in urban settings., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Shanmuga Priyan reports financial support was provided by Environmental Protection Agency. Yuxuan Guo reports financial support was provided by Environmental Protection Agency. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Assessing the emissions of heavy-duty diesel trucks (HDDTs) is crucial for managing air quality in megacities, especially concerning nitrogen oxides (NO X ) and black carbon (BC). This study employed mobile plume chasing to monitor the real-world emissions of over 7778 HDDTs in Shenzhen. The findings indicate that the real-world NO X emission factors (EF) of China IV trucks did not differ significantly from those of China III, whereas China V and VI vehicles demonstrated fleet-averaged reductions of 27% and 85%, respectively. For China V, a significant decrease in the NO X EF for HDDTs registered after 2017 was attributed to the installation of advanced aftertreatment systems, including diesel oxidation catalysts (DOC) and Diesel Particle Filters (DPF), along with selective catalytic reduction (SCR). These technologies led to an average reduction of 42% in NO X and 61% in BC emissions. Seasonal variations were pronounced, with winter (∼20 °C) NO X EF 40% higher than summer (∼35 °C) levels. Conversely, BC EF decreased by 26% in winter, indicating significant impacts of ambient temperature on emissions. Spatial analysis revealed that the average NO X EF of HDDTs on east freeways was 1.4 times higher than that on urban expressways, influenced by variations in the proportion of vehicle types segmented by usage. These findings offer a comprehensive perspective on HDDTs emissions, highlighting the importance of large-scale emission monitoring through plume chasing for precise and effective control of real-world HDDTs emissions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Ambient polycyclic aromatic hydrocarbons (PAHs) originate predominantly from fuel combustion of motor vehicles and have the potential to affect human health. However, there is insufficient knowledge regarding serum PAHs health risks among the Malaysian population. This study aims to compare PAH concentrations, distributions, correlations, and health risks in 202 blood serum samples drawn from residents living in high-traffic volume areas (Kuala Lumpur) and low-traffic volume areas (Hulu Langat) in Malaysia. Solid phase extraction and gas chromatography-mass spectrometry (GC-MS) were employed to extract and analyze blood serum samples. Questionnaires were distributed to obtain sociodemographic and contributing factors of serum PAHs. The mean total PAHs concentration in serum of the Kuala Lumpur group was 54.44 ng g -1 lipids, double the Hulu Langat group's concentration (25.7 ng g -1 lipids). Indeno(1,2,3-cd)pyrene (IcP) and acenaphthene (ACP) feature the most and least abundant compounds in both study groups. The mean concentrations of IcP and ACP in the Kuala Lumpur and Hulu Langat groups were 26.8 vs 12.68 and 0.27 vs 0.14 ng g -1 lipids, respectively. High-molecular-weight PAHs (HMW-PAHs) composed 85% of serum total PAHs in both groups. Significant correlations were found (i) between the individual serum PAH congeners (p < 0.01) and (ii) between serum PAHs and total lipids (p < 0.01). According to the questionnaire data, high traffic volume and outdoor hobbies were the only contributory factors that confirmed significant relationships with serum PAHs (p < 0.001). Health risk assessment was computed using benzo(a)pyrene (BaP) equivalent (BaPeq) and demonstrated that the Kuala Lumpur group has twofold greater carcinogenic risk than the Hulu Langat group (16.11 vs 7.76 ng g -1 lipids). Our study reveals that traffic volumes notably impact serum PAH levels and general health among the Malaysian population., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Yu Bin Ho reports financial support was provided by Ministry of Higher Education Malaysia. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Traffic emissions are an important source of air pollution worldwide, but in the Middle East, this problem is exacerbated by weak or no enforcement of emission regulations. Comprehensive measurements of fine PM emission factors (EFs) from road transport in the region have not yet been conducted, but such data are necessary for quantitative assessments of the health impact of transport emissions in the region. To address this need, PM 2.5 samples collected inside the Salim Slam tunnel in Beirut, Lebanon were analyzed for carbonaceous matter (organic carbon (OC) and elemental carbon (EC)), water-soluble ions, elements, and selected organic compounds. The OC/EC ratio was 1.8 for the total fleet and 2.6 for light-duty vehicles (LDV), in agreement with the dominant proportion of gasoline LDV in the Lebanese fleet. A Cu/Sb ratio of 4.2 ± 0.1 was observed, offering a valuable metric for detecting brake wear emissions in subsequent studies conducted in the region. The EFs of carbonaceous matter, elements and ions generally varied by a factor 0.1 and 10 in comparison to literature values, while those for alkanes and polycyclic aromatic hydrocarbons were similar to the upper values previously reported. The average number size distribution was characterized by a single mode around 35 nm. The particles number EF (for diameters between 10 and 480 nm) was within the range of 10 14 -10 15 particles per kg of fuel. The chemical mass balance model showed an average contribution to EF of 62% from non-exhaust sources. This study highlights the need for more enforceable stringent vehicular regulations because of the local practices (i.e., removal of catalyst) and some EF values are very high compared to other studies/countries., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

With stringent regulations of internal combustion engine on reducing CO 2 emission, ammonia has been used as an alternative fuel. Investigating how engine-related performance is affected by partial ammonia replacement of diesel fuel is essential for understanding the combustion. Therefore, in this study, a three-dimensional numerical simulation model is developed for the burning of two fuels of diesel and ammonia based on relevant parameters (i.e., compression ratio, load, ammonia energy fraction, etc.) in a lab-made diesel engine. The consequences of load and compression proportion on combustion and pollutant emissions are investigated for ammonia energy fractions between 50% and 90%. When the ammonia portion rises, the increased ammonia equivalent ratio causes ammonia to move away from the dilute combustion boundary and accelerates the combustion rate of ammonia. An increase in compression ratio significantly increases the specified thermal performance and combustion efficacy. When the compression ratio is 16, as the ammonia energy fractions increases, due to the increase in the proportion of ammonia, that is, the proportion of nitrogen atoms increases, more NOx is generated during the combustion process. When the ammonia substitution rate is 90%, as the compression ratio increases, the cylinder pressure and temperature increase. The combustion efficiency of ammonia increases, generating more NOx and NOx emissions can reach 0.66 mg/m 3 . At a compression ratio of 18, the NOx emissions can reach 1.59 mg/m 3 . However, under medium and low load conditions, as the ammonia fraction increases, the total energy of fuel decreases, and the combustion efficiency of ammonia decreases, resulting in a decrease in the heat released during combustion and a decrease in NOx emissions. When the ammonia substitution rate is 90% and the load is 25%, NOx emissions reach 0.1 mg/m 3 . This research provides theoretical suggestions for the profitable and use ammonia fuel in internal combustion engines in a clean manner., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)