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Associations between indoor air pollution from fine particulate matter (PM with aerodynamic diameter d p < 2.5 μm) and human health are poorly understood. Here, we analyse the concentration-response curves for fine and ultrafine PM, the gene expression, and the methylation patterns in human bronchial epithelial cells (BEAS-2B) exposed at the air-liquid interface (ALI) within a classroom in downtown Rome. Our results document the upregulation of aryl hydrocarbon receptor (AhR) and genes associated with xenobiotic metabolism (CYP1A1 and CYP1B1) in response to single exposure of cells to fresh urban aerosols at low fine PM mass concentrations within the classroom. This is evidenced by concentrations of ultrafine particles (UFPs, dp < 0.1 μm), polycyclic aromatic hydrocarbons (PAH), and ratios of black carbon (BC) to organic aerosol (OA). Additionally, an interleukin 18 (IL-18) down-regulation was found during periods of high human occupancy. Despite the observed gene expression dysregulation, no changes were detected in the methylation levels of the promoter regions of these genes, indicating that the altered gene expression is not linked to changes in DNA methylation and suggesting the involvement of another epigenetic mechanism in the gene regulation. Gene expression changes at low exposure doses have been previously reported. Here, we add the possibility that lung epithelial cells, when singly exposed to real environmental concentrations of fine PM that translate into ultra-low doses of treatment, may undergo epigenetic alteration in the expression of genes related to xenobiotic metabolism. Our findings provide a perspective for future indoor air quality regulations. We underscore the potential role of indoor UFPs as carriers of toxic molecules with low-pressure weather conditions, when rainfall and strong winds may favour low levels of fine PM. [Display omitted] • No significant correlation was found between PM 1 and gene regulation of BEAS-2B cell. • AhR and CYP upregulation was linked to fresh urban aerosol and low condensation sink. • IL-18 was down-regulated during periods of high human occupancy. • The promoter methylation levels of AhR, CYP1A1, CYP1B1 and IL-18 were not changes. [ABSTRACT FROM AUTHOR]

The 31st FISU Summer World University Games (SWUG) was held in Chengdu, southwestern China, from July 22 to August 8, 2023. A series of control measures were carried out to ensure good air quality during the SWUG, providing an opportunity to investigate the atmospheric behaviors of light-absorbing aerosols under such a substantial disturbance caused by the control measures. To assess the impacts of emission controls on primary pollutants, a field campaign was conducted at a rural site in Chengdu to investigate the characterization of equivalent black carbon (eBC). The changes of eBC concentrations before, during, and after the SWUG were characterized. The sources of eBC were resolved, and the impacts of atmospheric processes on the absorption capacity were also investigated. During the SWUG, the eBC concentration decreased by 12.1 % and 25.3 % compared with those before and after the SWUG. A fossil fuel combustion (eBC ff) and a biomass burning (eBC bb) originated eBC were resolved using the aethalometer model. Both eBC ff and eBC bb decreased during the SWUG, indicating the effectiveness of control measures. After the SWUG, the influence of biomass burning emissions became more and more significant, and the contribution of brown carbon (BrC) to light absorption at 370–660 nm increased by 52, 19, 7, 6, and 17 % compared to those during the SWUG. As the biomass burning emitted aerosols aged, the absorption Ångström exponent and b abs (BrC 370nm) decreased gradually, which was mainly due to the photobleaching of the chromophores during the daytime. eBC ff was mainly affected by strong wind, while high eBC bb concentration was mainly attributed to the gradual accumulation of biomass-burning emissions near the observation site. The results show the significant reduction of eBC with the implementation of the air pollution mitigation campaign, and provide insights on the impacts of atmospheric processes on BC optical properties during summertime. [Display omitted] • Black carbon reduced significantly during the Summer World University Games. • Fossil fuel combustion and biomass burning were main sources of black carbon. • Higher absorption Ångström exponent was attributed to biomass-burning emissions. • Brown carbon absorption coefficient reduced as biomass-burning organic aerosol aged. [ABSTRACT FROM AUTHOR]

High uncertainty in optical properties of black carbon (BC) involving heterogeneous chemistry has recently attracted increasing attention in the field of atmospheric climatology. To fill the gap in BC optical knowledge so as to estimate more accurate climate effects and serve the response to global warming, it is beneficial to conduct site-level studies on BC light absorption enhancement (E abs) characteristics. Real-time surface gas and particulate pollutant observations during the summer and winter over Wuhan were utilized for the analysis of E abs simulated by minimum R squared (MRS), considering two distinct atmospheric conditions (2015 and 2017). In general, differences in aerosol emissions led to E abs differential behaviors. The summer average of E abs (1.92 ± 0.55) in 2015 was higher than the winter average (1.27 ± 0.42), while the average (1.11 ± 0.20) in 2017 summer was lower than that (1.67 ± 0.69) in winter. E abs and R BC (representing the mass ratio of non-refractory constituents to elemental carbon) constraints suggest that E abs increased with the increase in R BC under the ambient condition enriched by secondary inorganic aerosol (SIA), with a maximum growth rate of 70.6% in 2015 summer. However, E abs demonstrated a negative trend against R BC in 2017 winter due to the more complicated mixing state. The result arose from the opposite impact of hygroscopic SIA and absorbing OC/irregular distributed coatings on amplifying the light absorbency of BC. Furthermore, sensitivity analysis revealed a robust positive correlation (R > 0.9) between aerosol chemical compositions (including sulfate, nitrate, ammonium and secondary organic carbon), which could be significantly perturbed by only a small fraction of absorbing materials or restructuring BC through gaps filling. The above findings not only deepen the understanding of BC, but also provide useful information for the scientific decision-making in government to mitigate particulate pollution and obtain more precise BC radiative forcing. [Display omitted] • In 2015, E abs was high in summer and low in winter. • Compared to 2015, the seasonal pattern of E abs reversed in 2017. • E abs demonstrated a negative trend against R BC in 2017 winter. • The positive correlation between E abs and SIA was affected by BC mixing-state diversity. • Aqueous phase heterogeneous reactions dominated the generation of SIA. [ABSTRACT FROM AUTHOR]

Glacial bodies in the Peruvian Andes Mountains store and supply freshwater to hundreds of thousands of people in central Peru. Atmospheric black carbon (BC) is known to accelerate melting of snow and ice, in addition to contributing to air pollution and the health of people. Currently there is limited understanding on the sources and temporal variability of BC in valley and mountain environments in Peru. To address this problem, this study combined surface observations of BC collected during 2022–2023 with WRF model simulations and HYSPLIT trajectories to analyze the dispersion and sources of BC in valley and high elevation environments and the associated local atmospheric circulations. Results show high BC concentrations are associated with the valley-mountain wind system that occurs on both sides of the Huaytapallana mountain range. A pronounced circulation occurs on the western slopes of Huaytapallana when concentrations of BC increase during daylight hours, which transports atmospheric pollutants from cities in the Mantaro River Valley to the Huaytapallana mountain range. Low concentrations of BC are associated with circulations from the east that are channeled by the pronounced ravines of the Andes-Amazon transition. On average, during the season of highest BC concentrations (July–November), the relative contributions of fossil fuels are dominant to biomass burning at the valley observatory and are slightly lower at the Huaytapallana observatory. These results demonstrate the need to promote mitigation actions to reduce emissions of BC and air pollution associated with forest fires and local anthropogenic activity. [Display omitted] [ABSTRACT FROM AUTHOR]

Through a comprehensive investigation into the historical profiles of black carbon derived from ice cores, the spatial distributions of light-absorbing impurities in snowpit samples, and carbon isotopic compositions of black carbon in snowpit samples of the Third Pole, we have identified that due to barriers of the Himalayas and remove of wet deposition, local sources rather than those from seriously the polluted South Asia are main contributors of light-absorbing impurities in the inner part of the Third Pole. Therefore, reducing emissions from residents of the Third Pole themselves is a more effective way of protecting the glaciers of the inner Third Pole in terms of reducing concentrations of light-absorbing particles in the atmosphere and on glaciers. [Display omitted] • LAPs deposited on glaciers of the inner TP are primarily sourced from the TP itself. • The Himalayas serve as barrier of transport LAPs from South Asia into inner TP. • Atmosphere of the inner TP remains largely devoid of long-range transported LAPs. [ABSTRACT FROM AUTHOR]

Air pollution control protocols and policies formulated for PM 2.5 and PM 10 (particulate matter [PM] with an aerodynamic diameter of ≤2.5 and 10 μm), however, such protocols and policies have not been available for black carbon (BC). A growing number of studies have evaluated the association between long-term exposure to ambient air pollution with BC and PM and pre-eclampsia. We applied a meta-analysis to estimate pooled odds ratios (ORs) and 95 % confidence intervals (CIs) based on four exposure windows (first/second/third trimester and entire pregnancy). 24 studies meeting our selection criteria (8 for BC, 21 and 15 for PM 2.5 and PM 10) were finally included after screening studies published up to June 22, 2023. An increase of 1 μg/m3 BC during the second trimester and entire pregnancy were associated with a 16 % (OR: 1.16, 95 % CI: [1.02, 1.32]) and a 15 % (OR: 1.15, 95 % CI: [1.03, 1.29]) increased risk of pre-eclampsia, respectively. A 10 μg/m3 increase in second-trimester exposure to PM 2.5 and PM 10 was associated with a 1 % (OR: 1.01, 95 % CI: [1.00, 1.03]) and a 5 % (OR: 1.05, 95 % CI: [1.01, 1.10]) increased risk of pre-eclampsia. An 11 % (OR: 1.11, 95 % CI: [1.03, 1.21]) increased risk of pre-eclampsia was found to be associated with a 10 μg/m3 increase in PM 10 exposure during the entire pregnancy. The results support the potential effect of exposure to ambient particulate pollutants on risk of pre-eclampsia and emphasize the necessity of strategies and protocols for controlling BC. Greater efforts in controlling ambient particulate pollution and especially BC are needed in order to prevent pregnant women from developing pre-eclampsia. [Display omitted] • Separate pre-eclampsia from hypertensive disorders of pregnancy independently. • Estimate the potential effects of BC, PM 2.5 , and PM 10 on the risk of pre-eclampsia. • Update the inconsistent results of previous studies and reviews. • Emphasize the necessity of controlling particulate matter especially black carbon. [ABSTRACT FROM AUTHOR]

Black carbon (BC) constitutes a pivotal component of atmospheric aerosols, significantly impacting regional and global radiation balance, climate, and human health. In this study, we evaluated BC data in two prominent atmospheric composition reanalysis datasets: the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) and the Copernicus Atmosphere Monitoring Service (CAMS), and analyzed the causes of their deviations. This assessment is based on observational data collected from 34 monitoring stations across China from 2006 to 2022. Our research reveals a significant and consistent decline in BC concentrations within China, amounting to a reduction exceeding 67.33%. However, both MERRA-2 and CAMS reanalysis data fail to capture this declining trend. The average annual decrease of BC in MERRA-2 from 2006 to 2022 is only 0.06 μg/m3 per year, while the BC concentration in CAMS even increased with an average annual value of 0.014 μg/m3 per year. In 2022, MERRA-2 had overestimated BC concentration by 20% compared to observational data, while CAMS had overestimated it by approximately 66%. In the regional BC concentration analysis, the data quality of the reanalysis data is better in the South China (R M = 0.59, R C = 0.53), followed by the North China (R M = 0.50, R C = 0.42). Reanalysis BC data in Northwest China and the Tibetan Plateau are difficult to use for practical analysis due to their big difference with observation. In a comparison of the anthropogenic BC emissions inventory used in the two atmospheric composition reanalysis datasets with the Multi-resolution Emission Inventory model for Climate and air pollution research (MEIC) emissions inventory, we found that: Despite the significant decline in China's BC emissions, MERRA-2 still relies on the 2006 emissions inventory, while CAMS utilizes emission inventories that even show an increasing trend. These factors will undoubtedly lead to greater deviations between reanalysis and observational data. [Display omitted] • The BC of MERRA-2 and CAMS was comprehensively evaluated for the first time in China. • Neither MERRA-2 nor CAMS reproduce observed BC downward trend from 2006 to 2022. • The use of the BC emission inventory with wrong annual trend is an important reason. [ABSTRACT FROM AUTHOR]

The Himalayan region is adversely affected by the increasing anthropogenic emissions from the adjacent Indo-Gangetic plain. However, source apportionment studies for the Himalayan region that are crucial for estimating CO concentration, are grossly insufficient, to say the least. It is in this context that our study reported here assumes significance. This study utilizes five years (2014–2018) of ground-based observations of eBC and multiple linear regression framework (MLR) to estimate CO and segregate its fossil fuel and biomass emission fractions at a high-altitude (1958 m) site in the Central Himalayas. The results show that MERRA2 always underestimates the observed CO; MOPITT has a high monthly difference ranging from −32% to +57% while WRF-Chem simulations underestimate CO from February to June and overestimate in other months. In contrast, CO estimated from MLR replicates diurnal and monthly variations and estimates CO with an r2 > 0.8 for 2014–2017. The CO predicted during 2018 closely follows the observed variations, and its mixing ratios lie within ±17% of the observed CO. The results reveal a unimodal diurnal variation of CO, CO ff (ff: fossil fuel) and CO bb (bb: biomass burning) governed by the boundary layer evolution and upslope winds. CO ff has a higher diurnal amplitude (39.1–67.8 ppb) than CO bb (5.7–33.5 ppb). Overall, CO ff is the major contributor (27%) in CO after its background fraction (58%). CO bb fraction reaches a maximum (28%) during spring, a period of increased agricultural and forest fires in Northern India. In comparison, WRF-Chem tracer runs underestimate CO bb (−38% to −98%) while they overestimate the anthropogenic CO during monsoon. This study thus attempts to address the lack of continuous CO monitoring and the need to segregate its fossil fuel and biomass sources, specifically over the Central Himalayas, by employing a methodology that utilizes the existing network of eBC observations. [Display omitted] • MLR CO estimates perform better than WRF-Chem, MOPITT and MERRA2. • CO observations infer higher fossil fuel (27%) contribution than biomass (15%). • Regional fire lead to highest biomass CO in spring (28%). • Significant contribution of background CO (58%), followed by fossil fuel (27%). [ABSTRACT FROM AUTHOR]

Black carbon (BC) emissions, resulting from the incomplete combustion of carbonaceous fuels, have been extensively linked to adverse impacts on air quality, climate change, and public health. Nevertheless, there is currently a lack of a comprehensive analysis that integrates activity-based BC emissions inventory and scenario analysis at the national/regional, sectoral, and sub-sectoral levels in Pakistan. This study aims to fill this gap by conducting a comprehensive evaluation of Pakistan's BC emissions inventory for 2021 along projecting emissions until 2050 under the reference emission scenario (RES) and the accelerated reduction scenario (ARS) using the GAINS modeling framework to assess the potential impact of mitigation measures. This study takes a unique approach by considering commonly overlooked sources of BC emissions, such as kerosene lighting, brick kilns, diesel generator sets, and natural gas flaring, which are not typically included in conventional analyses. National BC emissions in 2021 were estimated at 181 kt, with residential combustion being the major contributor, accounting for more than half (108 kt) of the total emissions. The transport, industry, waste, agriculture, power plants, and fuel conversion sectors contributed 26.1 kt, 20.1 kt, 10.7 kt, 8.9 kt, 6.0 kt, and 0.9 kt, respectively. We anticipate that the total BC emissions in Pakistan will reach 201 kt under the RES and 41 kt under the ARS scenario by the year 2050. The ARS achieves substantial BC reductions by the adoption of cleaner fuels, improved biomass stoves, end-of-pipe emission control technologies with higher removal efficiencies, and implementing a ban on the open burning of waste and crop residues. This study underscores the considerable potential for reducing BC emissions across various sectors in Pakistan over the next three decades. [Display omitted] • For 2021, Pakistan's BC emissions inventory showed total emissions at 181 kt. • The GAINS model is used to integrate new BC emissions source categories. • Modeling BC emissions mitigation in reference and accelerated reduction scenarios. • Advanced measures may cut three-quarters of BC emissions in the next 30 years. • Clean cooking and advanced measures will cut significant BC emissions in Pakistan. [ABSTRACT FROM AUTHOR]

The imprints of fireworks displays on the adjacent water body were investigated from the perspective of cogeneration of black carbon, metals and perchlorate (ClO 4 −). In particular, the mixing and dissipation of ClO 4 − were studied at Oak Lake, Lincoln, Nebraska, following fireworks displays in 2015 and 2016. Following the display, ClO 4 − concentration in the water increased up to 4.3 μg/L and 4.0 μg/L in 2015 and 2016, respectively. A first-order model generally provided a good fit to the measured perchlorate concentrations from which the rate of dissipation was estimated as 0.07 d−1 in 2015 and 0.43 d−1 in 2016. SEM images show imprints of soot and metal particles in aerosol samples. EDS analysis of the lake sediment confirmed the presence of Si, K, Ca, Zn and Ba, most of which are components of fireworks. The δ13C range of −7.55‰ to −9.19‰ in the lake water system closely resembles fire-generated carbon. Cogeneration of black carbon and metal with perchlorate was established, indicating that ClO 4 − is an excellent marker of fireworks or a burning event over all other analyzed parameters. Future microcosmic, aggregation and column-based transport studies on black carbon in the presence of perchlorate and metals under different environmental conditions will help in developing transport and fate models for perchlorate and black carbon particles. Image 1 • A fireworks display cogenerated black carbon, metal and perchlorate (ClO 4 −). • ClO 4 − in adjacent lake water increased up to 4.3 μg/L after the fireworks. • ClO 4 − dissipation rate constants were 0.07 d−1 in 2015 and 0.43 d−1 in 2016. • A δ13C range of −7.55‰ to −9.19‰ in lake water resembles fire-generated carbon. • Findings indicate ClO 4 − is an excellent marker of fireworks or a burning event. Black carbon, metal and perchlorate are cogenerated from fireworks display followed by perchlorate dissipation through dilution and pseudo first-order decay. [ABSTRACT FROM AUTHOR]

Abstract Despite the ban on new manufacture and commercial use of PCBs, municipal sewer systems continue to serve as ongoing secondary sources for contamination in receiving water bodies. Ongoing PCB sources have made it difficult to achieve desired recovery after implementation of sediment cleanup efforts. We report on a 16-month surveillance to determine the inputs, fate, and export of PCBs within a municipal waste collection/treatment system by strategic sampling of the freely-dissolved and biosolids-associated PCBs. The total PCBs entering the treatment plant was found to be 170 g/day of which 100 g/day exited the plant associated with the biosolids and 5.2 g/day was discharged in the form of freely-dissolved PCBs in the effluent. A net loss of 68 g/day was calculated for the plant, attributable to volatilization and biodegradation. Freely dissolved PCBs in the treated effluent was an order of magnitude higher than the water quality criteria for the protection of human health through fish consumption and found to be a major contributor to the dissolved concentration in the receiving river. Predicted bioaccumulation in fish from dissolved PCBs in the effluent exceeded the threshold for human consumption. The biosolids, currently land-applied as fertilizer, contained an average PCB concentration of 760 μg/kg. The sludge produced in this treatment plant is processed in large anaerobic digesters and changes to the homolog distribution point to some microbial dechlorination. Application of biosolids to clean agricultural soil resulted in a 6-fold increase in PCB levels in the earthworm E. fetida which could be eliminated by the amendment of 1% by weight of activated carbon. Graphical abstract Image 1 Highlights • Fate of dissolved and particle-associated PCBs in an urban wastewater treatment plant. • Passive sampling used to accurately measure freely dissolved PCBs in wastewater. • 58% of the 170 g/d PCBs entering the plant is retained in the biosolids. • Biosolids application to soil results in 6-fold increase in PCB uptake in earthworms. • PCBs in the final effluent exceeds human health risk threshold for fish consumption. PCBs exiting a large City wastewater treatment plant through biosolids and effluent water pose significant risk of exposure to the ecosystem. [ABSTRACT FROM AUTHOR]

Abstract Ambient ultrafine black carbon (uBC) can potentially cross blood-brain barrier, however, very little is currently known about the effects they may have on central nervous system. This study aimed to explore the roles of autophagy in Alzheimer-like pathogenic changes promoted by uBC in SH-SY5Y cells. We firstly found uBC could cause cytotoxicity and oxidative stress in SH-SY5Y cells. Additionally we found uBC initiated progressive development of Alzheimer's disease (AD) associated features, mainly including neuro-inflammation and phosphorylation of tau protein (p-Tau) accumulation. Meanwhile, autophagy process was activated by uBC probably through phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway. RNA interference and autophagosome-lysosome fusion inhibitor were applied to block autophagy process at different stages. Autophagy dysfunction at the initial membrane expansion stage could aggravate p-Tau accumulation and other Alzheimer-like changes in SH-SY5Y cells promoted by uBC. However, autophagy inhibition at the final stage could alleviate p-Tau accumulation caused by uBC. This suggested that inhibition of the infusion of autophagosome and lysosome could possibly activate ubiquitination degradation pathway to regulate p-Tau equilibrium in SH-SY5Y cells. Our findings further raise the concerns about the effects of uBC on the risk of AD and indicate potential roles of autophagy in early Alzheimer-like pathogenic changes caused by ambient uBC. Graphical abstract Image 1 Highlights • Ultrafine black carbon (uBC) caused early Alzheimer-like pathogenic changes. • Autophagy related to these Alzheimer-like pathogenic changes induced by uBC. • Autophagy inhibition at initial membrane expansion stage aggravated p-Tau accumulation. • Autophagy dysfunction at final stage alleviate p-Tau accumulation. Autophagy regulated Alzheimer-like pathogenic changes promoted by uBC. [ABSTRACT FROM AUTHOR]

Abstract Aerosol black carbon (BC) is the second strongest contributor to global warming, after CO 2 , and it is linked to many adverse health effects. A sampling campaign of 15 months was carried out in León (Spain) in order to evaluate the scavenging of BC with an ensemble aethalometer-disdrometer. The aethalometer provides the concentration of equivalent black carbon (eBC), and the disdrometer, the raindrop size distribution. A total of seventy-five rain events were studied and in 73% of them there was an effective (eBC initial > eBC final) scavenging, with a mean decrease of 48 ± 37% in long rain events (>8 h) and 39 ± 38% in short rain events. The scavenging of BC is strongly related to its source. Thus, the scavenging coefficient (SC) mean value of the BC from fossil fuel (eBC ff) for short and long rain events was 5.1 10−5 and 1.3 10−5 s−1, respectively. For the BC from biomass burning (eBC bb), the SC values were 1.6 10−4 and 2.8 10−5 s−1 in short and long events, respectively. There was a significant positive correlation between the SC and the number of drops with diameters between 0.375 and 2.5 mm. Rain scavenging of eBC was analyzed depending on the air mass origin obtaining an effective scavenging for air masses from Atlantic, Arctic and Africa. A linear model (R2 = 0.72) was built to estimate the ΔeBC values with variables from an aethalometer, a disdrometer and a weather station: eBC concentration before rain, swept volume and precipitation accumulated. A Kolmogorov-Smirnov statistical test confirmed the goodness of fit of the model to the measured data. Graphical abstract Image 1 Highlights • Hourly measures were taken of black carbon and rain during 15 months in León, Spain. • 70% of the rain events showed an effective scavenging (37% eBC decrease). • The scavenging coefficient for short rain events is 3 times the one for long events. • The scavenging was different according to specific BC source. • A model for rain scavenging of BC with aethalometer and disdrometer data was built. The combination of aethalometer and disdrometer measurements reveals that the scavenging of BC depends strongly on the BC source (biomass burning or fossil fuel combustion). [ABSTRACT FROM AUTHOR]

Abstract Based on the ground-measurements and MERRA-2 (Modern-Era Retrospective Analysis for Research and Applications, Version 2) reanalysis data, the temporal-spatial variation of black carbon (BC) in Beijing and the affecting factors were investigated. According to the ground-measured BC concentration in November months of 2014, 2015 and 2016, the before-heating period in November 2014 showed the lowest BC concentration as a result of the efficient emission controls for the Asia-Pacific Economic Cooperation (APEC) meeting. Except for November 2014, the BC mass concentration during the heating periods was notably lower than the before-heating periods in November 2015 and 2016. Wind speed and relative humidity appeared to be two important meteorological parameters affecting BC pollution. The MERRA-2 BC concentration was validated through comparison with the continuous ground BC measurements in 2015 and 2016, affirming its reliability in demonstrating the large scale and long term variations of the ground BC concentration. The MERRA-2 BC spatial distribution, the potential source regions determined by concentration weighted trajectory (CWT) analysis, and the regional emission inventories were combined to reveal the potential source regions and source types of BC in Beijing. Transportation emission in Beijing and residential emissions in the neighboring regions such as Hebei appeared to be important sources of BC in Beijing. According to the historical trends of MERRA-2 BC concentration and typical fossil fuel consumption (1980–2017), local coal and coke are no longer the major factor affecting the BC concentration, instead, liquid fuels such as gasoline, kerosene, and diesel may highly contribute to the BC pollution in Beijing in recent years. Regional transport of BC may have also contributed to the loading of BC in Beijing. Open biomass burning may be a non-negligible factor for the short-term variation of BC in the atmosphere. Graphical abstract Image 1 Highlights • The MERRA-2 data proved to be reliable in describing long term and large scale BC variation. • Transportation emission in Beijing and residential emissions in neighboring regions affected BC pollution in Beijing. • Regional energy structure and strategy adjustment reduced BC in Beijing. Comprehensive analyses of BC concentration, meteorological conditions, emission inventories, and typical fossil fuel consumption history revealed the affecting factors of BC in Beijing. [ABSTRACT FROM AUTHOR]

Accurately estimating annual average daily traffic (AADT) on minor roads is essential for assessing traffic-related air pollution (TRAP) exposure, particularly in areas where most people live. Our study assessed the direct and indirect external validity of three methods used to estimate AADT on minor roads in Melbourne, Australia. We estimated the minor road AADT using a fixed-value approach (assuming 600 vehicles/day) and linear and negative binomial (NB) models. The models were generated using road type, road importance index, AADT and distance of the nearest major road, population density, workplace density, and weighted road density. External measurements of traffic counts, as well as black carbon (BC) and ultrafine particles (UFP), were conducted at 201 sites for direct and indirect validation, respectively. Statistical tests included Akaike information criterion (AIC) to compare models' performance, the concordance correlation coefficient (CCC) for direct validation, and Spearman's correlation coefficient for indirect validation. Results show that 88.5% of the roads in Melbourne are minor, yet only 18.9% have AADT. The performance assessment of minor road models indicated comparable performance for both models (AIC of 1,023,686 vs. 1,058,502). In the direct validation with external traffic measurements, there was no difference between the three methods for overall minor roads. However, for minor roads within residential areas, CCC (95% confidence interval [CI]) values were −0.001 (−0.17; 0.18), 0.47 (0.32; 0.60), and 0.29 (0.18; 0.39) for the fixed-value approach, the linear model, and the NB model, respectively. In the indirect validation, we found differences only on UFP where the Spearman's correlation (95% CI) for both models and fixed-value approach were 0.50 (0.37; 0.62) and 0.34 (0.19; 0.48), respectively. In conclusion, our linear model outperformed the fixed-value approach when compared against traffic and TRAP measurements. The methodology followed in this study is relevant to locations with incomplete minor road AADT data. [Display omitted] • Minor roads contribute to air pollution but their traffic volume is largely unknown. • Direct external validation of models showed good performance in residential areas. • Indirect external validation of ultrafine particle models showed good performance. • The models can estimate minor roads' traffic volume in large cities. • The method is relevant to locations with incomplete minor road traffic volume data. [ABSTRACT FROM AUTHOR]

Recent recommendations given by WHO include systematic measurements of ambient particle number concentration and black carbon (BC) concentrations. In India and several other highly polluted areas, the air quality problems are severe and the need for air quality related information is urgent. This study focuses on particle number emissions and BC emissions of passenger cars that are technologically relevant from an Indian perspective. Particle number and BC were investigated under real-world conditions for driving cycles typical for Indian urban environments. Two mobile laboratories and advanced aerosol and trace gas instrumentation were utilized. Our study shows that passenger cars without exhaust particle filtration can emit in real-world conditions large number of particles, and especially at deceleration a significant fraction of particle number can be even in 1.5–10 nm particle sizes. The mass concentration of exhaust plume particles was dominated by BC that was emitted especially at acceleration conditions. However, exhaust particles contained also organic compounds, indicating the roles of engine oil and fuel in exhaust particle formation. In general, our study was motivated by serious Indian air quality problems, by the recognized lack of emission information related to Indian traffic, and by the recent WHO air quality guidance; our results emphasize the importance of monitoring particle number concentrations and BC also in Indian urban areas and especially in traffic environments where people can be significantly exposed to fresh exhaust emissions. [Display omitted] • Real-world particles emissions of passenger cars were studied down to 1.5 nm • Nanoparticle emissions were detected especially at deceleration conditions • Black carbon emissions were detected especially at accelerations • Chemical composition of particles revealed the roles of fuel and engine oil [ABSTRACT FROM AUTHOR]

Elucidating the associations between environmental noise and heart rate variability (HRV) would be beneficial for the prevention and control of detrimental cardiovascular changes. Obese people have been found to manifest heightened susceptibility to the adverse effects of noise on HRV. However, the underlying mechanisms remain unclear. Based on 53 normal-weight and 44 obese young adults aged 18–26 years in Beijing, China, this study aimed to investigate the role of obesity-related cardiometabolic indicators for associations between short-term environmental noise exposure and HRV in the real-world context. The participants underwent personal noise exposure and ambulatory electrocardiogram monitoring using portable devices at 5-min intervals for 24 continuous hours. Obesity-related blood pressure, glucose and lipid metabolism, and inflammatory indicators were subsequently examined. Generalized mixed-effect models were used to estimate the associations between noise exposure and HRV parameters. The C-peptide, homeostasis model assessment of insulin resistance (HOMA-IR), and leptin levels were higher in obese participants compared to normal-weight participants. We observed amplified associations between short-term noise exposure and decreases in HRV among participants with higher C-peptide, HOMA-IR, and leptin levels. For instance, a 1 dB(A) increment in 3 h-average noise exposure level preceding each measurement was associated with changes of −0.20% (95%CI: −0.45%, 0.04%) and −1.35% (95%CI: −1.85%, −0.86%) in standard deviation of all normal to normal intervals (SDNN) among participants with lower and higher C-peptide levels, respectively (P for interaction <0.05). Meanwhile, co-existing fine particulate matter (PM 2.5) could amplify the associations between noise and HRV among obese participants and participants with higher C-peptide, HOMA-IR, and leptin levels. The more apparent associations of short-term exposure to environmental noise with HRV and the effect modification by PM 2.5 may be partially explained by the higher C-peptide, HOMA-IR, and leptin levels of obese people. [Display omitted] • Obese people are susceptible to the adverse effects of environmental noise on HRV. • Obesity is related to higher C-peptide, HOMA-IR, and leptin levels. • Obesity-related cardiometabolic changes aggravate the effects of noise on HRV. • Obesity-related cardiometabolic changes amplify the effect modification by PM 2.5. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) and black carbon (BC) often coexist in PM 2.5 because both form during the incomplete combustion of organic matter. These compounds are regarded as hazardous air pollutants with potential health effects, including respiratory and cardiovascular effects. In this study, to evaluate the health risks of PAHs and BC at an urban site in northern Taiwan, 16 priority PAHs and BC, identified by the United States Environmental Protection Agency, were analyzed and quantified in PM 2.5 to determine their concentrations, their relationship with each other, and their likely sources. The results indicated that the mean concentrations of total PAHs and BC were 0.91 ng m−3 and 0.97 μg m−3, respectively, with a significant positive correlation between them, indicating the same emission sources. The results also indicated that fossil fuel combustion and traffic emissions were primary contributors to PAHs, with wood and biomass combustion playing a less prominent role. Among these 16 priority PAHs, benzo[ a ]pyrene, dibenz[ a , h ]anthracene, benzo[ b ]fluoranthene, and indeno[1,2,3- cd ]pyrene served as major carcinogenic compounds, accounting for 89.0% of the total carcinogenic toxicity. Thus, the lifetime excess cancer risk resulting from PAH exposure was estimated as 8.03 × 10−6, indicating a potential carcinogenic risk to human health at the sampling site. Overall, this study highlights the need for future mitigation policies for traffic emissions and fossil fuel combustion for reducing the local emissions of BC and co-produced PAHs in northern Taiwan. [Display omitted] • Total PAHs showed a significant positive correlation with BC in ambient PM 2.5. • The ratio of total PAHs to BC in ambient PM 2.5 was approximately 1 ng μg-1. • PAHs were from fossil fuel combustion, traffic exhaust, and biomass burning. [ABSTRACT FROM AUTHOR]

Abstract Air pollution remains a major global public health and environmental issue. We assessed the levels of PM 2.5 and delineated the major sources in Makkah, Saudi Arabia. Fine particulate matter (PM 2.5) sampling was performed from February 26, 2014–January 27, 2015 in four cycles/seasons. Samples were analyzed for black carbon (BC) and trace elements (TEs). PM 2.5 source apportionment was performed by computing enrichment factors (EFs) and positive matrix factorization (PMF). Backward-in time trajectories were used to assess the long-range transport. Significant seasonal variations in PM 2.5 were observed, Spring: 113 ± 67.1, Summer: 88.3 ± 36.4, Fall: 67.8 ± 24, and Winter: 67.6 ± 36.9 μg m−3. The 24-h PM 2.5 exceeded the WHO (25 μg m−3) and Saudi Arabia's (35 μg m−3) guidelines, with an air quality index (AQI) of "unhealthy to hazardous" to human health. Most delta–C computations were below zero, indicating minor contributions from bio-mass burning. TEs were primarily Si, Ca, Fe, Al, S, K and Mg, suggesting major contributions from soil (Si, Ca, Fe, Al, Mg), and industrial and vehicular emissions (S, Ca, Al, Fe, K). EF defined two broad categories of TEs as: anthropogenic (Cu, Zn, Eu, Cl, Pb, S, Br and Lu), and earth-crust derived (Al, Si, Na, Mg, Rb, K, Zr, Ti, Fe, Mn, Sr, Y, Cr, Ga, Ca, Ni and Ce). Notably, all the anthropogenic TEs can be linked to industrial and vehicular emissions. PMF analysis defined four major sources as: vehicular emissions, 30.1%; industrial-mixed dust, 28.9%; soil/earth-crust, 24.7%; and fossil-fuels/oil combustion, 16.3%. Plots of wind trajectories indicated wind direction and regional transport as major influences on air pollution levels in Makkah. In collusion, anthropogenic emissions contributed >75% of the observed air pollution in Makkah. Developing strategies for reducing anthropogenic emissions are paramount to controlling particulate air pollution in this region. Graphical abstract Makkah air quality Image 1 Highlights • PM 2.5 concentrations exceeded the WHO guidelines by a factor of about 4. • A detailed source apportionment of air pollution in Makkah. • Anthropogenic sources (local vehicular and regional industrial emissions) contribute over 75% of the total PM 2.5 emissions. • Regional transport of industrial emissions is significant to Makkah's air pollution levels. [ABSTRACT FROM AUTHOR]

Black carbon and total organic carbon (TOC) along with organochlorines (OCs) were analyzed in soils from four sampling zones of Lesser Himalayan Region based on source proximity/anthropogenic influences along the altitude. CTO-375 method was used for BC analysis while OCs were analyzed by GC-MS/MS system. BC and TOC ranged between 0.16–1.77 and 6.8–41.3 mg g −1 while those of OCPs and PCBs ranged between 0.69 and 5.77 and 0.12–2.55 ng g −1 , respectively. ∑ DDTs were the dominant (87.9%) among OCPs while tri- and tetra- (65.5%) homologue groups among PCBs. Hexa-PCBs, however also showed higher contribution (20.4%) in the region. Source diagnostic ratios of DDE + DDD/DDT (0.1–1.53) indicated both fresh and old input while α- HCH/ γ- HCH (0.19–2.49) showed presence of lindane in the region. Higher concentration of OCs were observed in Zone C at altitudinal range of 737–975 masl that are close to the human influences and potential sources of POPs. The results of linear regression analysis revealed potential input of BC in soil distribution of OC concentrations in the region. [ABSTRACT FROM AUTHOR]

The effects of fine particles (PM 2.5 ) on asthma have been widely confirmed by epidemiological research studies. However, a limited number of studies have investigated the relationship between exposure to different PM 2.5 components and asthma. We characterized the PM 2.5 components in a suburban site of central Taiwan and conducted a time-stratified case-crossover study to elaborate the effects of daily concentration of each PM 2.5 component on asthma outpatient visits. We retrieved asthma outpatient claims for individuals less than 20 years old with a residential address in the Shalu district, Taiwan, from the National Health Insurance Research Database during 2000–2010. Multiple linear regression models were used to back extrapolate the historic concentration of individual components of PM 2.5 from 2000 through to 2010, including black carbon (BC) and eight ions, namely, sulfate, nitrate (NO 3 − ), ammonium, chloride, potassium (K + ), magnesium, calcium, sodium. The odds ratio (OR) with a 95% confidence interval (CI) of individual PM 2.5 components on asthma was estimated by conditional logistic regression. A total of 887 asthma outpatient visits with individuals who have an average age of 7.96 ± 3.88 years were selected. After adjusting for confounders, we found an interquartile range (IQR) increase in BC level, an IQR increase in NO 3 − level, and an IQR increase in K + level that were all associated with the increased risk of asthma outpatient visits from the current day (OR = 1.18, 95% CI: 1.05–1.34; OR = 1.11, 95% CI: 1.01–1.21; and OR = 1.16, 95% CI: 1.04–1.30, respectively). The effects of these components on asthma were stronger in the cold season than in the warm season. However, we did not find any lagging effects. The results suggest that exposure to NO 3 − , BC, and K + derived from industry-related combustion or motor vehicles emission sources may increase the risk of asthma outpatient visits, particularly during the cold season. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate associations between cardiovascular effects and urban ambient particle constituents using an in vivo crossover experimental design. Ambient particles were introduced to an exposure chamber for whole-body exposure of WKY rats, where the particulate matter with an aerodynamic diameter of <2.5 μm (PM 2.5 ) mass concentration, particle number concentration, and black carbon (BC) were monitored. Organic carbon (OC), elemental carbon (EC), and soluble ions of PM 2.5 were determined. In a crossover design, rats were exposed to ambient particles or high-efficiency particle arrestance (HEPA)-filtered control air for 7 days following a 7-day washout interval. The crossover exposure between particles and HEPA-filtered air was repeated 4 times. Radiotelemetric data on blood pressure (BP) [systolic BP (SBP), diastolic BP (DBP), pulse pressure (PP), and mean arterial pressure (MAP)], heart rate (HR), and heart rate viability (HRV) were subsequently obtained during the entire study. Exposure to the PM 2.5 mass concentration was associated with decreases in the SBP, DBP, MAP, and HR ( p < 0.05), whereas no significant changes in the BP or HR occurred with the particle number or black carbon. For HRV, the ln 5-min standard deviation of the normal-to-normal (NN) interval (LnSDNN) and the ln root mean square of successive differences in adjacent NN intervals (LnRMSSD) were positively associated with the PM 2.5 mass concentration ( p < 0.05). There were no significant effects of the particle number concentration or BC on HRV. Alterations in the HR were associated with OC, EC, Na + , Cl − , and NO 3 − . Cl − was associated with the DBP, MAP, HR, SDNN, and RMSSD. NO 3 − was correlated with the SBP, MAP, HR, SDNN, and RMSSD. In conclusion, we observed cardiovascular responses to ambient particles in vivo using a crossover design which can reduce animal use in future environmental studies. [ABSTRACT FROM AUTHOR]

Mitigating black carbon (BC) emissions from various combustion sources has been considered an urgent policy issue to address the challenges of climate change, air pollution and health risks. Vehicles contribute considerably to total anthropogenic BC emissions and urban BC concentrations. Compared with heavy-duty diesel vehicles, there is much larger uncertainty in BC emission factors for light-duty passenger vehicles (LDPVs), in particular for gasoline LDPVs, which warrants further studies. In this study, we employed the dynamometer and the Aethalometer (AE-51) to measure second-by-second BC emissions from eight LDPVs by engine technology and driving cycle. The average BC emission factors under transient cycles (e.g., ECE-15, New European Driving Cycle, NEDC, Worldwide Harmonized Light Vehicles Test Cycle, WLTC) are 3.6–91.5 mg/km, 7.6 mg/km and 0.13–0.58 mg/km, respectively, for diesel ( N = 3 ), gasoline direct injection (GDI) ( N = 1 ) and gasoline port-fuel injection (PFI) engine categories ( N = 4 ). For gasoline PFI LDPVs, the instantaneous emission profiles show a strong association of peak BC emissions with cold-start and high-speed aggressive driving. Such impacts lead to considerable BC emission contributions in cold-start periods (e.g., the first 47 s–94 s) over the entire cycle (e.g., 18–76% of the NEDC and 13–36% of the WLTC) and increased BC emission factors by 80–440% under the WLTC compared to the NEDC. For diesel BC emissions, the size distribution exhibits a typical unimodal pattern with one single peak appearing approximately from 120 to 150 nm, which is largely consistent with previous studies. Nevertheless, the average mass ratios of BC to particle mass (PM) range from 0.38 to 0.54 for three diesel samples, representing substantial impacts from both driving and engine conditions. The significant discrepancy between gasoline BC emission factors obtained from tailpipe exhaust versus ambient conditions suggest that more comparative measurements and fine-grained simulations should be designed and implemented to address this discrepancy. [ABSTRACT FROM AUTHOR]

Semivolatile organic compounds (SVOCs) represent a dominant category of secondary organic aerosol precursors that are increasingly included in air quality models. In the present study, an experimental system was developed and applied to a light-duty diesel engine to determine the emission factors of particulate SVOCs (pSVOCs) and nonvolatile particulate matter (PM) components at dilution ratios representative of ambient conditions. The engine was tested under three steady-state operation modes, using ultra-low-sulfur diesel (ULSD), three types of pure biodiesels and their blends with ULSD. For ULSD, the contribution of pSVOCs to total particulate organic matter (POM) mass in the engine exhaust ranged between 21 and 85%. Evaporation of pSVOCs from the diesel particles during dilution led to decreases in the hydrogen to carbon ratio of POM and the PM number emission factor of the particles. Substituting biodiesels for ULSD could increase pSVOCs emissions but brought on large reductions in black carbon (BC) emissions. Among the biodiesels tested, tallow/used cooking oil (UCO) biodiesel showed advantages over soybean and canola biodiesels in terms of both pSVOCs and nonvolatile PM emissions. It is noteworthy that PM properties, such as particle size and BC mass fraction, differed substantially between emissions from conventional diesel and biodiesels. [ABSTRACT FROM AUTHOR]

Measuring black carbon (BC) is critical to understand the impact of combustion aerosols on air quality and climate change. In this study, BC was measured in 2014 at a unique community formed with rapid economic development and urbanization in an urban-rural fringe area of Beijing. Hourly BC concentrations were 0.1–33.5 μg/m 3 with the annual average of 4.4 ± 3.7 μg/m 3 . BC concentrations had clear diurnal, weekly, and seasonal variations, and were closely related with atmospheric visibility. The absorption coefficient of aerosols increased while its contribution to extinction coefficient decreased with the enhancement of PM 2.5 concentration. The high mass absorption efficiency (MAE) of EC was attributed to a combination of coal combustion, vehicular emission and rapidly coating by water-soluble ions and organic carbon (OC). BC concentrations followed a typical lognormal pattern, with over 88% samples in 0.1–10.0 μg/m 3 . Low BC levels were mostly bounded up with winds from north and northwest. Coal combustion and biomass burning were closely associated with severe haze pollution events. Firework discharge had significant UV absorption contribution. During the Asia-Pacific Economic Cooperation (APEC) forum in November 2014, air quality obviously improved due to various control strategies. [ABSTRACT FROM AUTHOR]

Atmospheric black carbon (BC) is an important pollutant for both air quality and Earth's energy balance. Estimates of BC climate forcing remain highly uncertain, e.g., due to the mixing with non-absorbing components. Non-absorbing aerosols create a coating on BC and may thereby act as a lens which may enhance the light absorption. However, this absorption enhancement is poorly constrained. To this end a two-step solvent dissolution protocol was employed to remove both organic and inorganic coatings, and then investigate their effects on BC light absorption. Samples were collected at a severely polluted urban area, Jinan, in the North China Plain (NCP) during February 2014. The BC mass absorption cross-section (MAC) was measured for the aerosol samples before and after the solvent-decoating treatment, and the enhancement of MAC ( E MAC ) from the coating effect was defined as the ratio. A distinct diurnal pattern for the enhancement was observed, with E MAC 1.3 ± 0.3 (1 S.D.) in the morning, increasing to 2.2 ± 1.0 in the afternoon, after that dropping to 1.5 ± 0.8 in the evening-night. The BC absorption enhancement primarily was associated with urban-scale photochemical production of nitrate and sulfate aerosols. In addition to that, regional-scale haze plume with increasing sulfate levels strengthened the absorption enhancement. These observations offer direct evidence for an increased absorption enhancement of BC due to severe air pollution in China. [ABSTRACT FROM AUTHOR]

Microplastic particles are increasingly being discovered in diverse habitats and a host of species are found to ingest them. Since plastics are known to sorb hydrophobic organic contaminants (HOCs) there is a question of what risk of chemical exposure is posed to aquatic biota from microplastic-associated contaminants. We investigate bioavailability of polychlorinated biphenyls (PCBs) from polypropylene microplastic by measuring solid-water distribution coefficients, gut fluid solubilization, and bioaccumulation using sediment invertebrate worms as a test system. Microplastic-associated PCBs are placed in a differential bioavailability framework by comparing the results to several other natural and anthrogenic particles, including wood, coal, and biochar. PCB distribution coefficients for polypropylene were higher than natural organic materials like wood, but in the range of lipids and sediment organic carbon, and smaller than black carbons like coal and biochars. Gut fluid solubilization potential increased in the order: coal < polypropylene < biochar < wood. Interestingly, lower gut fluid solubilization for polypropylene than biochar infers that gut fluid micelles may have solubilized part of the biochar matrix while bioaccessibility from plastic can be limited by the solubilizing potential of gut fluids dependent on the solid to liquid ratio or renewal of fluids in the gut. Biouptake in worms was lower by 76% when PCBs were associated with polypropylene compared to sediment. The presence of microplastics in sediments had an overall impact of reducing bioavailability and transfer of HOCs to sediment-ingesting organisms. Since the vast majority of sediment and suspended particles in the environment are natural organic and inorganic materials, pollutant transfer through particle ingestion will be dominated by these particles and not microplastics. Therefore, these results support the conclusion that in most cases the transfer of organic pollutants to aquatic organisms from microplastic in the diet is likely a small contribution compared to other natural pathways of exposure. [ABSTRACT FROM AUTHOR]

Based on a near real–time 10 km × 10 km resolution black carbon (BC) concentration dataset, this study investigated the spatial patterns, trend variations, and drivers of BC concentrations in China from 2001 to 2019 with spatial analysis, trend analysis, hotspot clustering, and multiscale geographically weighted regression (MGWR). The results indicate that Beijing–Tianjin–Hebei, the Chengdu–Chongqing agglomeration, Pearl River Delta, and East China Plain were the hotspot centers of BC concentration in China. From 2001 to 2019, the average rate of decline in BC concentrations across China was 0.36 μg/m3/year (p < 0.001), with BC concentrations peaking around 2006 and sustaining a decline for the next decade or so. The rate of BC decline was higher in Central, North, and East China than in other regions. The MGWR model revealed the spatial heterogeneity of the influences of different drivers. A number of enterprises had significant effects on BC in East, North, and Southwest China; coal production had strong effects on BC in Southwest and East China; electricity consumption had better effects on BC in Northeast, Northwest, and East China than in other regions; the ratio of secondary industries had the greatest effects on BC in North and Southwest China; and CO 2 emissions had the strongest effects on BC in East and North China. Meanwhile, the reduction of BC emissions from the industrial sector was the dominant factor in the decrease of BC concentration in China. These findings provide references and policy prescriptions for how cities in different regions can reduce BC emissions. [Display omitted] • The regions of high BC concentration in China are located east of the Hu line. • The BC decreased at a rate of 0.36 μg/m3 (p < 0.001) per year from 2001 to 2019 in China. • Multiscale geographically weighted regression indicated a spatial heterogeneity in driving factors. • The pronounced decrease in BC emissions is the dominant contributor to the falling BC concentrations. [ABSTRACT FROM AUTHOR]

The mixing of black carbon (BC) with secondary materials is a major uncertainty source in assessing its radiative forcing. However, current understanding of the formation and evolution of various BC components is limited, particularly in the Pearl River Delta, China. This study measured submicron BC-associated nonrefractory materials and the total submicron nonrefractory materials using a soot particle aerosol mass spectrometer and a high-resolution time-of-flight aerosol mass spectrometer, respectively, at a coastal site in Shenzhen, China. Two distinct atmospheric conditions were also identified to further explore the distinctive evolution of BC-associated components: polluted period (PP) and clean period (CP). Comparing the components of two particles, we found that more-oxidized organic factor (MO-OOA) prefers to form on BC during PP rather CP. The formation of MO-OOA on BC (MO-OOA BC) was affected by both enhanced photochemical processes and nocturnal heterogeneous processes. Enhanced photo-reactivity of BC, photochemistry during the daytime, and heterogeneous reaction at nighttime were potential pathways for MO-OOA BC formation during PP. The fresh BC surface was favorable for the formation of MO-OOA BC. Our study shows the evolution of BC-associated components under different atmospheric conditions, which should be considered in regional climate models to improve the assessment of the climate effects of BC. [Display omitted] • More-oxidized organic components were preferentially formed on BC during polluted period. • More-oxidized organic components on BC tended to be formed through photochemistry. • Aqueous-phase reaction promoted the formation of more-oxidized organic on BC. • The surface of fresh BC was favorable for formation of more-oxidized organic components. [ABSTRACT FROM AUTHOR]

Black carbon (BC) is a product of incomplete or inefficient combustion and may be associated with a variety of adverse effects on human health. The objective of this study was to analyze the association between various mortalities and long-/short-term exposure to BC as an independent pollutant. In this systematic review, we searched 4 databases for original research in English up to 6th October 2022, that investigated population-wide mortality due to BC exposure. We pooled mortality estimates and expressed them as relative risk (RR) per 10 μg/m3 increase in BC. We used a random-effect model to derive the pooled RRs. Of the 3186 studies identified, 29 articles met the eligibility criteria, including 18 long-term exposure studies and 11 short-term exposure studies. In the major meta-analysis and sensitivity analysis, positive associations were found between BC and total mortality and cause-specific disease mortalities. Among them, the short-term effects of BC on total mortality, cardiovascular disease mortality, respiratory disease mortality, and the long-term effects of BC on total mortality, ischemic heart disease mortality, respiratory disease mortality and lung cancer mortality were found to be statistically significant. The heterogeneity of the meta-analysis results was much lower for short-term studies than for long-term. Few studies were at a high risk of bias in any domain. The certainty of the evidence for most of the exposure-outcome pairs was moderate. Our study showed a significantly positive association between short-/long-term BC exposure and various mortalities. We speculate that BC has a higher adverse health effect on the respiratory system than on the cardiovascular system. This is different from the effect of PM 2.5. Therefore, more studies are needed to consider BC as a separate pollutant, and not just as a component of PM 2.5. [Display omitted] • We performed a meta-analysis of the association between black carbon and mortality. • Short-term exposure to BC had significantly adverse health effects. • Long-term exposure to BC increased total and many cause-specific disease mortalities. • Impact of BC on respiratory system is higher than that on cardiovascular system. [ABSTRACT FROM AUTHOR]

Brown carbon (BrC), as an important light-absorbing aerosol, significantly impacts regional and global climate. Vehicle emission is a nonnegligible source of BrC, but the optical properties of BrC emitted from vehicles remain poorly understood. This study evaluates the absorption Ångström exponent (AAE) of traffic-related light-absorbing aerosols (i.e., AAE Tr) and the absorption emission factor (EF abs) of vehicular BrC via chassis dynamometer tests and a road tunnel measurement in Tianjin, China. AAE Tr are estimated as 0.98–1.33 and 1.11 ± 0.001 for tested vehicles and on-road vehicle fleet, respectively. The AAE of vehicular BrC (AAE BrC) is 3.83 ± 0.092 for on-road vehicle fleet. The vehicle technology updates effectively reduce the EF abs of vehicular BrC. Among the four tested China 5 and China 6 gasoline vehicles in the chassis dynamometer tests, BrC EF abs of China 5 gasoline direct injection vehicle is the highest, while China 6 mixing fuel injection vehicle exhibits the lowest EF abs. The BrC EF abs of on-road vehicle fleet at 370 nm wavelength are 0.081 ± 0.0058 m2 kg−1 for mixed fleet, 0.074 ± 0.018 m2 kg−1 for gasoline vehicles (GVs), and 1.66 ± 0.71 m2 kg−1 for diesel vehicles (DVs) in the tunnel measurement. EF abs of GV fleet in the road tunnel is higher than China 5 and China 6 vehicles, as China 1–4 vehicles accounted for 26.8% of the total vehicle fleet in the tunnel. EF abs of vehicular BrC are lower than those from biomass burning and coal combustion emissions. The light absorption of BrC from GVs and DVs accounts for 7.2 ± 2.1% and 1.5 ± 0.77% of total traffic-related absorption at 370 nm, respectively. Our study provides optical features of BrC from vehicle source and could contribute to estimating the impacts of vehicular aerosol emissions on global and regional climate change. [Display omitted] • EF abs of vehicular BrC were obtained via laboratory tests and field measurements. • Traffic AAE and AAE BrC for on-road vehicle fleet were 1.11 and 3.83, respectively. • Contribution of BrC to traffic-related light absorption at 370 nm wavelength was 8.6%. [ABSTRACT FROM AUTHOR]

Black carbon (BC) can be transported over long distances and is an important trigger of climate warming and glacier melting at remote high mountains and polar regions. It is normally assumed that the variation of BC flux in remote regions is dominated by its emissions. However, after a comprehensive investigation of potential influencing factors on temporal variations of BC from ice cores of the Himalayas, this short communication shows that in addition to BC emissions, contributions from dust storms and precipitation are also important (up to 56% together) in regulating the variation of BC deposition flux and concentrations derived from remote Himalayan ice core measurements. Therefore, besides BC emissions, the influence of precipitation and BC transported by dust storms should also be considered to better quantify the lifetime and behavior of BC during its long-range transport from source to sink regions as well as to quantify the climatic effects of BC over remote Himalayan glaciers. [Display omitted] • Potential factors influence BC deposition at the Himalayan glacier were studied. • BC emission does not dominate BC deposition at the Himalayan glacier. • Precipitation and dust storms are important factors influence BC deposition. [ABSTRACT FROM AUTHOR]

The effects of exposure to black carbon (BC) on various diseases remains unclear, one reason being potential exposure misclassification following modelling of ambient air pollution levels. Urinary BC particles may be a more precise measure to analyze the health effects of BC. We aimed to assess the risk of prediabetes and metabolic syndrome (MetS) in relation to urinary BC particles and ambient BC and to compare their associations in 5453 children from IDEFICS/I. Family cohort. We determined the amount of BC particles in urine using label-free white-light generation under femtosecond pulsed laser illumination. We assessed annual exposure to ambient air pollutants (BC, PM 2.5 and NO 2) at the place of residence using land use regression models for Europe, and we calculated the residential distance to major roads (≤250 m vs. more). We analyzed the cross-sectional relationships between urinary BC and air pollutants (BC, PM 2.5 and NO 2) and distance to roads, and the associations of all these variables to the risk of prediabetes and MetS, using logistic and linear regression models. Though we did not observe associations between urinary and ambient BC in overall analysis, we observed a positive association between urinary and ambient BC levels in boys and in children living ≤250 m to a major road compared to those living >250 m away from a major road. We observed a positive association between log-transformed urinary BC particles and MetS (OR per unit increase = 1.72, 95% CI = 1.21; 2.45). An association between ambient BC and MetS was only observed in children living closer to a major road. Our findings suggest that exposure to BC (ambient and biomarker) may contribute to the risk of MetS in children. By measuring the internal dose, the BC particles in urine may have additionally captured non-residential sources and reduced exposure misclassification. Larger studies, with longitudinal design including measurement of urinary BC at multiple time-points are warranted to confirm our findings. [Display omitted] • Levels of urinary BC levels were higher in children living ≤250 m to major road. • Positive association between urinary BC particles and metabolic syndrome. • Positive association between ambient BC & MetS in children living ≤250 m to major road. [ABSTRACT FROM AUTHOR]

Black carbon (BC) is released into the atmosphere in large quantities from different emission sources each year and poses a serious threat to human health. These BC possessed a variety of characteristics and different mediation abilities for the reactive oxygen species (ROS) generation. In this study, we collected BC (i.e., diesel BC, coal BC and wood BC) from three typica emission sources, and examined their mediation abilities to the oxidation of glutathione (GSH). Results showed that all three BC significantly promoted the GSH oxidation, and the mediation efficiencies were as follows: diesel BC > coal BC > wood BC. In comparison with the water-soluble fraction, the mediation abilities of three BC mainly came from their solid phase fractions. In the coal BC and wood BC systems, the oxidation of GSH was attributed to the catalysis of transition metals in BC. By contrast, the transition metals, phenolic –OH and persistent free radicals in diesel BC were identified as the active sites responsible for the GSH oxidation. In addition, the graphitic surface of diesel BC could synergize with these active sites to accelerate the oxidation of GSH. Under the catalysis of BC, dissolved oxygen was first reduced to ROS (O 2 •− and H 2 O 2) and then caused the GSH oxidation. These findings not only help to better assess the adverse health effects of different BC, but also deepen the understanding of the reaction mechanisms. [Display omitted] • Three black carbon (BC) significantly promoted the glutathione (GSH) oxidation. • The mediation efficiencies decreased in the order: diesel BC > coal BC > wood BC. • Three BC mediated O 2 to form reactive oxygen species and caused the GSH oxidation. • Transition metals were the active sites for GSH oxidation in coal BC and wood BC. • Active sites in diesel BC were transition metals, phenolic –OH and persistent free radicals. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the levels and phenomenology of equivalent black carbon (eBC) at the city center of Augsburg, Germany (01/2018 to 12/2020). Furthermore, the potential health risk of eBC based on equivalent numbers of passively smoked cigarettes (PSC) was also evaluated, with special emphasis on the impact caused by the COVID19 lockdown restriction measures. As it could be expected, peak concentrations of eBC were commonly recorded in morning (06:00–8:00 LT) and night (19:00–22:00 LT) in all seasons, coinciding with traffic rush hours and atmospheric stagnation. The variability of eBC was highly influenced by diurnal variations in traffic and meteorology (air temperature (T), mixing-layer height (MLH), wind speed (WS)) across days and seasons. Furthermore, a marked "weekend effect" was evidenced, with an average eBC decrease of ∼35% due to lower traffic flow. During the COVID19 lockdown period, an average ∼60% reduction of the traffic flow resulted in ∼30% eBC decrease, as the health risks of eBC exposure was markedly reduced during this period. The implementation of a multilinear regression analysis allowed to explain for 53% of the variability in measured eBC, indicating that the several factors (e.g., traffic and meteorology) may contribute simultaneously to this proportion. Overall, this study will provide valuable input to the policy makers to mitigate eBC pollutant and its adverse effect on environment and human health. [Display omitted] • Regression analysis model allowed to explain for 53% of eBC levels. • T, WS, MLH, and traffic density are main drivers for eBC levels. • An average about 60% reduction of the traffic flow resulted in ca. 30% eBC decrease. • Health risk due to ambient eBC was reduced by about 34% during the lockdown period. [ABSTRACT FROM AUTHOR]

The fate of hydrophobic organic compounds in aquatic environment are largely determined by their exchange at sediment-water interface, which is highly dynamic and subject to rapidly evolving environmental conditions. In turn, environmental conditions may be governed by both physicochemical parameters and anthropogenic events. To examine the importance of various impact factors, passive sampling devices were deployed at the seafloor of Hailing Bay, an urbanized estuarine bay in Guangdong Province of South China to measure the sediment-water diffusion fluxes of several metabolites of dichlorodiphenyltrichloroethane (DDT), p,p ′-DDE, p,p ′-DDD and o,p ′-DDD. The physicochemical properties of water (temperature, pH, salinity and dissolved oxygen) and surface sediment (sediment organic matter, physical composition, pH, water content, colony forming unit and catalase activity) were also measured. The results showed that the diffusion fluxes of o,p ′-DDD, p,p ′-DDD and p,p ′-DDE at sites A1 and A2 near a fishing boat maintenance facility ranged from 0.42 to 4.73 ng m −2 d −1 (from sediment to overlying water), whereas those at offshore sites varied between −0.03 and −3.02 ng m −2 d −1 (from overlying water to sediment), implicating A1 and A2 as the sources of the target compounds. The distribution patterns of the diffusion fluxes of the target compounds were different from those of water and sediment parameters (water temperature, salinity, sediment texture, pH, colony forming unit and catalase activity) at six sampling sites. This finding suggested that none of these parameters were critical in dictating the sediment-water diffusion fluxes. Besides, decreases in the contents of kerogen and black carbon by 6.7% and 11% would enhance the diffusion fluxes of the target compounds by 11–14% and 12–23%, respectively, at site A1, indicating that kerogen and black carbon were the key factors in mediating the sediment–water diffusion fluxes of DDT-related compounds in field environments. [ABSTRACT FROM AUTHOR]

Gas flaring is a prominent source of VOCs, CO, CO 2 , SO 2 , PAH, NO X and soot (black carbon), all of which are important pollutants which interact, directly and indirectly, in the Earth’s climatic processes. Globally, over 130 billion cubic metres of gas are flared annually. We review the contribution of gas flaring to air pollution on local, regional and global scales, with special emphasis on black carbon (BC, “soot”). The temporal and spatial characteristics of gas flaring distinguishes it from mobile combustion sources (transport), while the open-flame nature of gas flaring distinguishes it from industrial point-sources; the high temperature, flame control, and spatial compactness distinguishes gas flaring from both biomass burning and domestic fuel-use. All of these distinguishing factors influence the quantity and characteristics of BC production from gas flaring, so that it is important to consider this source separately in emissions inventories and environmental field studies. Estimate of the yield of pollutants from gas flaring have, to date, paid little or no attention to the emission of BC with the assumption often being made that flaring produces a smokeless flame. In gas flares, soot yield is known to depend on a number of factors, and there is a need to develop emission estimates and modelling frameworks that take these factors into consideration. Hence, emission inventories, especially of the soot yield from gas flaring should give adequate consideration to the variation of fuel gas composition, and to combustion characteristics, which are strong determinants of the nature and quantity of pollutants emitted. The buoyant nature of gas flaring plume, often at temperatures in the range of 2000 K, coupled with the height of the stack enables some of the pollutants to escape further into the free troposphere aiding their long-range transport, which is often not well-captured by model studies. [ABSTRACT FROM AUTHOR]

Black carbon (BC) and PM 2.5 were studied for nine years from 2005 to 2013 in the Beijing urban area. The overall weekly average mass concentrations of BC and PM 2.5 were 4.3 and 66.8 μg/m³. PM 2.5 annual means of the nine years are around 2 times of the standard (GB3095-2012) in China, and are 5–7 times higher than the WHO standard. The Beijing Olympic Games in 2008 was a milestone to mitigate aerosol pollution. Temporal distribution of BC shows a distinct declining trend, and annual mean mass concentrations of PM 2.5 after 2008 were lower than those before 2008 but increased from 2011 to 2013. Wind rose plots show that high BC concentrations are usually associated with low wind speed of northeastern or southwestern winds, generally causing poor visibility. Governmental mitigation measures such as traffic restriction despite increased motor vehicle numbers and gasoline consumption and industry relocation with declining consumption of coal and coke were successful in reducing BC emissions. Annual mean of BC was reduced by 38% in 2013 compared to 2005. However, BC contamination in Beijing is still severe when compared to other urban areas around the world. [ABSTRACT FROM AUTHOR]

Black carbon (BC) and carbon monoxide (CO) at different model levels from the Copernicus Atmosphere Monitoring Service (CAMS) reanalysis were comprehensively evaluated against observations performed simultaneously on both surface and mountain sites in winter and summer in the North China Plain for the first time. CAMS could capture the seasonal difference in BC and CO emission on both sites but showed significant and persistent biases. Biases were high on the surface site and low on the mountain site for both seasons, implying the uncertainties in emission inventories used in the CAMS reanalysis which may have more influence near source. Biases were reduced and the correlation coefficient of CAMS BC with observed BC increased when two datasets were compared on a daily basis, which suggests daily or longer time averaged CAMS BC could be more suitable for trend analysis. Although CAMS could generally reproduce the distinct diurnal variation of BC and CO on both sites, the inaccurate representation of the daily evolution of planetary boundary layer (PBL) in model may bring more uncertainties to the concentration biases on surface from midnight to early morning. BC hydrophilic ratio from CAMS displayed large biases compared to observations with no seasonal difference on both sites, which was probably resulted from the initial emission state of BC hygroscopicity for all source types in model. Uncertainties in the removal processes and the simplified aging processes in model could further induce uncertainty in modelling BC hydrophilic ratio in the CAMS. These results could not only be referenced for the improvement on CAMS reanalysis but also facilitate model or trend analysis of BC and CO pollution by utilizing the CAMS reanalysis product from both short- and long-term perspectives, which will be beneficial to both the mitigation and policy-making on primary emissions in China. [Display omitted] • BC and CO from CAMS were evaluated for the first time in the NCP. • CAMS can capture the seasonal and diurnal variations of pollutants. • BC hydrophilic ratio from CAMS displayed large biases compared to observations. [ABSTRACT FROM AUTHOR]

Black carbon (BC), as one of the short-lived climate pollutants, is becoming more prominent contribution from non-road mobile source, especially for agricultural machinery (AM) in China. However, the understanding of BC emissions from AM is still not clear, and the BC emission factors (EFs) are also limited. In this study, we conducted real-world measurements on twenty AM to investigate the instantaneous BC emission characteristics and quantify BC EFs under the whole tillage processes. We find the instantaneous BC emissions and fuel consumptions are obvious differences and present good synchronization under different tillage processes. Multi-type (CO 2 -, fuel-, distance-, time-, and area-based) EFs of BC are developed, which are significantly affected by different tillage processes and emission standards of the used AM. While AM conducting rotary tillage, ploughing, harvest corn and harvest wheat on the same area of land, total BC emissions by using the China III emission standard AM will be reduced by 56%, 36%, 88%, and 87% than those by using China II emission standard AM, respectively. Furthermore, for corn and wheat production under the whole tillage processes, BC EFs are 16.90 (6.03–39.12) g/hm2 and 18.18 (5.91–38.69) g/hm2, CO 2 EFs are 112.64 (72.07–195.98) g/hm2 and 103.72 (71.47–167.02) g/hm2, respectively. We estimate the BC and CO 2 emissions from wheat and corn productions based on the average area-based EFs. The large fluctuation ranges of BC and CO 2 emissions in different tillage processes and the whole processes can reflect that the use of AM in China is uneven. It also indicates that there is a large space for BC and CO 2 emission reduction and optimization. Therefore, more attention should be paid to the control of BC and CO 2 emissions from AM. We believe that the recommended multi-type EFs are applicable for the quantification of BC emissions from AM in China and other countries. [Display omitted] • BC emissions of agricultural machinery under whole tillage processes are investigated. • Multi-type EFs of BC under different tillage processes are quantified. • BC EFs are significantly affected by different tillage processes and emission standards. • BC and CO 2 emissions from wheat and corn production are estimated. • There is a large space for BC and CO 2 emission reduction and optimization. [ABSTRACT FROM AUTHOR]

Black carbon (BC) exposure in China continues to be relatively high, prompting researchers to assess BC exposure levels using data from monitoring sites, satellite remote sensing, and models. However, data regarding the application of a combined strategy comprising the analysis of monitoring data and various types of data to simulate BC exposure levels are lacking. Hence, the current study seeks to estimate short- and long-term BC exposure levels by combining national monitoring data with data from the second Modern-Era Retrospective analysis for Research and Applications (MERRA-2). Furthermore, this study attempts to improve the spatio-temporal resolution of BC exposure levels using Bayesian maximum entropy (BME). The BME model performed well in terms of estimating short- (R2 = 0.74 and RMSE = 1.76 μg/m3) and long-term (R2 = 0.76 and RMSE = 1.3 μg/m3) exposure. Premature mortalities and economic losses were also assessed by applying localised concentration–response coefficients simulated in China. A total of 74,500 (95% confidence interval (CI): 23,900–124,500) and 538,400 (95% CI: 495,000–581,300) all-cause premature mortality cases were found to be associated with short- and long-term BC exposure, respectively. Meanwhile, short-term BC exposure was associated with economic losses ranging from 7.5 to 13.2 billion US dollars (USD) (1 USD = 6.36 RMB on January 19, 2022) based on amended human capital (AHC) and willingness to pay (WTP), accounting for 0.06%–0.1% of China's total gross domestic product (GDP) in 2017 (1.2 × 104 billion USD), respectively. The economic losses for long-term exposure varied from 53 to 93.2 billion USD based on AHC and WTP, accounting for 0.4%–0.8% of China's total GDP in 2017, respectively. [Display omitted] • Modelled black carbon (BC) exposure level was the highest in Sichuan Basin, China. • All-cause premature mortalities due to long-term BC exposure were 538,400 cases in 2017. • Economic losses due to BC exposure accounted for 0.8% of the 2017 GDP of China. [ABSTRACT FROM AUTHOR]

Exposure measurement error is an important source of bias in epidemiological studies. We assessed the validity of employing ambient (outdoor) measurements as proxies of personal exposures at individual levels focusing on fine particles (PM 2.5) and black carbon (BC)/elemental carbon (EC) on a global scale. We conducted a systematic review and meta-analysis and searched databases (ISI Web of Science, Scopus, PubMed, Ovid MEDLINE®, Ovid Embase, and Ovid BIOSIS) to retrieve observational studies in English language published from 1 January 2006 until 5 May 2021. Correlation coefficients (r) between paired ambient (outdoor) concentration and personal exposure for PM 2.5 or BC/EC were standardized as effect size. We used random-effects meta-analyses to pool the correlation coefficients and investigated the causes of heterogeneity and publication bias. Furthermore, we employed subgroup and meta-regression analyses to evaluate the modification of pooled estimates by potential mediators. This systematic review identified thirty-two observational studies involving 1744 subjects from ten countries, with 28 studies for PM 2.5 and 11 studies for BC/EC. Personal PM 2.5 exposure is more strongly correlated with ambient (outdoor) concentrations (0.63, 95% confidence interval [CI]: 0.57–0.68) than personal BC/EC exposure (0.49, 95% CI: 0.38–0.59), with significant differences in ṝ (0.14, 95% CI: 0.03–0.25; p < 0.05). The results demonstrated that the health status of participants was a significant modifier of pooled correlations. In addition, the personal to ambient (P/A) ratio for PM 2.5 and average ambient BC/EC levels were potential effect moderators of the pooled ṝ. The funnel plots and Egger's regression test indicated inevident publication bias. The pooled estimates were robust through sensitivity analyses. The results support the growing consensus that the validity coefficient of proxy measures should be addressed when interpreting results from epidemiological studies to better understand how strong health outcomes are affected by different levels of PM 2.5 and their components. [Display omitted] • Studies that investigated ambient/outdoor-personal exposure correlations were reviewed. • This review provides separate pooled estimates for PM 2.5 and BC/EC. • Significant differences in pooled correlations between PM 2.5 and BC/EC were shown. • Participants' health status and P/A ratios are modifiers of pooled correlations for PM 2.5. • Health status and ambient (outdoor) concentrations are modifiers of BC/EC correlations. [ABSTRACT FROM AUTHOR]

Black Carbon (BC) and Organic Carbon (OC) are the principal chemical aerosol components generated during combustion, both of which play a key role in air pollution, human health and climate change. Several studies of OC and BC have been conducted over India to assess the contribution from household and fossil fuel-based sources; however, studies on their emissions and their contribution from forest and cropland fires are quite limited. To address this issue, as part of this research, we derived a vegetation burning-based inventory of BC and OC aerosols over India at a resolution of 250 m × 250 m. Using a consumed biomass technique, we estimated emissions based on updated emission factor estimates. During the fire season in India (March–June), the mean OC and BC emissions were 2.1 ± 5.2 × 1013 kg per year and 1.8 ± 4.4 × 1012 kg per year, respectively. Andhra Pradesh had the highest total carbonaceous aerosol emissions during the study period. Forest fires were prevalent in the northeastern states, while agricultural fires were prevalent in Gujarat, Chhattisgarh, Odisha, Madhya Pradesh, Bihar, Tripura, Uttar Pradesh, and Andhra Pradesh. The previous inventory, conducted at a coarser resolution (25 km × 25 km), overestimated open burning by 5 Mt. Our results were highly correlated with global bottom-up model values, especially the Fire Inventory (FINN). Our analysis showed that vegetative burning contributed 80.32% of the total carbon stock, with agricultural burning being the largest source of vegetative burning. Based on these findings, measures and strategies to control agricultural burning which would reduce significantly the total emissions of BC and OC with implications to improvement in air quality, human health and climate should be planned. [Display omitted] • Agricultural burning dominates carbonaceous aerosol emissions in India. • Shrublands exhibit the highest inter-annual carbon stock change in India. • North-eastern states of India are worst affected by wildfires. • In India, vegetation burning contributes to 80.32% of carbon stock. • Global bottom-up inventories showed higher regional emissions in India. [ABSTRACT FROM AUTHOR]

Black carbon (BC) exports huge amounts of its derived DOM from terrestrial ecosystems annually through a variety of ways (i.e., erosion or runoff migration). The pyrolytic feedstock type and temperature resulted in DOM derived from highly condensed aromatic and non-aromatic BC. However, the behaviors of low aromatic BC-derived DOM at diverse leaching time are poorly understood. In this work, low aromatic BCs were prepared by pyrolysis corn straws at 250 °C, 350 °C and 450 °C. Extraction experiments for four leaching time (6 h, 10 h, 15 h and 21 h) were set up to simulate BC-derived DOM generative process in nature. The phytotoxicity of BC-derived DOM was evaluated via germination index (GI). Spectral characteristics were discussed to analyze the phytotoxicity variations of fluorescence components composition at different time, including the excitation-emission matrix-parallel factor, two-dimensional correlation spectra and Fourier transform infrared spectroscopy. The results suggested that low aromatic BC-derived DOM might contain aromatic phenolic compounds. A longer time contributed to accumulate the complex, hard-to-use organic matters, leading to lower GI. These results would supplement the dynamic spectral characteristics of low aromatic BC-derived DOM and its environmental risks during the leaching process. [Display omitted] • The dissolved organic matter of black carbon (BC) degraded with the leaching time. • BC derived dissolved organic matter (DOM) contained 0.95–5.87 mg/L phenols. • Leaching time promoted the dissolution of phenolic compounds from low-aromatic BC. • The accumulation of phenolic compounds in BC-derived DOM inhibited root growth. [ABSTRACT FROM AUTHOR]

Indoor particulate matter (PM) and black carbon (BC) are associated with adverse cardiopulmonary effect. However, the cumulative and interactive effects of the mixture of size-fractioned PMs and BC on cardiopulmonary function are not well understood, and the underlying biological mechanisms remain unclear. This repeated-measure study was conducted to assess the joint cardiopulmonary effect and metabolic mechanisms of multiple-size particles and BC among 46 children. PM 0.5 , PM 1 , PM 2.5 , PM 5 , PM 10 and BC were monitored for 5 weekdays. Cardiorespiratory function measurements and urine samples collection were conducted three times. Untargeted-metabolomics and meet-in-metabolite approach were applied to mechanism investigation. Bayesian machine kernel regression was adopted to analyze associations among PMs, cardiopulmonary function and metabolites. Lung function and heart rate variability significantly decreased with the increased PMs and BC co-exposure (p < 0.05). The effective particles were BC, PM 1-2.5 and PM 0.5 in turn. No interaction effects of different particles on cardiopulmonary function were observed at different lag days. BC-related glucose and fatty acid increase, and PM 1-2.5 -related branched-chain amino acid degradation were primarily observed. Other metabolisms were successively disturbed. The greatest joint effects of PMs and BC on metabolism were mainly at lag0 and lag01 day. They occurred earlier than the strongest effects on cardiopulmonary function, which were at lag01 and lag02 day. BC, PM 1-2.5 and PM 0.5 were mainly associated with cardiorespiratory indices by disturbing amino acids, glucose, lipid, isoflavone and purine metabolism. Mitochondrial productivity and antioxidation reduction are pivotal to the relevant metabolic alterations. More attention should be paid to BC and smaller-size PMs to control indoor PM pollution and its adverse effect on children. [Display omitted] • Co-exposure to indoor multiple PMs is related to adverse cardiopulmonary function. • Indoor PM 1-2.5 and BC are important for school children's adverse HRV changes. • BC, PM 0.5 , and PM 0.5-1 have adverse effects on blood pressure and lung function. • Mitochondrial productivity and antioxidation reduction are main metabolic changes. • BC and smaller PMs should be considered to further control indoor PM pollution. [ABSTRACT FROM AUTHOR]

In Asia, the evaluation of black carbon (BC) using global aerosol-transport models has been incomplete due to a lack of available measurements. Recently, new measurements and datasets at various Asian sites have become available for use in model validation. In this study, we compared the BC mass concentrations obtained by an aerosol-coupled global nonhydrostatic model adopting a uniform-grid system with in-situ measurements and other models over Asia. The results revealed that our model, as well as other global models, was unable to reproduce the observed BC values at most sites in China and India, most likely due to strong local hotspots. To overcome the inconsistency between the models and measurements, we developed a new aerosol-transport model using a stretched-grid system for high-resolution simulations with up to approximately 10 km grids. Our model can be used as a global-to-regional seamless aerosol-transport model for low to high horizontal resolution simulations. [ABSTRACT FROM AUTHOR]

Here, we provide Rock Eval and black carbon (BC) characteristics and polycyclic aromatic hydrocarbon (PAH) distribution coefficients (K D) for sediments from the Danube, Elbe, Ebro, and Meuse river basins. PAH desorption kinetic parameters were determined using sequential Tenax extractions. We show that residual carbon (RC) from Rock Eval analysis is an adequate predictor of fast, slow, and very slow desorbing fractions of 4-ring PAHs. RC correlated better than BC, the latter constituting only 7% of RC. A dual domain sorption model was statistically superior to a single domain model in explaining K D for low molecular weight PAHs, whereas the opposite was observed for high molecular weight PAHs. Because particularly the 4-ring PAHs are bioavailable and relevant from a risk assessment perspective and because their fast desorbing fractions correlate best with RC, we recommend RC as a relevant characteristic for river sediments. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNT) are strong sorbents for organic micropollutants, but changing environmental conditions may alter the distribution and bioavailability of the sorbed substances. Therefore, we investigated the effect of green algae (Chlorella vulgaris) on sorption of a model pollutant (diuron, synonyms: 3-(3,4-Dichlorophenyl)-1,1-dimethylurea, DCMU) to CNT (multi-walled purified, industrial grade, pristine, and oxidized; reference material: Diesel soot). In absence of algae, diuron sorption to CNT was fast, strong, and nonlinear (Freundlich coefficients: 105.79-106.24 μg/kgCNT-(μg/L)-n and 0.62-0.70 for KF and n, respectively). Adding algae to equilibrated diuron-CNT mixtures led to 15-20% (median) diuron re-dissolution. The relatively high amorphous carbon content slowed down ad-/desorption to/from the high energy sorption sites for both industrial grade CNT and soot. The results suggest that diuron binds readily, but -- particularly in presence of algae -- partially reversibly to CNT, which is of relevance for environmental exposure and risk assessment. [ABSTRACT FROM AUTHOR]

Air pollution has been accepted as an important contributor to asthma development and exacerbation. However, the evidence is limited in China. In this study, we investigated the acute effect of air pollution on asthma hospitalization in Shanghai, China. We applied over-dispersed generalized additive model adjusted for weather conditions, day of the week, long-term and seasonal trends. An interquartile range increase in the moving average concentrations of PM10, SO2, NO2 and BC on the concurrent day and previous day corresponded to 1.82%, 6.41%, 8.26% and 6.62% increase of asthmatic hospitalization, respectively. The effects of SO2 and NO2 were robust after adjustment for PM10. The associations appeared to be more evident in the cool season than in the warm season. Our results contribute to the limited data in the scientific literature on acute effects of air pollution on asthma in high exposure settings, which are typical in developing countries. [Copyright &y& Elsevier]