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Vehicular emissions are a major culprit in the rise of urban air pollution. The particulate matter (PM) emitted from vehicular sources includes primarily ultrafine particles (UFPs) with aerodynamic diameters less than 0.1 µm (PM0.1) and is linked to adverse respiratory and cardiovascular health effects. Despite this knowledge, few exposure assessment studies exist that detail the physicochemical properties of PM in parking garages. In this study, airborne PM emitted by vehicles in a parking garage of a hospital in New Jersey was sampled, during winter and summer seasons, and physicochemically characterized. The results indicate that the mass concentrations of the UFPs in the garage were 2.51 µg/m3 and 3.59 µg/m3, respectively. These UFPs contained a large percentage of elemental carbon and toxic elements. They also contained polycyclic aromatic hydrocarbons (PAHs), having deleterious health effects. An inhalation particle modeling revealed that 23.61% of these UFPs are deposited in the pulmonary region of the lung, translating to a dose of 10.67 µg for winter and 15.25 µg for summer, over a typical 40 h work week. These high deposited levels of UFPs and their complex chemistry levels further warrant the need for toxicological assessment of UFPs related to vehicular emissions. [ABSTRACT FROM AUTHOR]

The research aims to assess the risks associated with the transport-induced emissions (major criteria pollutants) in Adelaide, South Australia. A stochastic emission modelling strategy was implemented for a probabilistic risk assessment of the transport system for current and future scenarios, by analysing the road specific transport system data. The simulated result suggests that NOx and PM2.5 risks are significant at about 35% of city areas, especially along the roads with heavy vehicle concentration and higher traffic. The risk will significantly increase in 10 years if the current practice persists, demonstrating a high probability (more than 60%) of emissions above 150% of the air quality standard. The research suggests that appropriate planning is necessary to cope with the development needs for the system's future sustainability. [ABSTRACT FROM AUTHOR]

Transformation in the transportation sector is imperative to address the environmental issues and combat climate change. The study examined the determinants of intention to adopt cycling as a sustainable work travel mode among individuals in mumbai city. The responses were collected using a structured questionnaire based on the theory of planned behaviour. Individuals riding a cycle or sometimes using a cycle to workplace were the target audience of the study. Sem technique was used to identify the significant determinants of intention to adopt cycling as a sustainable work travel mode. The analysis found the "perception of environment" as the only significant contributor to the intention to adopt cycling as a sustainable work travel mode. The study highlights the urgent need to augment the infrastructure for cycling. The findings of the study may help enhance the usage of cycles as a work travel mode. [ABSTRACT FROM AUTHOR]

Transformation in the transportation sector is imperative to address the environmental issues and combat climate change. The study examined the determinants of intention to adopt cycling as a sustainable work travel mode among individuals in mumbai city. The responses were collected using a structured questionnaire based on the theory of planned behaviour. Individuals riding a cycle or sometimes using a cycle to workplace were the target audience of the study. Sem technique was used to identify the significant determinants of intention to adopt cycling as a sustainable work travel mode. The analysis found the "perception of environment" as the only significant contributor to the intention to adopt cycling as a sustainable work travel mode. The study highlights the urgent need to augment the infrastructure for cycling. The findings of the study may help enhance the usage of cycles as a work travel mode. [ABSTRACT FROM AUTHOR]

Transformation in the transportation sector is imperative to address the environmental issues and combat climate change. The study examined the determinants of intention to adopt cycling as a sustainable work travel mode among individuals in mumbai city. The responses were collected using a structured questionnaire based on the theory of planned behaviour. Individuals riding a cycle or sometimes using a cycle to workplace were the target audience of the study. Sem technique was used to identify the significant determinants of intention to adopt cycling as a sustainable work travel mode. The analysis found the "perception of environment" as the only significant contributor to the intention to adopt cycling as a sustainable work travel mode. The study highlights the urgent need to augment the infrastructure for cycling. The findings of the study may help enhance the usage of cycles as a work travel mode. [ABSTRACT FROM AUTHOR]

In the last few years, urban trees have emerged as an effective nature‐based solution to mitigate increasing air pollutant levels due to urbanization and industrialization. This study aims to assess the synergistic effect of urban trees on improving air quality by combining real‐time PM2.5 monitoring with the i‐Tree Eco model. The monitoring was conducted during rush hours with high traffic volume and during non‐rush hours, in both the tree alley and a non‐tree road section within the industrial areas of the north‐west region of the National Capital Territory of Delhi, India. The i‐Tree Eco model was run using the diameter at breast height values of tree species present in the study area, and the PM2.5 reduction ability of the trees was quantified. The results from both approaches indicated that urban trees can significantly reduce the traffic‐fed PM2.5 concentrations. Therefore, it is suggested that tree plantations be integrated into air pollution management strategies in urbanized regions with high traffic volumes. Although this study explores the initial link between trees and air quality in Delhi, further research incorporating local wind speed and direction measurements would provide a more comprehensive understanding of how trees influence air quality in any highly polluted urban setting. [ABSTRACT FROM AUTHOR]

Carbon monoxide (CO) is a prominent air pollutant in cities, with far-reaching implications for both local air quality and global atmospheric chemistry. The long-term change in atmospheric CO levels at a specific location is influenced by a complex interplay of local emissions, atmospheric transport, and photochemical processes, making it a subject of considerable interest. This study presents an 8-year analysis (2014–2021) of in situ CO observations using a cutting-edge laser-based analyzer at an urban site in Ahmedabad, western India. The long-term observations reveal a subtle trend in CO levels, masked by contrasting year-to-year variations, particular after 2018, across distinct diurnal time windows. Mid-afternoon (12:00–16:00 h) CO levels, reflecting background and regional conditions, remained relatively stable over the study period. In contrast, evening (18:00–21:00 h) CO levels, influenced by local emissions, exhibited substantial inter-annual variability without discernible trends from 2014 to 2018. However, post-2018, evening CO levels showed a consistent decline, predating COVID-19 lockdown measures. This decline coincided with the nationwide adoption of Bharat stage IV emission standards and other measures aimed at reducing vehicular emissions. The COVID-19 lockdown in 2020 further resulted in a noteworthy 29% reduction in evening CO levels compared to the pre-lockdown (2014–2019) period, highlighting the potential for substantial CO reduction through stringent vehicular emission controls. The observed long-term changes in CO levels do not align with the decreasing emission estimated by various inventories from 2014 to 2018, suggesting a need for improved emission statistics in Indian urban regions. This study underscores the importance of ongoing continuous CO measurements in urban areas to inform policy efforts aimed at controlling atmospheric pollutants. [ABSTRACT FROM AUTHOR]

Background: Air pollution from vehicular emission and other sources accounts for over seven million global deaths annually and contributes significantly to environmental degradation, including climate change. Vehicular emission is not prioritized for control in Nigeria, thus undermining public health and the Sustainable Development Goals 3, 11 and 13. This study aims to characterize vehicular emissions in Abuja municipality and quantify exhaust air pollutants of commonly used vehicles. Methodology: Cross-sectional exhaust emissions study of vehicles in Abuja Municipal Area Council. Information on the type and age, fuel type, purchase and use category of 543 vehicles on routine Annual Road Worthiness Test at the Computerized Test Center, Abuja. Exhaust levels of CO, CO2 HCHO and PM10 were measured using handheld devices. IBM SPSS version 26.0.0.0 (2019) statistical software. Results: Toyota brand comprised 52.5% of the vehicles. Over 80% were older than 10 years; 85.5% preowned and 87.3% used for private purposes. PMS was the dominant fuel used (91.1%). Except PM10, older vehicles emitted higher levels of the measured pollutants than newer ones. The differences were significant for CO and HCHO. Diesel-fueled and commercial vehicles also emitted higher levels of CO, HCHO and PM10 compared to PMSfueled and private vehicles respectively. Conclusions: Strong regulatory policies that discourage over-aged vehicles; speedy adoption of the ECOWAS guidelines on cleaner fuels and emission limits; and coordinated implementation of effective Inspection & Monitoring programme by relevant government agencies are required to safeguard public health and the environment. We also recommend the introduction of vehicles powered by alternative energy, use of bicycles, designation of one-way traffic and pedestrian zones. [ABSTRACT FROM AUTHOR]

Internal combustion engines have played a crucial role in the advancement of society. Consequently, there has been a persistent need to enhance their efficiency and performance. The water-injected six-stroke engine is based on conventional four-stroke engines, producing additional power by injecting water into the hot combustion products during the expansion stroke, thereby increasing the overall engine efficiency. However, a comprehensive review that consolidates existing knowledge and identifies future research opportunities in six-stroke engine technology is lacking. This study addresses this gap by thoroughly examining the thermodynamic operation of six-stroke engines and analyzing the impact of water injection on engine performance. The review covers literature from 1994 to 2023, categorizing studies based on the modeling approach, working fluid, thermodynamic cycle, and consideration of heat transfer. Among the 18 analyzed articles, predominantly published from 2015 to 2019, half utilize analytical models, while the rest employ experimental models addressing heat transfer losses. Notably, water injection exhibits a substantial influence, manifesting as a 5.18% increase in brake power and a 1.55% enhancement in thermal efficiency, particularly with acetylene as the working fluid. Finally, a literature overview of water injection in hot gas environments within the engine cylinder was conducted in addition to a preliminary thermodynamic analysis of the Otto and Diesel cycles to compare different configurations outlined in the literature. The lack of studies, experimental setups, and non-idealized models that consider factors such as heat transfer or water evaporation during injection is evident. By critically synthesizing the available literature, this study offers valuable insights into the potential advantages, limitations, and prospects of six-stroke engine studies. [ABSTRACT FROM AUTHOR]

Vehicular emissions are a major culprit in the rise of urban air pollution. The particulate matter (PM) emitted from vehicular sources includes primarily ultrafine particles (UFPs) with aerodynamic diameters less than 0.1 µm (PM0.1) and is linked to adverse respiratory and cardiovascular health effects. Despite this knowledge, few exposure assessment studies exist that detail the physicochemical properties of PM in parking garages. In this study, airborne PM emitted by vehicles in a parking garage of a hospital in New Jersey was sampled, during winter and summer seasons, and physicochemically characterized. The results indicate that the mass concentrations of the UFPs in the garage were 2.51 µg/m3 and 3.59 µg/m3, respectively. These UFPs contained a large percentage of elemental carbon and toxic elements. They also contained polycyclic aromatic hydrocarbons (PAHs), having deleterious health effects. An inhalation particle modeling revealed that 23.61% of these UFPs are deposited in the pulmonary region of the lung, translating to a dose of 10.67 µg for winter and 15.25 µg for summer, over a typical 40 h work week. These high deposited levels of UFPs and their complex chemistry levels further warrant the need for toxicological assessment of UFPs related to vehicular emissions.

Lucknow is one of the most polluted metro-city in India with increasing vehicular density and fuel consumption in the last three decades. The study was conducted during years 2019–2021 for measurement of fine particulate matter (PM2.5), nitrogen dioxide (NO2), sulphur dioxide (SO2), respirable particulate matter (PM10), and noise levels at nine selected sites; 4 residential, 4 commercial, and 1 industrial, encompassing prior-to-lockdown, during-lockdown, and after-lockdown periods. Values of PM10 for prior-to-lockdown, during-lockdown, and after-lockdown period ranged from 133.2 to 197.4, 77.0 to 135.0, and 91.4 to 148.0 µg/m3, respectively while values of PM2.5 were 66.5 to 93.6, 41.9 to 67.5 and 49.5 to 98.6 µg/m3, respectively. Corresponding values of SO2 ranged from 8.7 to 12.8, 5.5 to 7.6, and 11.4 to 17.6 µg/m3, respectively while values of NO2 were 24.6 to 57.0, 20.5 to 32.8, and 26.1 to 43.8 µg/m3, respectively. Order of the trace metals associated with PM2.5 is Co < Cd < As < Cr < Ni < Cu < Pb < Mn < K < Zn, Co < Cd < As < Cr < Cu < Ni < Pb < Mn < Zn < K and Cd < Co < As < Cr < Cu < Ni < Pb < Mn < K < Zn in the same periods. Statistical data evidenced that the air quality of the city witnessed drastic improvement during the COVID-19 pandemic. WHO AIRQ + was utilized to calculate attributable health risk and post-neonatal disease burden; showing 1447 ± 768 estimated number of cases attributable to ambient PM10 per lakh of population. Regulatory authorities need to establish new benchmarks for the prevention and management of public health risks for urban resilience and environmental management for episodic events in the near future. [ABSTRACT FROM AUTHOR]

This article provides an overview of the main findings of a survey on the effects of ambient temperature and humidity on vehicular emissions of criteria pollutants and greenhouse gases. The present study is focused on the emissions of Carbon Monoxide (CO), Nitrogen Oxides (NOX), Sulfur Oxides (SOX), Particulate Matters (PM), Carbon Dioxide (CO2 ), Nitrous Oxide (N2O), and Methane (CH4 ) from gasoline engine passenger cars. In this analytical research, the International Vehicle Emissions (IVE) model was operated, using long-term meteorological data to determine the effects of various ambient temperature and humidity levels on exhaust pipe pollutants and greenhouse gas emissions. The results of present study indicated that as the ambient temperature increases from -7.5 °C to 20 °C, CO, NOX, and CH4 emissions decrease by 35.8%, 6.46%, and 21.44%, respectively, while SOX, PM, CO2, and N2O emissions remain constant. In contrast, increasing the ambient temperature from 20 °C to 37.5 °C increases the emissions of all the investigated pollutants and greenhouse gases. On the other hand, the findings showed that as the ambient humidity increases from 8% to 98% CO and CH4 emissions increase by 7.3% and 2.13%, respectively; while NOX emissions decrease by 16.84%. However, humidity changes did not have noticeable impact on the emissions of SOX, PM, CO2, and N2O. This study concluded that changes in meteorological parameters over a certain period of time, not only affect global warming, but also the emissions of criteria pollutants. [ABSTRACT FROM AUTHOR]

One of the policies adopted to reduce vehicular emissions is subway network expansion. This work fitted interrupted regression models to investigate the effects of the inauguration of subway stations on the mean, trend, and seasonality of the NO, NO2, NOx, and PM10 local concentrations. The regions investigated in the city of São Paulo (Brazil) were Pinheiros, Butantã, and St. Amaro. In Pinheiros, after the inauguration of the subway station, there were downward trends for all pollutants. However, these trends were not significantly different from the trends observed before. In Butantã, only regarding NO, there was a significant reduction and seasonal change after the subway station's inauguration. In St. Amaro, no trend in the PM10 concentration was noted. The absence of other transportation and land use policies in an integrative way to the subway network expansion may be responsible for the low air quality improvement. This study highlights that the expansion of the subway network must be integrated with other policies to improve local air quality. [ABSTRACT FROM AUTHOR]

The transport sector is the second leading emitter of greenhouse gas emissions (GHGEs) from fuel combustion activities on a global scale. Reducing emissions related to this sector requires detailed data about the emissions by vehicle type and traveled distance. Generally, these data are missing in developing countries, which makes difficult the establishment of effective policies for the reduction of these emissions. This paper presents a hybrid method to estimate these emissions using the IPCC 2006 guidelines. The method combines bottom-up and top-down approaches to estimate vehicular emissions using data about the vehicle type, vehicle kilometers traveled, and fuel consumption. This method is applied for the first time for the Palestinian territory. Data have been collected from the administration, official reports, and papers. The results show a significant increase in the total vehicles in Palestine, particularly diesel vehicles. Emissions from the on-road transport system were approximately 2,207,834 tons of CO2eq in 2019. Diesel vehicles were responsible for about 75% of these emissions. Private cars were the most significant contributor to these emissions, with a share exceeding 50% of the total emissions, followed by commercial vehicles and light trucks (20%), public taxis (9%), and buses (7%). These results show clearly that the GHGEs reduction policies in Palestine should focus on diesel and private vehicles by developing the public transport systems and replacing diesel and gasoline vehicles with more environmentally friendly vehicles, such as hybrid and electric cars. [ABSTRACT FROM AUTHOR]

Airborne particulate matter is a serious threat to human health, especially in fast-growing cities. In this study, we carried out a magnetic and elemental study on tree leaves used as passive captors and urban dust from various sites in the city of Santiago, Chile, to assess the reliability of magnetic and elemental measurements to characterize particulate matter pollution from vehicular origin. We found that the magnetic susceptibility and saturation isothermal remanent magnetization measured on urban tree leaves is a good proxy for tracing anthropogenic metallic particles and allow controlling the exposure time for particulate matter collection, in agreement with other studies carried out in large cities. Similar measurements on urban soil can be influenced by particles of detritic (natural) origin, and therefore, magnetic measurements on tree leaves can help to identify hotspots where fine particles are more abundant. Elemental particle-induced X-ray emission analysis of tree leaves showed the presence of a number of elements associated with vehicular emissions, in particular Cu, Zn, Fe, K and S which are present at every site, and As, Se, V, Ni, Sr, Zr, Mo and Pb identified at some sites. We observed a correlation between magnetic parameters and the concentrations of S and Br as well as Cu to a smaller extent. Moreover, this study shows the importance of selecting carefully the tree species as well as the location of trees in order to optimize phytoremediation. [ABSTRACT FROM AUTHOR]

Starting around 2008, there was rapid expansion of oil and natural gas (ONG) production into more heavily populated areas within the Dallas-Fort Worth metroplex in the Barnett Shale region of Texas. This colocation raised concerns regarding the effect of ONG activities on chemical levels in the air. In the current study, we examined the potential impacts of ONG activity on the types and concentrations of chemicals in ambient air in the Barnett Shale. Volatile organic compound (VOC) concentrations from 6–12 years (2008–2019) of hourly ambient air monitoring data from 15 monitors (4 monitors had ≥ 10 years of data) were compared to several metrics of ONG activity (number of active wells, natural gas production, condensate production) within a 2-mile radius of each monitor. Monitoring sites were also classified into urban, suburban, and rural areas as a surrogate for nearby vehicular emission sources. Analyses of this huge dataset showed that both peak and mean chemical concentrations of lighter alkane hydrocarbons (e.g., ethane) were most impacted by the number of gas wells. Levels of heavier alkanes (e.g., pentane) were increased by condensate production and at monitors located in areas with greater urbanicity, and therefore higher vehicular emissions. The levels of unsaturated alkynes (e.g., ethylene) were entirely driven by urbanicity and were unaffected by nearby ONG activity. The same pattern was seen with the ratio of iso:n-pentane, which is contrary to the findings of others and suggests an area for future research. Aromatic hydrocarbons were impacted by multiple emissions sources and did not show the same patterns as non-aromatic VOCs. No VOC concentrations were at levels of concern for human health or odor based on comparison to Texas air monitoring comparison values. Overall, ONG activities impact air quality, but this must be evaluated in the context of other emission sources such as automobiles.

Key message: An integrated approach of physiological- and biophysical-based indicators was used to assess the tolerance of roadside plantations of Alstonia scholaris towards urban roadside air pollution caused due to heavy traffic movements. It was inferred that A. scholaris is a tolerant species to vehicular emissions and can be used to develop roadside plantations and other green spaces in an urban setup. Vehicles are a significant source of pollution affecting the urban environment. Roadside plantations are one of the first defense lines to minimize the impacts of air pollution; at the same time, they also suffer from the adverse effects of pollution. In the present study, an integrated approach, i.e., a combination of physiological, morphological, and biochemical indicators, was used to evaluate the tolerance of roadside plantations of A. scholaris exposed to road traffic emissions. Multiple indicator traits of adaptation and mitigation, especially biophysical (leaf thickness—LTh, dust load flux—DLF, and local cooling created by canopy—CI), physiological (CO2 assimilation rate—A, transpiration—E, stomatal conductance-gs, water use efficiency—WUE, and relative water content—RWC), and biochemical (proline—PROL, soluble sugars—SoS, ascorbic acid—AsA, leaf pH, and total chlorophyll—TChl, accumulation of heavy metals—Fe, Pb, Cd, Cr, and Cu) were used for evaluating the response to air pollutants. Besides, tolerance indices, i.e., air pollution tolerance index (APTI) and anticipated performance index (API), were developed to assess the species suitability for mitigating urban air pollution. It was observed that vehicular emissions modulate the measured functional traits in this species. Plants exposed to the polluted environment have increased LTh, DLF, CI, WUE, PROL, AsA, pH, SoS, heavy metals, while a decrease in the level of A, E, Gs, TChl, and RWC was reported. Further, it was inferred that A. scholaris is a tolerant species and can be suggested for roadside plantations to mitigate vehicular air pollution. The present study is expected to assist the evaluation of other species for adaptation and mitigation of vehicular emissions. [ABSTRACT FROM AUTHOR]

We studied the effect of an environmentally conscious nudge on the choice of car that our respondents make. Our primary data driven study was conducted after adequately reviewing the literature pertaining to the field of behavioral environmental economics. Our experiment shows that the nudge worked in most cases, except those which involve the question of prestige and status. We also found that in case if the preference for a car in particular segment is high with a small difference in carbon dioxide (CO2) emissions, then the respondents tend to choose the car of their liking. It is concluded that tools like nudges are in indeed helpful in reducing the emission levels from what we currently have. [ABSTRACT FROM AUTHOR]

Automobile emissions in urban cities, such as Peru, are significant; however, there are no published studies of the effects of these emissions on PM2.5 (fine particulate matter) formation. This study aims to analyze the contributions of vehicle aerosol emissions to the surface mass concentration of PM2.5 in the Metropolitan Area of Lima and Callao (MALC), one of the most polluted cities in Latin America and the Caribbean (LAC) known to have high concentrations of PM2.5. In February 2018, we performed two numerical simulations (control and sensitivity) using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). We considered both trace gasses and aerosol emissions from on-road traffic for the baseline simulation (hereinafter referred to as "control"); gasses without particulate emissions from vehicles were considered for the sensitivity simulation (hereinafter referred to as WithoutAerosol). For control, the model's performance was evaluated using in situ on-ground PM2.5 observations. The results of the predicted PM2.5 concentration, temperature, and relative humidity at 2 m, with wind velocity at 10 m, indicated the accuracy of the model for the control scenario. The results for the WithoutAerosol scenario indicated that the contributions of vehicular trace gasses to secondary aerosols PM2.5 concentrations was 12.7%; aerosol emissions from road traffic contributed to the direct emissions of fine aerosol (31.7 ± 22.6 µg/m3). [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are considered potentially toxic, even carcinogenic, because of their affection to public health and the environment. It is necessary to know their ambient levels and the origin of these pollutants in order to mitigate them. A concerning scenario is the one in which commercial/administrative, industrial, and residential activities coexist. In this context, Gran La Plata (Argentina) presents such characteristics, in addition to the presence of one of the most important petrochemical complexes in the country and intense vehicular traffic. The source apportionment of PAH emission in the region, associated to 10-µm and 2.5-µm particulate matter fractions, was studied. First, different missing value imputation methods were evaluated for PAH databases. GSimp presented a better performance, with mean concentrations of ∑PAHs of 65.8 ± 40.2 ng m−3 in PM10 and 39.5 ± 18.0 ng m−3 in PM2.5. For both fractions, it was found that the highest contribution was associated with low molecular weight PAHs (3 rings), with higher concentrations of anthracene. Emission sources were identified by using principal component analysis (PCA) together with multiple linear regression (MLR) and diagnostic ratios of PAHs. The results showed that the main emission source is associated with vehicular traffic in both fractions. Classification by discriminant analysis showed that emissions can be identified by region and that fluoranthene, benzo(a)anthracene, and anthracene in PM10 and anthracene and phenanthrene in PM2.5 are a characteristic of emissions from the petrochemical complex. [ABSTRACT FROM AUTHOR]

Emission of carbon monoxide (CO) poses unprecedented risks in urban environments. Moreover, there has been a growing concern about the incidences of deaths arising from suffocation by CO fumes in Nigeria. Hence, this study attempts to evaluate the spatial and diurnal distribution of CO and its health and environmental implications in selected Niger Delta areas of Port Harcourt (Rivers State), Yenagoa (Bayelsa State) and Effurun-Warri (Delta State). MultiRAE PLUS and PCMM05 Pyle® Carbon Monoxide Meter were used for in situ measurement. Spatial distribution amongst all the sampling locations shows that Rumuola Junction in Port Harcourt (Rivers State) ranked the highest in CO concentration with a mean value of 120.6 ppm while DSC Roundabout in Effurun/Warri (Delta State) ranked the lowest with a mean value of 6.1 ppm. Diurnal variations in CO distribution were statistically significant (P < 0.05) only in Airport Road and PTI Junction (Effurun-Warri, Delta State), Berger Junction and Swali Market (Yenagoa, Bayelsa State) sampling locations. The observed concentrations were largely higher than the 10 ppm Federal Ministry of Environment limit for ambient air. The high emissions, accumulation and dispersion of CO were attributed to frequent traffic congestion and high vehicular traffic density, among others. It is recommended that road design and maintenance should be greatly improved across the Niger Delta to mitigate traffic emissions. In addition, the public transport system should be improved so as to encourage more patronage and reduce the number of private vehicles on roadways. [ABSTRACT FROM AUTHOR]

The introduction of three-way catalytic converter (TWC) to meet stringent vehicular NO x emission standards worldwide has led to an unintended consequence of vehicle-derived ammonia (NH 3 ) emission, which might degrade air quality and affect human health, especially in urban areas. The nitrogen stable isotope composition of NH 3 (δ 15 N-NH 3 ) may be a useful tool to trace NH 3 sources, but the isotopic signature of vehicle-emitted NH 3 is lacking. Here we report the δ 15 N-NH 3 measured from tailpipe exhausts collected directly from 19 different vehicles equipped with TWC using "grab" sample technique optimized to avoid isotopic fractionation. We found a large of range of NH 3 concentration (from 1 to 37 ppm, x̄ ± 1σ = 10 ± 8 ppm) and δ 15 N value (from -38.1 ‰ to 49.0 ‰, x̄ ± 1σ = 1.2 ± 20.9 ‰) for our samples (n = 57). Our results indicate a correlation between δ 15 N-NH 3 and NH 3 concentrations (i.e. δ 15 N-NH 3 (‰) = 16.9(± 2.2)In(NH 3 concentration; ppm) - 31.7(± 4.7) (R 2  = 0.53, P < 0.01) that is associated with the catalyst temperature, which is generally agree with the results of theoretical calculation. After consideration of the vehicle emission evolution, dominant driving condition and tunnel δ 15 N-NH 3 variation, a representative δ 15 N-NH 3 value (mean min max ) of vehicle source is identified as 0.8000 -2.2000 5.2000 , which is distinct from (larger than) other NH 3 volatilization-related emission sources. Using our newly measured δ 15 N values and Bayesian mixing model, we approximate the overall contribution of vehicles to ambient NH 3 before, during, and after an international event in Beijing was 14.1 %, 7.9 %, and 21.5 %, respectively, which agree well with the course of traffic restriction. Collectively, our findings demonstrate the importance of using vehicle-emitted δ 15 N-NH 3 to quantify vehicular NH 3 contribution in urban atmospheres., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2024. Published by Elsevier B.V.)

Nigeria deployed Intergovernmental Panel on Climate Change (IPCC) top-down approach which generalizes transport emissions, is not detailed to localize solutions based on sectors. This identified gap was filled using IPCC’s Bottom-Up approach. Quantitative research design was employed using a descriptive survey to determine fuel consumption, vehicle and drivers characteristics through the use of a 30-item instrument named GHG emission estimation instrument (GHGEEI) to estimate the quantity of GHGs from vehicular emissions of commercial road passenger transport activities within the selected routes in Iyana-ipaja, differentiate emission estimates by vehicle categories (Tricycle referred to as ‘Keke’, Shuttle,‘Danfo’14, 18 and 22-seaters) and determine the relative contribution of each commercial road passenger vehicle type according to its age, fuel type, number of engine plugs, and frequency of service. Quota sampling technique was used to identify the strata and their frequency in the population and then convenience sampling was used to select 15% of the quota population for each stratum. Results from the study showed that 10,259.88kg/CO2e, of Carbon dioxide (CO2), 3.65kg/CO2e of Methane (CH4), and 0.58kg/CO2e of Nitrous Oxide (N2O) was emitted daily on the selected areas.

We aimed to study the daily formaldehyde (HCHO) columns over urban and forested areas in São Paulo State, Brazil, from rhe TROPOMI spectrometer onboard the Sentinel-5P satellite during 2020. Nineteen specific areas were defined in four regions: 3 areas in each of two preserved Atlantic Forests (PEMD and PETAR), 3 in a sugarcane growing region (NERG) and 10 in the Metropolitan Area of São Paulo (MASP), among which 2 areas are in the Morro Grande reserve, which is a significant remnant of Atlantic Forest outside the densely urbanized area of MASP. An analysis of variance and Tukey's test showed that the mean annual columns over the Morro Grande reserve ( 1.69 ± 1.05 × 10 −4 mol/m² and 1.73 ± 1.07 × 10 −4 mol/m²) presented greater statistical similarity with the forest and rural areas of the state (< 1.70 × 10 −4 mol/m²) than with MASP (> 2.00 × 10 −4 mol/m²), indicating few effects from megacity anthropogenic emissions. Case studies addressing selected days in 2020 showed that fires in and around the state were related to episodes of maximum density of HCHO columns. The results showed significant seasonality, with lower concentrations during summer (wet season) and higher concentrations during winter and spring (dry and transition dry–wet seasons). [ABSTRACT FROM AUTHOR]

This study looked at how engine oil changes affected vehicle emissions from a variety of fuel sources and vehicle classes. Using portable emission analyzers, each car was initially examined and evaluated for baseline emissions of hydrocarbons (HC), carbon monoxide (CO), and smoke opacity (for diesel vehicles). Emissions were retested in the identical settings after a routine engine oil change. According to the findings, all vehicle kinds' emissions are considerably decreased by using new engine oil. Automobiles, motorbikes, and motorcycle rickshaws that run on gasoline demonstrated CO reductions ranging from 9% to 67% and HC reductions from 21% to 52%. With a reduction of 37.5% in smoke, the diesel bus showed a noteworthy decrease in CO, HC, and smoke emissions. The autorickshaw running on LPG showed the most gains, with CO and HC emissions falling by 60% and 49%, respectively. This study emphasizes how crucial routine engine oil changes are for reducing vehicle emissions, which can enhance air quality and protect the environment. [ABSTRACT FROM AUTHOR]

The primary aim of this research study is to assess the effect of diesel vehicles' high gases and particulate matter emissions on Quillaja saponaria Mol.'s (Quillay) photosystem II (Fv/FmPD) maximum quantum performance at pre-dawn. Q. saponaria is the most common native tree species in Santiago's (Chile) urban area. Young Q. saponaria individuals are assessed in a growth chamber under two different irrigation conditions. The results show that plants with restricted irrigation (-30 bars on average) resist coarse particulate matter better and have significantly higher Fv/FmPD values than plants without restricted irrigation (-8 bars on average). Carbon monoxide, fine particulate matter, and ozone emissions reduced Fv/FmPD significantly in irrigated plants, including plants with restricted irrigation. It is concluded that Fv/FmPD is more affected by pollutants in plants without restricted irrigation than in plants with restricted irrigation. [ABSTRACT FROM AUTHOR]

In an urban scenario, one of the air pollutants most harmful to human health and environmental is the particulate matter (PM). Considering that urban green areas can contribute to mitigating the effects of PM, this work compares the concentration of PM2.5 in two closer locations in Rio de Janeiro, in order to verify how vegetation cover can actually improve air quality. One is the entrance to the Rebouças Tunnel (RT) and the other is the Rio de Janeiro Botanical Garden (RJBG). For this purpose, PM2.5 samples were taken from September 2017 to March 2018 using a Large Volume Sampler (LVS). The results reveal that RT has a higher concentration of PM2.5 in almost all samples. The RJBG obtains concentrations around 33% less than the other area, suggesting that the presence of urban green areas like the RJBG can reduce PM2.5 levels when compared to places with less vegetation cover, providing better air quality. [ABSTRACT FROM AUTHOR]

In this research, PM10 concentrations were measured at the Universidad Nacional Tecnológica de Lima Sur (UNTELS), located in southern Lima, from March 06 to 13, 2020. To examine the aerosol-PM10 concentrations and their metals, two techniques were applied. These were: the PM10 air-mass-backward trajectory prediction and the trace metals cluster analysis in order to detect the transport of aerosol-PM10 from remote places to southern Lima, and to find the local sources of elements-particles, respectively. This was done for the first time in southern Lima. The air-mass-backward estimation trajectory of PM10 at UNTELS has shown that high values of the PM10 concentrations are associated with air masses originating and entering from the NW of Lima. However, the low values of PM10 particles are linked with the high humidity of air masses originating from the SSE coming from the Pacific Ocean. [ABSTRACT FROM AUTHOR]

This paper reviews the progress and effectiveness of Programs to Control Vehicle Emissions (PCVEs), comparing the experiences in the United States (US), European Union (EU), China, and Brazil. We present a timeline comparison of updates and differences in standards for light-duty vehicle (LDV) compliance. We then review the benefits of controlling LDV emissions on air quality, derived from previous relevant studies. Emission standards have been increasingly restricted in all evaluated PCVEs. However, some technical aspects such as dynamometer test cycles, re-testing structure of environmental protection agency, homogeneity of new and in-use vehicles inspection and maintenance, on-board diagnostics requirements are more consolidated in the US. Previous studies at different scales show the success of PCVEs in reducing vehicle emissions and air pollutant concentrations in the US, EU, China, and Brazil. Despite PCVEs has been achieving relative success, vehicular emissions are still a major threat to air quality around the world, especially in developing countries or ascending economies whose fleet grows dramatically. In places where the air quality standards recommended by the World Health Organization (WHO) are violated, it would be required the implementation of more stringent regulations with a well-designed, and homogeneous compliance policy over regional and national territories. This work contributes to clarifying the current challenges and successful experiences on regulating vehicular emissions worldwide. [ABSTRACT FROM AUTHOR]

In this study, PM2.5 and PM0.18 (particles with dp

Air pollutants, NO, NO2, and O3, were examined from April to June 2020 and compared to a 10-year (2010–2019) climatology of these pollutants for two monitoring sites in Toronto, Ontario, Canada, coinciding with local lockdown measures during the first wave of the COVID-19 pandemic. NO and NO2 values were lower than any of the preceding 10 years at the two Toronto sites for both weekdays and weekends. Ozone concentrations did not have a corresponding decrease and in fact increased for weekdays, similar to other parts of the world. The well-documented ozone weekend effect was considerably muted during the morning rush hour throughout this pandemic period. A Fisher exact test on hourly averaged data revealed statistically significant record hourly minimums for NO and NO2, but this was not found for ozone, consistent with the aggregate ranking results. These findings are likely the result of considerably reduced vehicular traffic during this time and ozone chemistry in a NOx-saturated (VOC limited) environment. This has important implications for ozone abatement strategies. [ABSTRACT FROM AUTHOR]

Background: The urban freight transportation (UFT) system is an essential facilitator for the smooth functioning of city logistics. It also contributes significantly to transportation-related issues, such as vehicular congestion, pollution, accidents, infrastructure damage and other related problems. Objectives: This study aimed to understand and compare the urban freight traffic characteristics and their impact in two cities: Gothenburg, Sweden and Delhi, India, having high socio-economic differences. The findings of this study will be helpful for practitioners and policymakers in the development and successful implementation of UFT management policies. Method: Using the cordon count (traffic data), retailers' interviews (receivers' data) and freight vehicle drivers' interviews, UFT characteristics such as sector-specific contribution, trip characteristics, vehicular characteristics and negative impacts in terms of external cost to society are evaluated. This study also discusses the prediction of attracted trips in the study zone using freight trip attraction (models. Results: About 75% of the trips in Gothenburg and 92% of the trips in Delhi are made by light commercial and other small-sized vehicles. Gothenburg has formally organised sectors involved in freight vehicle movement; however, Delhi has informally organised sectors. Conclusion: The results revealed substantial differences in characteristics of freight trip operations in both the cities, compared with few similarities. Measures taken considering the specific local attributes of freight traffic and stakeholders' requirement may lead to a sustainable transportation system in cities. [ABSTRACT FROM AUTHOR]

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Background: The urban freight transportation (UFT) system is an essential facilitator for the smooth functioning of city logistics. It also contributes significantly to transportation-related issues, such as vehicular congestion, pollution, accidents, infrastructure damage and other related problems. Objectives: This study aimed to understand and compare the urban freight traffic characteristics and their impact in two cities: Gothenburg, Sweden and Delhi, India, having high socio-economic differences. The findings of this study will be helpful for practitioners and policymakers in the development and successful implementation of UFT management policies. Method: Using the cordon count (traffic data), retailers’ interviews (receivers’ data) and freight vehicle drivers’ interviews, UFT characteristics such as sector-specific contribution, trip characteristics, vehicular characteristics and negative impacts in terms of external cost to society are evaluated. This study also discusses the prediction of attracted trips in the study zone using freight trip attraction (models. Results: About 75% of the trips in Gothenburg and 92% of the trips in Delhi are made by light commercial and other small-sized vehicles. Gothenburg has formally organised sectors involved in freight vehicle movement; however, Delhi has informally organised sectors. Conclusion: The results revealed substantial differences in characteristics of freight trip operations in both the cities, compared with few similarities. Measures taken considering the specific local attributes of freight traffic and stakeholders’ requirement may lead to a sustainable transportation system in cities.

Automobile emissions in urban cities, such as Peru, are significant; however, there are no published studies of the effects of these emissions on PM2.5 (fine particulate matter) formation. This study aims to analyze the contributions of vehicle aerosol emissions to the surface mass concentration of PM2.5 in the Metropolitan Area of Lima and Callao (MALC), one of the most polluted cities in Latin America and the Caribbean (LAC) known to have high concentrations of PM2.5. In February 2018, we performed two numerical simulations (control and sensitivity) using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). We considered both trace gasses and aerosol emissions from on-road traffic for the baseline simulation (hereinafter referred to as “control”); gasses without particulate emissions from vehicles were considered for the sensitivity simulation (hereinafter referred to as WithoutAerosol). For control, the model’s performance was evaluated using in situ on-ground PM2.5 observations. The results of the predicted PM2.5 concentration, temperature, and relative humidity at 2 m, with wind velocity at 10 m, indicated the accuracy of the model for the control scenario. The results for the WithoutAerosol scenario indicated that the contributions of vehicular trace gasses to secondary aerosols PM2.5 concentrations was 12.7%; aerosol emissions from road traffic contributed to the direct emissions of fine aerosol (31.7 ± 22.6 µg/m3).

Motor vehicles operating on the road are a significant source of Particulate Matter (PM) emissions depending on the fuels used in the vehicles. Gasoline and Diesel vehicles are directly responsible for the tailpipe PM emissions (specifically PM2.5: particles ≤ 2.5 µm), known as primary PM2.5 emissions. The other major direct emissions from the vehicles, which include volatile organic compounds (VOCs), and nitrogen oxides (NOx) contribute to the formation of secondary organic PM, also known as secondary organic aerosols (SOA), through some inter-related chemical reactions. The SOAs are highly toxic and contribute to a portion of total PM emissions. In this research, emission scenarios of both primary PM2.5 and SOA for a car-dependent expanding Australian city (Adelaide) were analyzed. The variability of traffic characteristics on road was considered and conducted a probabilistic emissions inventory for tailpipe primary PM2.5 and precursors, while statistical analysis of the probable chemical conversion ratios was considered for the SOA inventory. It was found that the tailpipe emissions from the vehicles were higher than the air quality standard, while the SOA contribution from the vehicles was not significantly high but contributed to the increase of total PM concentration. The analysis of the chemical transformation of SOA precursors justified the importance of conducting more detailed emissions modelling for sustainable urban air quality planning. [ABSTRACT FROM AUTHOR]

This study aimed at assessing the influence of vehicle traffic on spatial variation of ozone (O3) and its vehicular emission precursors in the air of Port Harcourt city. Sampling was carried out in ten (10) sites, eight (8) located within the high traffic density area (study sites) and two (2) located within the very low traffic density area (reference sites). The precursor pollutants measured were nitrogen dioxide (NO2), carbon monoxide (CO) and volatile organic compounds (VOCSs). Ozone and the precursor pollutants were measured in situ using AeroQUAL 500 series portable ambient air analyzer while traffic flow survey was achieved by direct counting. Measurements were carried out at morning, evening and off-peak traffic periods respectively. The mean concentrations of ozone and the precursor pollutants were significantly higher (p = 0.05) in the study sites than in the reference sites. Mean concentrations were higher at peak traffic periods than at off-peak traffic periods except for ozone that was higher at off-peak than at morning peak. There was significant correlation between traffic density and each of the pollutants including ozone. The spatial variability in concentration of pollutants was influenced by vehicular traffic. VOCs and NO2 levels were higher than the National Ambient Air Quality Standard (NAAQS) limit of 0.05 ppm and 0.04 - 0.06 ppm respectively, O3 concentration was below the standard limit (0.06 ppm) but was at the verge of exceeding. Traffic emission within the city was significant and could be mitigated through regular monitoring and control. [ABSTRACT FROM AUTHOR]

Levels of suspended particulate matter (PM) of both fractions PM10 and PM2.5 in ambient air were monitored in three areas of Gran La Plata: industrial, urban, and residential (2017–2019). Associated polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs) to PM were also determined and possible emission sources were identified. Assessment of health risk to PM exposure and associated compounds was realized. Results showed a decrease in levels of PM10 in each area along the period studied, especially in the industrial area. Decreases in PM2.5 levels were also observed in urban and residential areas over the years, although the trend is not as marked as with PM10 levels. Then, PM2.5 levels in the industrial area have remained practically constant. The 89% of both PM10 and PM2.5 annual mean exceeds the WHO reference values. The presence of most of the 16 US EPA priority PAHs studied was found with a detection frequency greater than 60% and it was possible to identify the importance of the contributions of vehicular emissions as predominant sources of PAH emission. From the calculations of the risk of contracting cancer throughout life (LCR), in the case of adults, the US EPA limits were not complied in the industrial and urban areas and in both fractions of PM. From the evaluation of the burden of disease (EBD), the calculated relative risks of mortality were very similar for the studied districts, being the relative risk in La Plata slightly lower, about 3–5%, than those in Berisso and Ensenada. [ABSTRACT FROM AUTHOR]

Urban air pollution caused by atmospheric aerosols has far-reaching implications on human health, economy, and climate. Using chemical transport models (CTMs) as inputs to the existing vehicle emission inventory (VEI) data in the metropolitan area of Lima and Callao (MALC) results in lower simulated PM 10 and PM 2.5 concentrations than the measured concentrations in MALC. Thus, the model needs to be improved to increase the accuracy of simulations. Numerical air pollution modeling using CTMs has rarely been studied in Peru. This study aimed to improve PM 10 and PM 2.5 concentration simulations using CTMs in Peru by calculating a new VEI. Subsequently, PM 10 and PM 2.5 simulations were conducted using the Brazilian Regional Atmospheric Modeling System (BRAMS) 5.2, which employs both VEI from a previous study (referred to as numerical simulation 1, NS1, serving as the control simulation) and the new VEI (resulting in NS2, NS3, and NS4, representing the sensitivity simulations). The results indicated that the sensitivity simulations conducted using the BRAMS 5.2 model effectively captured PM 10 and PM 2.5 concentrations, aligning closely with the measured data. The study provides an in-depth understanding of air quality dynamics that can assist in implementing strong policies and environmental management efforts to mitigate air pollution. • PM 10 and PM 2.5 level simulations were improved using chemical transport models. • PM 2.5 simulations were improved in the metropolitan area of Lima and Callao. • The simulated PM 10 concentrations were similar to the measured PM 10 concentrations. • Effectiveness of emissions inventory in enhancing PM simulation accuracy was tested. • The study can assist in implementing effective air pollution mitigation strategies. [ABSTRACT FROM AUTHOR]