Black Carbon Research Articles

Long-term exposure to fine particulate matter constituents in relation to chronic kidney disease: evidence from a large population-based study in China.

The effects of long-term exposure to fine particulate matter (PM2.5) constituents on chronic kidney disease (CKD) are not fully known. This study sought to examine the association between long-term exposure to major PM2.5 constituents and CKD and look for potential constituents contributing substantially to CKD. This study included 81,137 adults from the 2018 to 2019 baseline survey of China Multi-Ethnic Cohort. CKD was defined by the estimated glomerular filtration rate. Exposure concentration data of 7 major PM2.5 constituents were assessed by satellite remote sensing. Logistic regression models were used to estimate the effect of each PM2.5 constituent exposure on CKD. The weighted quantile sum regression was used to estimate the effect of mixed exposure to all constituents. PM2.5 constituents had positive correlations with CKD (per standard deviation increase), with ORs (95% CIs) of 1.20 (1.02-1.41) for black carbon, 1.27 (1.07-1.51) for ammonium, 1.29 (1.08-1.55) for nitrate, 1.20 (1.01-1.43) for organic matter, 1.25 (1.06-1.46) for sulfate, 1.30 (1.11-1.54) for soil particles, and 1.63 (1.39-1.91) for sea salt. Mixed exposure to all constituents was positively associated with CKD (1.68, 1.32-2.11). Sea salt was the constituent with the largest weight (0.36), which suggested its importance in the PM2.5-CKD association, followed by nitrate (0.32), organic matter (0.18), soil particles (0.10), ammonium (0.03), BC (0.01). Sulfate had the least weight (< 0.01). Long-term exposure to PM2.5 sea salt and nitrate may contribute more than other constituents in increasing CKD risk, providing new evidence and insights for PM2.5-CKD mechanism research and air pollution control strategy.

Molecular-weight dependent promotion and competition effects of natural organic matter on dissolved black carbon removal by coagulation

Dissolved black carbon (DBC) is the ubiquitous component of dissolved organic matter pools with the high reactivity for disinfection byproducts formation. However, it is unknown that the influence of molecular weight (MW) of natural organic matter (NOM) on the DBC removal from potable water sources. Therefore, it was studied that the DBC removal by coagulation in the presence of the NOM with various molecular weights. The DBC removal was promoted due to the presence of NOM and the promotion degree decreased with decreasing MW of NOM. Furthermore, the removal ratio of humic-like component increased as the MW of NOM decreased, suggesting that the competition between DBC and NOM increased with decreasing MW. The functional groups after coagulation were the same with that before coagulation as the MW of NOM varied, suggesting that the molecular structure was not the key factor of influencing the DBC removal. This study will give the deep insight into the prediction of the DBC removal ratio by coagulation based on the MW of NOM in water sources.

South and Southeast Asia controls black carbon characteristics of Meili Snow Mountains in southeast Tibetan Plateau

South and Southeast Asia (SSA) emitted black carbon (BC) exerts potential effects on glacier and snow melting and regional climate change in the Tibetan Plateau. In this study, online BC measurements were conducted for 1 year at a remote village located at the terminus of the Mingyong Glacier below the Meili Snow Mountains. The Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) was used to investigate the contribution and potential effect of SSA-emitted BC. In addition, variations in the light absorption characteristics of BC and brown carbon (BrC) were examined. The results indicated that the annual mean concentration of BC was 415 ± 372 ngm−3, with the highest concentration observed in April (monthly mean: 930 ± 484 ngm−3). BC exhibited a similar diurnal variation throughout the year, with two peaks observed in the morning (from 8:00 to 9:00 AM) and in the afternoon (from 4:00 to 5:00 PM), with even lower values at nighttime. At a short wavelength of 370 nm, the absorption coefficient (babs) reached its maximum value, and the majority of babs values were < 20 Mm−1, indicating that the atmosphere was not overloaded with BC. At the same wavelength, BrC substantially contributed to babs, with an annual mean of 25.2 % ± 12.8 %. SSA was the largest contributor of BC (annual mean: 51.1 %) in the study area, particularly in spring (65.6 %). However, its contributions reached 20.2 % in summer, indicating non-negligible emissions from activities in other regions. In the atmosphere, the SSA BC-induced radiative forcing (RF) over the study region was positive. While at the near surface, the RF exhibited a significant seasonal variation, with the larger RF values occurring in winter and spring. Overall, our findings highlight the importance of controlling BC emissions from SSA to protect the Tibetan Plateau against pollution-related glacier and snow cover melting.

Assessment of interactions between elemental carbon and metals in black carbon: Hydroxyl radical generation and glutathione depletion

Elemental carbon (EC) and metals are two important parts of atmospheric black carbon (BC). However, little information is available regarding the interaction between them and its impacts on the reactive oxygen species (ROS) formation and physiological antioxidants depletion. In this study, we chose six most frequently detected metals (Cu(Ⅱ), Fe(Ⅲ), Mn(Ⅱ), Cr(Ⅲ), Pb(Ⅱ) and Zn(Ⅱ)) in BC and examined their interactions with EC in the ROS generation and glutathione (GSH) oxidation. Results showed that only Cu(Ⅱ) and EC synergically promoted the GSH oxidation and hydroxyl radical (•OH) generation. Other five metals had negligible effects on the GSH oxidation regardless of the presence or absence of EC. The synergistic interaction between Cu(Ⅱ) and EC could be attributed to the superior electrical conductivity of EC. In the process, EC transferred electrons from the adjacent GSH to Cu(Ⅱ) through its graphitic carbon framework to yield Cu(Ⅰ) and GSH radical. Cu(Ⅰ) further reacted with dioxygen to generate •OH, which eventually led to the oxidation of GSH. Our results revealed a new driving force inducing the ROS formation and GSH depletion as well as provided novel insights into the risk assessment of BC.

Exploring the impact of lifestyle and environmental exposures on appetite hormone levels in children and adolescents: An observational study

BackgroundAppetite hormones are considered a promising target in fighting obesity as impaired appetite hormone levels have already been associated with obesity. However, further insights in the drivers of appetite hormone levels are needed. ObjectivesIn this study, we investigated the associations of fasting appetite hormone levels with lifestyle and environmental exposures in children and adolescents. MethodsA total of 534 fasting blood samples were collected from children and adolescents (4-16y,50% boys) and appetite hormone levels (glucagon-like peptide-1 (GLP-1), peptide YY (PYY), pancreatic polypeptide (PP), leptin and ghrelin) were measured. Exposures included dietary quality (fiber-rich food intake, sugar propensity, fat propensity), psychosocial stress (happiness, negative emotions, negative life events and emotional problems), sleep duration, physical activity and environmental quality (long term black carbon (BC), particulate matter <2.5 μM (PM2.5), nitrogen dioxide (NO2) exposure, and green space in a 100 m and 2000 m radius around the residence). A multi-exposure score was calculated to combine all the exposures at study in one measure. Associations of individual exposures and multi-exposure score with appetite hormone levels were evaluated using linear mixed regression models adjusting for sex, age, socioeconomic status, waist-to-height ratio and multiple testing. ResultsGLP-1 was associated with air pollution exposure (NO2 β* = -0.13, BC β* = -0.15, PM2.5 β* = -0.16, all p < 0.001). Leptin was associated with green space in a 100 m radius around the residence (β* = -0.11; p = 0.002). Ghrelin was associated with negative emotions (active ghrelin β* = -0.16; p = 0.04, total ghrelin β* = -0.23; p = 0.0051) and happiness (active ghrelin β* = 0.25; p < 0.001, total ghrelin β* = 0.26; p < 0.001). Furthermore, total ghrelin levels were associated with the multi-exposure score, reflecting unhealthy exposures and lifestyle (β* = -0.22; p = 0.036). DiscussionOur findings provide new insights into the associations of exposures with appetite hormone levels, which are of high interest for preventive obesity research. Further research is crucial to reveal the underlying mechanisms of the observed associations.

Impact of Biomass Burning on Arctic Aerosol Composition.

Emissions from biomass burning (BB) occurring at midlatitudes can reach the Arctic, where they influence the remote aerosol population. By using measurements of levoglucosan and black carbon, we identify seven BB events reaching Svalbard in 2020. We find that most of the BB events are significantly different to the rest of the year (nonevents) for most of the chemical and physical properties. Aerosol mass and number concentrations are enhanced by up to 1 order of magnitude during the BB events. During BB events, the submicrometer aerosol bulk composition changes from an organic- and sulfate-dominated regime to a clearly organic-dominated regime. This results in a significantly lower hygroscopicity parameter κ for BB aerosol (0.4 ± 0.2) compared to nonevents (0.5 ± 0.2), calculated from the nonrefractory aerosol composition. The organic fraction in the BB aerosol showed no significant difference for the O:C ratios (0.9 ± 0.3) compared to the year (0.9 ± 0.6). Accumulation mode particles were present during all BB events, while in the summer an additional Aitken mode was observed, indicating a mixture of the advected air mass with locally produced particles. BB tracers (vanillic, homovanillic, and hydroxybenzoic acid, nitrophenol, methylnitrophenol, and nitrocatechol) were significantly higher when air mass back trajectories passed over active fire regions in Eastern Europe, indicating agricultural and wildfires as sources. Our results suggest that the impact of BB on the Arctic aerosol depends on the season in which they occur, and agricultural and wildfires from Eastern Europe have the potential to disturb the background conditions the most.

Measuring Biogenic Volatile Organic Compounds from Leaves Exposed to Submicron Black Carbon Using Portable Sensor

Biogenic volatile organic compounds (BVOCs) are responsible for the formation of ozone and secondary organic aerosols (SOAs). Our knowledge about how black carbon particles influence BVOC emissions from terrestrial ecosystems is limited; terrestrial vegetation captures black carbon particles as a sink. In this research, the BVOC emissions from the leaves of four terrestrial plants were measured using an RAE PGM-7300 BVOC analyzer. Then, the leaves from four types of trees were exposed to submicron carbon black for 24 h and 48 h in an ambient environment, respectively. Comparisons between the BVOC emissions before and after exposure to submicron carbon black were performed. Our results indicated that the emissions of BVOC from the leaves of four types of trees varied from 90 to 270 μg g−1 h−1 and depended on the species. The exposure to submicron black carbon particles had negligible impacts on the BVOC emissions from the leaves of four types of trees.

Quantifying the dynamical and radiative processes of the drastically weak South Asian summer monsoon circulation in 2015

The South Asian summer monsoon (SASM) circulation in 2015 is the weakest since 2000s, which results in severe drought over broad regions of the Indian peninsula. The 2015 SASM is closely related to the weakened summer meridional thermal contrast between southern Eurasia (SE) and the tropical Indian Ocean (TIO) at the mid–upper troposphere. Based on an updated climate feedback-response analysis method, this study conducts a quantitative attribution analysis of the thermal contrast anomalies associated with the 2015 SASM to multiple dynamical and radiative processes, particular for aerosol process. Result shows that the 2015 weak SASM is mainly attributed to the effect of water vapor (58%), followed by the effects of atmospheric dynamics (18%), clouds (15%), and aerosols (15%), respectively. These positive effects are partially offset by the negative contribution from surface dynamic process (-14%). As the most pronounced factor, the water vapor process weakens the SASM circulation via inducing SE cooling and TIO warming, which is closely linked to the decreased (increased) specific humidity over SE (TIO). Further analysis indicates that the total effect of aerosols is dominated by the changes in black carbon and sea salt. As two important components, the SE cooling and TIO warming separately account for about 51% and 49% to the 2015 SASM. The former is mainly attributed to the cooling effect of clouds, while the latter is mainly induced by the warming effect of atmospheric dynamics. Our result provides a new insight into the 2015 weak SASM from a quantitative perspective.

Causal relationship between air pollution and chronic obstructive pulmonary disease in European and East Asian populations: a Mendelian randomization study

ABSTRACT Epidemiologic studies have suggested a possible association between air pollution and chronic obstructive pulmonary disease (COPD), but it is controversial and difficult to draw causal inferences. Five methods were adopted to evaluate the causal relationship between air pollution and COPD in European and East Asian populations by using MR Analysis. A statistically significant causal relationship between PM2.5 and COPD was observed in the European population (OR: 2.34; 95% CI: 1.06–5.05; p = 0.033). Statistical significance remained after adjustment for confounding factors (adjusted OR: 2.28; 95% CI: 1.01–5.20; p = 0.048). In East Asian populations, PM2.5 absorbance, a proxy for black carbon, was statistically associated with COPD (OR: 1.41; 95% CI: 1.09–1.81; p = 0.007). We did not adjust for confounders in East Asian populations, as the association was independent of known confounders (e.g. smoking, respiratory tract infections, etc.). In conclusion, increased concentrations of PM2.5 and PM2.5 absorbance were associated with an increased risk of COPD.

Chemical properties and single-particle mixing state of soot aerosol in Houston during the TRACER campaign

Abstract. A high-resolution soot particle aerosol mass spectrometer (SP-AMS) was used to selectively measure refractory black carbon (rBC) and its associated coating material using both the ensemble size-resolved mass spectral mode and the event trigger single particle (ETSP) mode in Houston, Texas, in summer 2022. This study was conducted as part of the Department of Energy Atmospheric Radiation Measurement (ARM) program's TRacking Aerosol Convection interactions ExpeRiment (TRACER) field campaign. The study revealed an average (±1σ) rBC concentration of 103 ± 176 ng m−3. Additionally, the coatings on the BC particles were primarily composed of organics (59 %; 219 ± 260 ng m−3) and sulfate (26 %; 94 ± 55 ng m−3). Positive matrix factorization (PMF) analysis of the ensemble mass spectra of BC-containing particles resolved four distinct types of soot aerosol, including an oxidized organic aerosol (OOABC,PMF) factor associated with processed primary organic aerosol, an inorganic sulfate factor (SO4,BC,PMF), an oxidized rBC factor (O-BCPMF), and a mixed mineral dust–biomass burning aerosol factor with significant contribution from potassium (K-BBBC,PMF). Additionally, K-means clustering analysis of the single-particle mass spectra identified eight different clusters, including soot particles enriched in hydrocarbon-like organic aerosol (HOABC,ETSP), sulfate (SO4,BC,ETSP), two types of rBC, OOA (OOABC,ETSP), chloride (ClBC,ETSP), and nitrate (NO3,BC,ETSP). The single-particle measurements demonstrate substantial variation in BC coating thickness with coating-to-rBC mass ratios ranging from 0.1 to 100. The mixing state index (χ), which denotes the degree of homogeneity of the soot aerosol, varied from 4 % to 94 % with a median of 40 %, indicating that the aerosol population lies in between internal and external mixing but has large temporal and source type variability. In addition, a significant fraction of BC-containing particles, a majority enriched with oxidized organics and sulfate, exhibit sufficiently high κ values and diameters conducive to activation as cloud nuclei under atmospherically relevant supersaturation conditions. This finding bears significance in comprehending the aging processes of rBC-containing particles and their activation into cloud droplets. Our analysis highlights the complex nature of soot aerosol and underscores the need to comprehend its variability across different environments for accurate assessment of climate change.

Aircraft observations of aerosol and BC during the East Asian dust storm event: Vertical profiles, size distribution and mixing state

The vertical structure of meteorological elements, black carbon (BC), and aerosols were in situ characterized by the King Air 350 aircraft measurements over the northeast of China during an East Asian dust storm event from April 10 to 13, 2023. The main causes of this dust storm event were the strong winds generated by the Mongolian cyclone, the cold front on the ground provided dynamic conditions, and the unstable atmospheric state provided thermal conditions and less precipitation in the dust source areas led to exposed the ground surface. The number concentrations of BC and aerosol had significant vertical distribution. The number concentration of aerosol in the dust storm (DS) layer increased rapidly with height, while the number and mass concentrations of BC were higher and varied slightly with height. The BC core mass median diameters (MMD) first increased with height, reaching a maximum value of 0.24 μm at 3000 m; and it rapidly decreased to 0.18 μm at 3200 m and then varied slightly with height above 3200 m. BC's bulk relative coating thickness (coated diameter divided by uncoated core diameter Dp/Dc) first decreased with height, reaching a minimum value of 1.16 at 3000 m, then increased with height, reaching a maximum of 1.38 (4250 m). A wind shear layer (7.9 m s−1 at 1850 m) with a sudden drop in temperature (the cooling rate can reach 7.4 °C·(100 m)−1) at 1900 m hinders the transportation of dust particles to the ground, allowing the dust particles to be transported at long-term distances. There were two stratifications in the dust storm layer: DS1 (1700–3000 m, the vertical wind speed was downward, the horizontal wind speed was small) and DS2 (3000–4500 m, the vertical wind speed was upward, the horizontal wind speed was large). The distinct atmospheric flow field conditions between DS1 and DS2 led to different BC and aerosol pollution characteristics. In DS2, the number concentrations of BC and aerosol were higher, the aging ratio of BC particles was higher, and the size of the core particle of BC was smaller. The concentrations of BC, aerosol, Dp/Dc, and MMD in DS2 were 1.1, 59.0, 1.02, and 0.84 times higher than those in DS1, respectively. Dust particles transported over long distances were primarily small. The number concentrations of aerosols at 0.1–0.12 μm and 0.1–0.24 μm were higher in DS1 and DS2, respectively. Still, the number concentration of aerosol at 0.12–0.28 μm in DS1 was lower than in the planetary boundary layer (PBL) and residual layer (RL).

Particle emissions from heated tobacco products.

This study determines the particle emissions from five heated tobacco products (HTPs). An aethalometer is used for the determination of black carbon (BC) and an aerosol monitor for total particulate matter (PM) concentration and also PM fractions (1, 2.5, 4, and 10 μm) in the mainstream emissions of 5 HTPs: IQOS, LIL, PULZE, ILUMA, and GLO. Fifteen different flavors were used, five sticks per flavor, which were smoked using a peristaltic pump under both ISO and Canadian smoking regimes. The method repeatability was determined using 15 sticks of one flavor for each brand for each smoking regime. All HTPs emit particles, and more than 99.7% of the particles emitted are smaller than 1 μm. Both BC and PM emissions show quite low repeatability. Particle emissions increase in relation to the heating temperature and the intensity smoking regime, and are depending on the flavor used. BC corresponds to a small percentage of total PM. Although HTPs are promoted as products of reduced risk compared to conventional cigarettes, high particle concentrations are detected in their emissions, depending on the smoking regime, the flavor used, and the operation parameters. PM emissions vary significantly between different brands under the ISO smoking regime, probably due to the heating temperature. In contrast, PM emissions under the Canadian smoking regime do not vary significantly between different brands. This could probably be attributed to the fact that increased puff frequency does not allow the device to cool down between puffs, resulting in an increase in PM emissions for all the brands, but not dependent on the maximum heating temperature of the device. BC emissions only consist of a very small fraction of PM and do not vary significantly between different brands under both smoking regimes.

Hyper-local source strength retrieval and apportionment of black carbon in an urban area

Neighborhood-scale air pollution hotspots have recently been identified through detailed field campaigns, including the 100x100 Black Carbon Experiment which took place in West Oakland, CA, in 2017. Here, high-resolution nested atmospheric simulations are used together with a Bayesian inversion framework to estimate source apportionment at the hyper-local scale for a neighborhood in West Oakland. Forward simulations are performed with the Weather Research and Forecasting (WRF) model using 6 grid nests from 11.25 km to 2 m horizontal resolution. On the finest grid, building geometries are resolved using the immersed boundary method. Seven point sources and four line sources at known locations are included in the forward simulation for two 1-h periods during the 2017 field campaign. Data from 12 black carbon sensors are used to perform source inversion using a Markov Chain Monte Carlo approach, which provides a probability distribution for each of the 11 source strengths. From this, a most-likely plume can be created using the peaks of the distributions, and source apportionment can be estimated for each sensor. In addition, a composite plume can be constructed to indicate 90% confidence that concentrations are above or below a specified value. With this probabilistic analysis, it is possible to determine that more than half of the neighborhood has black carbon concentrations of higher than 0.4 μg/m3, with some areas higher than 3 μg/m3 during the time periods studied.

Characterizing sedimentary black carbon in the Pearl River Estuary, Southern China

Sedimentary black carbon in coastal regions plays an important role in global carbon cycles due to its refractory nature in sediments. In this study, we conducted the first comprehensive investigation on black carbon (BC) in surface sediments of the Pearl River Estuary (PRE), a large tropical estuary system in China. We used two different analytical methods: IMPROVE-A thermal optical reflectance (TOR) and chemothermal oxidation (CTO-375) to constrain the distribution, and TOR can further constrain the composition (i.e., char and soot). The BC concentration determined by the TOR method (BCTOR) ranged from 0.07 to 7.13 mg/g, with char and soot contents ranging from 0.04 to 6.98 mg/g and 0.03–0.43 mg/g, respectively. The BC concentrations measured by the CTO-375 method (BCCTO) ranged from 0.27 to 1.88 mg/g. Char was the predominant constituent (87%) of sedimentary BCTOR in the PRE. Both char and soot had higher concentrations locating near the outlets and on the Shenzhen coast, indicating that they were sourced through direct fluvial transport and surface runoff. Soot particles were transported farther from fluvial sources than char particles. We estimated that the burial flux of BCTOR in the PRE sediments was 2.97 ± 1.61 mg/cm2/yr, acting as an important sink of BC. This study implies that large river estuaries are hotspots for BC burial, sinking a large amount of organic carbon from terrestrial reservoirs.

IJCM_333A: Household Air Pollution Exposure and Autism Spectrum Disorder Outcomes in Children: Insights from the HAPIN India Study

Background: The global public health challenge of household air pollution, stemming from conventional cooking practices and the widespread use of solid fuels, is a critical concern. Exposure to indoor air pollutants has been associated with adverse health outcomes, particularly affecting vulnerable populations like pregnant women and young children. The Household Air Pollution and Neurodevelopment (HAPIN) study addresses this issue through a multicentric randomized controlled trial spanning four diverse countries: Guatemala, India, Peru, and Rwanda. Objectives: The study aims to evaluate the prevalence of autistic spectrum disorder among children residing in HAPIN study site of India. Methodology: A cross-sectional assessment for autism spectrum disorders within the HAPIN cohort was done.365 children aged 2 to 3 years were studied to explore the potential link between household air pollution and autism spectrum disorder (ASD). Household air quality, measuring PM2.5, CO, and black carbon, was assessed using established protocols. Neurodevelopmental outcomes, particularly ASD, was screened using the Modified Checklist for Autism in Toddlers (M-CHAT) in children aged 2 to 3 years, and screened positive children were evaluated by a psychiatrist to diagnose autism spectrum disorder using DSM-5 criteria. Results: There is significant association between exposure to air pollutants (PM2.5, CO, and black carbon) and the diagnosis of autism spectrum disorder (ASD), with a prevalence rate of 5.48%. Conclusion: ASD prevalence rate of 5.48%, underscore the global relevance of the impact of household air pollution on neurodevelopment. Urgent interventions are warranted to mitigate the risk of ASD, particularly for vulnerable populations like pregnant women and young children, emphasizing the imperative for cleaner cooking practices and improved indoor air quality.

The Associations of Prenatal Exposure to Fine Particulate Matter and Its Chemical Components with Allergic Rhinitis in Children and the Modification Effect of Polyunsaturated Fatty Acids: A Birth Cohort Study.

Polyunsaturated fatty acids (PUFAs) have been shown to protect against fine particulate matter in aerodynamic diameter ()-induced hazards. However, limited evidence is available for respiratory health, particularly in pregnant women and their offspring. We aimed to investigate the association of prenatal exposure to and its chemical components with allergic rhinitis (AR) in children and explore effect modification by maternal erythrocyte PUFAs. This prospective birth cohort study involved 657 mother-child pairs from Guangzhou, China. Prenatal exposure to residential mass and its components [black carbon (BC), organic matter (OM), sulfate (), nitrate (), and ammonium ()] were estimated by an established spatiotemporal model. Maternal erythrocyte PUFAs during pregnancy were measured using gas chromatography. The diagnosis of AR and report of AR symptoms in children were assessed up to 2 years of age. We used Cox regression with the quantile-based g-computation approach to assess the individual and joint effects of components and examine the modification effects of maternal PUFA levels. Approximately and 8.07% of children had AR and related symptoms, respectively. The average concentration of prenatal was . was positively associated with the risk of developing AR [hazard ratio ; 95% confidence interval (CI): 1.16, 2.96 per ] and its symptoms (; 95% CI: 1.22, 2.62 per ) after adjustment for confounders. Similar associations were observed between individual components and AR outcomes. Each quintile change in a mixture of components was associated with an adjusted HR of 3.73 (95% CI: 1.80, 7.73) and 2.69 (95% CI: 1.55, 4.67) for AR and AR symptoms, with BC accounting for the largest contribution. Higher levels of n-3 docosapentaenoic acid and lower levels of n-6 linoleic acid showed alleviating effects on AR symptoms risk associated with exposure to and its components. Prenatal exposure to and its chemical components, particularly BC, was associated with AR/symptoms in early childhood. We highlight that PUFA biomarkers could modify the adverse effects of on respiratory allergy. https://doi.org/10.1289/EHP13524.

Black carbon emissions and its impact on the monsoon rainfall patterns over the Indian subcontinent: Insights into localized warming effects

This study investigates the impact of black carbon (BC) emissions on monsoon rainfall patterns across the Indian subcontinent. The results show that BC exerts localized warming effects, providing valuable insights into the mechanisms influencing the rainfall distribution across the Indian landmass. The study analyzes the vertical profile of mean tropospheric temperature differences between two sets of simulations: (i) with default BC emissions (WBC) and (ii) with BC emissions reduced by 99% (WoBC), conducted for JJAS, 2017, focusing on the region along the eastern coast. The analysis of the tropospheric temperature variations over the eastern coast reveals significant rainfall differences, primarily attributed to the intensification of convective rainfall. The results indicate that WoBC simulation leads to abnormal cooling in the lower troposphere and warming in the mid-upper troposphere, plausibly linked to the release of latent heat from the enhanced convective activity observed over the region. These alterations in the tropospheric temperature profile correspond remarkably well with the changes in the spatial distribution of rainfall over this area, providing valuable insights into the intricate dynamics of the climate system over this region.

Black carbon and PM0.49 characterization in manila north harbour port, Metro Manila, Philippines

Globalization and industrialization have increased the shipping activities in Metro Manila. This increase in economic activity has contributed to the exacerbation of atmospheric particle pollution, particularly black carbon (BC) and particulate matter (PM). In this study, PM0.49 and BC were characterized in North Harbour in Metro Manila, Philippines. Using a multiple-split high-volume cascade impactor, PM0.49 and PM2.5 were collected from December 2019 to January 2020. Equivalent BC (eBC) mass concentrations were measured using an aethalometer (AE33, Magee Scientific) while chemical analysis was also performed using ion chromatography. The PM0.49 was tested for its morphological and mineralogical characteristics. Daily analysis showed no significant difference between the weekday and weekend pollution concentration in the port, although mean concentration (70 ± 21 μg/m3) exceeds that of the 24-hr Philippine air quality guideline value of 50 μg/m3 for PM2.5 concentrations. The particle compositions of PM0.49 are mostly from Si-rich particles and Pb-rich particles. High variability was observed for Mg, Si, Ca, Fe, Cd, Zn, Mn, S, Cl, V, and Cr heavy metals. The carbonaceous species with the highest concentration was organic carbon (OC) (33 ± 9 μg/m3) followed by BC (16 ± 3 μg/m3) and eBC (12 ± 3 μg/m3). An analysis of the ionic species showed SOX and NOX emissions as the primary ions, which are mostly related to ship emissions while the mineralogical analysis showed that soot particles are the main composition of the particles. Overall, the pollution assessment showed that North Harbour is polluted with heavy metals but within the Philippine air quality pollutant standard. In brief, the results of this study suggest that atmospheric pollution in the study site was mostly caused by local anthropogenic sources, particularly vessel emissions. The researchers suggest that a longer study period be conducted to further assess the seasonal variation of atmospheric particle pollution in North Harbour, Metro Manila.

Source apportionment of black carbon using an advanced Aethalometer model in a typical industrial city of China

Black carbon (BC) aerosol can lead to adverse health effects and drive climate change; therefore, the characteristic research and identification of BC sources are essential for lowering emissions. In this study, equivalent black carbon (eBC) measurement was performed using a seven-wavelength Aethalometer (AE33) at an urban site in a typical industrial city (Zibo) of Northern China for the first time. The monitoring was performed from February 2021 to January 2022. The mass absorption cross-section (MAC) of AE33 was optimised using the online elemental carbon (EC) data, and eBC was corrected using the MAC. The corrected annual BC concentration was 1.72 ± 1.18 µg/m3. The diurnal variation of BC depicted a bimodal distribution. Furthermore, the BC concentration on weekends was 18 % lower than on weekdays. The diurnal variation and weekend effect reflect the critical contributions of traffic emission to BC concentration. The source apportionment of BC was calculated by a constraining Aethalometer model, which restricted the Ångström exponent using the online potassium ions. The results revealed that BC was not significantly affected by biomass burning (BCbb) in Zibo. The relative contribution of BCbb was higher in winter than in other seasons. The daily morning peak of BC was primarily influenced by traffic sources, whereas the contribution of biomass burning increased after 17:00 in the evening peak. Our findings suggest that it is more important to control fossil fuel sources for BC emission reduction in Zibo, while it is necessary to strengthen the control of biomass combustion sources in winter.

Exploring the factors responsible for aerosol asymmetric trends over Indo-Gangetic Plain using remote sensing observations

The present study investigates the influencing factors responsible for the asymmetry in aerosol optical depth (AOD) trends using long-term datasets (2003–2019) over western and eastern Indo-Gangetic Plain (IGP) regions during the pre-monsoon season. Analysis from Modern-Era Retrospective Analysis for Research and Applications Version-2 (MERRA-2) for different aerosols illustrates that dust aerosols dominate over the western IGP (W-IGP), while sulphate and carbonaceous aerosols (black carbon (BC) and organic carbon (OC)) majorly contributed to the total AOD over the eastern IGP (E-IGP). Our study reveals a significant decline in AOD over the W-IGP, while a rising trend over E-IGP from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations. A dipole pattern in AOD trends over IGP indicates the aerosol loading from combined effects of various natural and anthropogenic emissions under favourable meteorological conditions over the W-IGP and E-IGP, respectively. Furthermore, the declining AOD trend over W-IGP is mainly attributed to increased pre-monsoonal rainfall, which supports the wet deposition, increases soil moisture, thus reducing soil erodibility, and correlates strongly with meteorological factors. The rising AOD trend over the E-IGP appears to be influenced by increased anthropogenic emissions (i.e., BC, OC, and sulphate) from the industrialization of the region, decreased rainfall, and enhanced westerly-induced advection of aerosols from W-IGP. Our study indicates that the regional meteorological variables and anthropogenic sources influence changes in the AOD trends over the IGP region.