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Urban air pollution can vary sharply in space and time. However, few monitoring strategies can concurrently resolve spatial and temporal variation at fine scales. Here, we present a new measurement-driven spatiotemporal modeling approach that transcends the individual limitations of two complementary sampling paradigms: mobile monitoring and fixed-site sensor networks. We develop, validate, and apply this model to predict black carbon (BC) using data from an intensive, 100-day field study in West Oakland, CA. Our spatiotemporal model exploits coherent spatial patterns derived from a multipollutant mobile monitoring campaign to fill spatial gaps in time-complete BC data from a low-cost sensor network. Our model performs well in reconstructing patterns at fine spatial and temporal resolution (30 m, 15 min), demonstrating strong out-of-sample correlations for both mobile (Pearson's R ∼ 0.77) and fixed-site measurements (R ∼ 0.95) while revealing features that are not effectively captured by a single monitoring approach in isolation. The model reveals sharp concentration gradients near major emission sources while capturing their temporal variability, offering valuable insights into pollution sources and dynamics.

Black carbon aerosols and PM2.5 have been identified as one of the major factors responsible for the ambient air quality index in Jamshedpur. The real-time measurement of BC concentration is determined with the help of an Aethalometer (AE-33), which was analyzed from November 2022 to April 2023. In the present study, we have compared the aerosol parameters during haze (Nov-Jan) and normal days (Oct, Feb-May) periods. We estimated the average mass concentration of BC, PM2.5 and AQI during haze days (HD) and normal days (ND), respectively. BC concentrations showed significant temporal variations with around 6.25 ± 3.05 and 2.52 ± 2.75 μg m − 3 during HD and ND, respectively. While PM2.5 and AQI concentrations in HD were found to be 264.64 ± 58.8 and 267.84 ± 56.72 μg m − 3, which were double of 130.19 ± 60.1 and 141.98 ± 52.44 μg m − 3, respectively, during ND. The highest monthly concentration of BC, PM2.5 and AQI was noticed in December at 8.35, 291.9 and 298 μg m − 3, respectively. Large-scale energy production in industries can consume coal and petroleum as primary fuels, which may be a major reason for the high concentrations. Due to low mixing height during winter, these emissions are not spread properly. Hence, higher concentration was found in December. The values for BC/PM2.5 were observed as 2.37% with a range from 0.54 to 4.4% and 2.48% (0.5 to 21.78%) during HD and ND, respectively. The study determined the source apportionment of BC with biomass dominance found in HD. The % BB was obtained around 53.1% throughout haze session, which was approximately 1.57 times higher than normal day (33.77%). In winter, burning wood and other solid fuels to warm the atmosphere may increase the contribution of BB to BC emissions. Furthermore, the backward trajectories calculated that air masses were concentrated within the IGP regions at lower altitudes during the HD while there was a diverse circulation of air parcels throughout the ND. Air masses were majorly coming to the receptor site from west India in ND. GIOVANNI NASA satellite model proved that surface mass concentrations of BC and PM2.5 were observed higher over IGP areas as well as other parts of India during HD with respect to ND. [ABSTRACT FROM AUTHOR]

Coastal estuaries and adjacent continental shelf seas constitute vital global carbon reservoirs, and the sources and transformations of organic carbon in these regions are crucial to global biogeochemical cycles and climate change. This study investigated the total organic carbon (TOC), total nitrogen (TN), black carbon (BC), and their stable carbon and nitrogen isotopes (δ15NTN, δ13CTOC, δ13CBC) in the surface sediments of the Pearl River Estuary (PRE) and its adjacent northern South China Sea (NSCS) aiming to assess the impact of human activities on organic carbon dynamics in these areas. Results showed that the highest TOC concentrations occurred in the inner PRE due to intense human activities, and decreased seaward. The west side of the PRE exhibited higher TOC levels than the east side, which was attributed to differences in hydrodynamic processes and human activities. The westward flow of the Pearl River diluted water, which carried terrestrial organic matter inputs due to the influence of the Coriolis effect and intense local human activities, was a primary contributor to higher TOC levels on the west side (terrestrial source). In contrast, increased productivity and intensive mariculture activities on the east side predominated as sources of organic matter (marine source). Similar to the TOC, BC and TN sources were mainly influenced by human activities. δ15NTN distribution shows that TN in the east side of PRE mainly originated from industrial wastewater input from the Pearl River, while in the east side TN was mainly from domestic sewage discharge. Additionally, BC sources have shifted from primarily biomass combustion in the 1990s to fossil fuel emissions presently. Isotopic analysis revealed that over 70% of BC originated from fossil fuel inputs and C3 plant combustion, highlighting the significant influence of human activities in the PRE and adjacent NSCS, and underscoring the need for effective management and protection of the eco-environment in these regions. [ABSTRACT FROM AUTHOR]

The Brazilian Pantanal region experiences intense biomass burning during the dry season, releasing large quantities of gasses and particles into the atmosphere, which have serious implications on both the climate system and public health. Understanding the dynamics of these emissions is crucial for mitigating the impact on the ecosystem, its functioning, and potential anthropogenic disturbances. This study focused on analyzing emissions in the northern Pantanal during the 2022 drought. Concentrations of fine particulate matter (PM2.5), black carbon (BC), and 25 chemical elements were measured using gravimetry, reflectance analysis, and X-Ray fluorescence, respectively, from samples collected between August and October 2022. The average concentrations of PM2.5 and BC increased approximately 4-fold and 2.5-fold, respectively, compared to averages from a decade ago. Significant increases were also observed in elements such as sulfur (S), potassium (K), iron (Fe), and silicon (Si). The maximum concentrations were comparable to values typical of the southern Amazon, a region known for high deforestation rates and land use changes. Elemental analysis revealed substantial shifts in concentrations, primarily associated with biomass burning (BB) and soil suspension. Additionally, enrichment factor (Ef) analysis showed that lead (Pb) levels, correlated with human activities, were 200 times higher than those found under clean atmospheric conditions. [ABSTRACT FROM AUTHOR]

The Arctic region is experiencing more rapid climate changes than the other parts of the world and serves as a sink for semi‐volatile persistent organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), which can be utilized as molecular markers for pyrogenic carbon, such as black carbon (BC). As the sea ice retreats and increased terrestrial inputs with widespread wildfires, the PAH concentrations in the Arctic Ocean are rising. In this study, the sources and fates of PAHs together with BC in surface sediments from the East Siberian Arctic Shelf (ESAS) were analyzed. Positive matrix factorization (PMF) elucidated a mixed petrogenic and pyrogenic sources and distinct PAH fates associated with diverse input pathways including coastal permafrost erosion contribution (∼30%), petrogenic‐related emission (∼34%), fossil fuel combustion (∼26%), and biomass burning (∼10%). Correlation analysis indicated that BC plays a key role in affecting the behavior and fates of PAHs. In the Chukchi Sea, PAHs are closely associated with soot‐BC, whereas in the Laptev Sea (LS) and west East Siberian Sea (W‐ESS), they exhibit a coupling process with char‐BC. The presence of these carbonaceous materials in the sediments of CS is likely influenced by atmospheric deposition and biological activity, whereas the LS and W‐ESS regions are mainly affected by long‐distance river transport and direct deposition from coastal permafrost. As global warming continues, permafrost thawing induces the remobilization and retranslocation of PAHs, thereby becoming a significant PAH contributor and input pathway in the rapidly changing Arctic coastal margin. Plain Language Summary: The Arctic region is experiencing rapid climate changes, such as reducing sea ice, thawing permafrost, and increasing wildfires. These changes are raising the levels of semi‐volatile pollutants such as polycyclic aromatic hydrocarbons (PAHs) in the Arctic coastal margins, with the potential for the region to become a significant reservoir of sedimentary PAHs. In our study, we examined the large‐scale distribution and fates of PAHs and black carbon (BC) across the East Siberian Arctic Shelf (ESAS), the world's largest shelf system. We discovered that PAHs have mixed sources, including both petrogenic and pyrogenic origins. We also observed differences in how PAHs were transported and sequestrated in coastal versus open sea areas. In the western ESAS, PAHs and BC are mainly influenced by terrestrial inputs such as river discharge and coastal permafrost erosion. In contrast, in the eastern open‐sea regions, they are primarily constrained by atmospheric transport and biological activity are the primary influencing factors. The significant emissions from thawing permafrost along the coasts highlight the growing importance of permafrost‐related erosion as a significant contributor of PAHs in the Arctic Ocean, particularly in the context of future warming. Key Points: Sedimentary polycyclic aromatic hydrocarbons (PAHs) in the East Siberian Arctic Shelf (ESAS) have a mixture of petrogenic and pyrogenic sources with distinct input pathwaysPermafrost erosion serves as a significant input pathway and PAHs contributor in the rapidly changing Arctic coastsBlack carbon plays a key role in the behavior and sequestration of pyrogenic PAHs in the Arctic coastal margins [ABSTRACT FROM AUTHOR]

The effects of global climate change have accelerated the melting of glaciers and the decline of sea ice coverage in the Arctic. In tandem with advancements in icebreaker and other shipping technologies, the navigability of Arctic shipping routes has dramatically improved. Given the geographical advantages of the Arctic region in terms of shipping routes and resource potential, various countries have implemented initiatives to secure a foothold in the Arctic shipping industry. However, the current shipping industry has not yet achieved the ideal state of netzero emissions, and the rapid increase in Arctic shipping has brought serious and even irreversible negative impacts on the Arctic environment. The study employs document and policy analyses to conduct an in-depth examination of legal and policy documents related to Arctic shipping, especially those from the past 5 years, systematically outlining the relevant legal and policy frameworks, as well as their historical context. At the same time, interdisciplinary research methods are utilized to comprehensively assess the new challenges. It is concluded that against the backdrop of the Arctic region's unique and fragile environment, the International Maritime Organization (IMO) and the Arctic Council are introducing increasingly stringent regulations for Arctic shipping, posing a complex array of challenges for the industry. Not only must it navigate the mounting pressure of emission reduction policies and intensifying public scrutiny but it must also overcome a multitude of complex technical and operational hurdles. Consequently, the joint efforts of the international community are essential to promote the sustainable development and emission reduction goals of the Arctic shipping industry. [ABSTRACT FROM AUTHOR]

In megacities, road traffic is a major source of particulate matter (PM), requiring a critical understanding of effective air pollution control. Despite existing methods to determine PM emission factors (EFs) of vehicles, accurate estimation of PM emissions under real driving conditions remains challenging. We aimed to assess the EFs of organic aerosol (OA) and equivalent black carbon (eBC) from vehicles through on-road measurements in Seoul, Korea, to understand real-world PM emissions. We used a mobile laboratory equipped with an aerosol mass spectrometer and an aethalometer to measure the composition of PM. On-road measurements were conducted in vehicle tunnels, urban roadways, and residential areas, and the characteristics of measurement points were compared and analyzed. Our results showed that concentrations of OA increased proportionally with the influence of vehicle exhaust, while oxidation states of the OA decreased. Mobile measurements revealed spatial heterogeneities in aerosols, highlighting distinct characteristics of fresh OA on vehicle roads and elevated oxidation state values in residential areas. Active nitrate formation near vehicles led to elevated NO3 concentrations on roads compared to residential areas. Our study shows that mobile PM measurements, including OA and eBC, are valuable for the direct evaluation of emission inventories. However, given that the calculated EFs may not be applicable to other cities due to differences in vehicle composition and traffic conditions, the development of city-specific EFs will be necessary in the future. Furthermore, it is recommended to integrate this methodology with conventional emission inventories to identify vehicle-type-specific emissions. [ABSTRACT FROM AUTHOR]

Because of the fractal aggregated structure of black carbon (BC), black carbon refractive index measurements are difficult. There are substantial differences among the over 40 existing measurement schemes and no two schemes are the same. Three typical BC refractive index schemes are chosen to explore the difference in black carbon optical properties and the consequences of the radiative effect. Two schemes are widely used in climate models, and the third is from a newer measurement in 2016. It is shown that black carbon optical properties are sensitive to different refractive indices. The relative differences in extinction coefficient and single scattering albedo can be over 100%. In addition, by using Maxwell–Garnett and Bruggeman mixing rules, it has been found that the effect of internal mixing on aerosol optical properties depends strongly on the choice of refractive index. Using a one‐dimensional radiative transfer model under clear‐sky conditions, we demonstrate that the choice of black carbon refractive index influences the inferred radiative effect. Using the more recent (2016) scheme for pure black carbon can increase the top‐of‐atmosphere radiative effect by 20% relative to the currently widely used lowest‐absorbing scheme. For internally mixed aerosol, the sign of the radiative effect can change depending on which refractive index is used. [ABSTRACT FROM AUTHOR]

Black carbon (BC) is a highly persistent yet poorly understood component of forest soil carbon reservoirs, while its inventory, distribution, and determining factors in forest soils on a large geographic scale remain unclear. Here, we characterized soil BC across 68 Chinese forest sites using benzene polycarboxylic acid method and developed machine learning (ML) models to predict and interpret potential impacts of soil organic matter (SOM) properties, soil physiochemical properties, meteorological conditions, wildfire history, and microbial diversity on BC. Results revealed that SOM properties were the most critical in predicting BC, complemented by the negative impact of mean annual temperature and alkaline mineral composition. The superior prediction accuracy for BC with higher condensed aromaticity (more benzene hexa‐ and penta‐carboxylic acid monomers) likely results from its simpler sources and greater resistance to transformation. This study introduces an effective ML model for predicting and interpreting soil BC inventory to better understand BC cycling. Plain Language Summary: The black carbon (BC) derived from incomplete biomass combustion serves as a potential reservoir to store carbon in land ecosystems. Despite BC's significance in carbon sequestration, its inventory and distribution on a large geographic scale remains elusive. As such, we characterized both the quantity and quality of soil BC for forest sites across China. We find that soil BC content averaged 1.99 ± 1.94 mg C g−1 and constituted 8.8% ± 4.9% of soil organic carbon, without showing a clear geographic distribution pattern. Besides the well‐acknowledged predictive power of machine learning (ML) methodologies, they were introduced to determine the impacts of soil properties and environmental parameters in controlling the BC distribution. We discovered that soil organic matter properties were the most important parameters in predicting BC content, accounting for over 50% of the contribution in model construction based on mean absolute Shapley value. Alongside meteorological conditions, they were further extracted as the key parameters for predicting BC content to simplify the ML model. As a promising complement to traditional geochemical approaches, this research highlights the potential of leveraging ML to predict and interpret BC inventory on a global scale. Key Points: The black carbon (BC) inventory and distribution in Chinese forest soils on a large geographic scale were first determinedMachine learning (ML) models exhibited superior prediction accuracy for BC with higher condensed aromaticitySoil organic matter properties were the most critical in predicting BC content [ABSTRACT FROM AUTHOR]

Black carbon is a short-lived climate warming agent and serves as a crucial factor influencing the climate. Numerous models, observations, and laboratory studies have been conducted to quantify black carbon's direct or indirect impacts on the climate. Here, we applied bibliometric analysis to identify research trends and key topics on black carbon in the climate field. Based on the Web of Science (WOS) Core Collection database, a total of 4903 documents spanning the period from 2000 to 2023 were retrieved and screened, focusing on the topic of black carbon in the climate field, resulting in the Black-Carbon Climate Local (BCL) dataset. Our study examines the influence and trends of major countries, institutions, and authors in this field. The results show that China and the United States hold leading positions in terms of the number of publications. Based on keyword networks, the BCL dataset is segmented into six distinct research directions, and representative keywords of each direction include biomass burning, radiative forcing, air pollution, aerosol optical depth, optical properties, and biochar. This study helps to identify the current research status and trends of black carbon in the climate, highlighting main research directions and emerging topics. [ABSTRACT FROM AUTHOR]

The linear depolarization ratio (LDR) of backscattering is a key parameter for distinguishing particle types. The measured LDRs of smoke in previous studies are highly variable and different from each other. Existing research on smoke aerosols considers only the internal mixing state of the black carbon (BC) particle population either by ignoring the externally mixed organic carbon (OC) particle population or by evaluating the LDR of smoke aerosols using the results of individual particles rather than the particle population. The field‐measured LDR of smoke then becomes difficult to interpret properly. The recent prescribed forest burning experiment in China showed that the LDR of freshly emitted smoke varies between 0.0% and 20.1% in wavelength (λ) of 532 nm. Electron microscopy images also showed that coated BC and pure OC exist simultaneously in biomass burning aerosols. Therefore, this study evaluates the influence of various parameters on the LDR of smoke by considering the internal and external mixing states. The calculated LDRs of the smoke aerosols were found to vary between 0.0% and 28.2% when λ is equal to 532 nm. The calculation results indicate that the LDR of smoke is slightly influenced by BC, considerably affected by the externally mixed OC, and is essentially dominated by the latter's morphology and particle size distribution. High levels and rapid changes of LDR of smoke can be well explained by nonsphericity and particle size distribution of externally mixed OC. This study advances the research on the measurement and evaluation of the LDR of smoke aerosols. Plain Language Summary: The backscattering linear depolarization ratio (LDR) is dependent on the particle shape and composition and can be differed among diverse particle types. Previous studies have shown significant variation in measured LDRs of smoke in the literature without considering the external mixing state of the particle population in the LDR calculations. We conducted the prescribed burning experiment in China, and measured the LDR of emitted smoke from biomass burning using lidar on site. Our measurement revealed wide and rapid variations in the LDR of newly emitted smoke. We used numerical simulations to calculate the LDR of the smoke particle population to interpret the measured results and those reported in the literature. Taking into account externally mixed ellipsoidal organic carbon (OC) particles, the smoke LDR is very sensitive to the size distribution and morphology of the externally mixed OC. The results can well explain the LDR of smoke in the field observations. This study generates useful information for the accurate measurement and assessment of the LDR of smoke. Key Points: The impact of externally mixed ellipsoidal OC on the bulk LDR was theoretically studied for the first timeBoth external and internal mixing state of particle population were taken into account in the calculationThe quantifications well explain the observation trends both in the literature and in our recent field measurement [ABSTRACT FROM AUTHOR]

Previous modeling studies have not properly explained the measured mass absorption cross section (MAC) at 550 nm, the linear backscattering depolarization ratio (LDR) at 355 and 532 nm, and the scattering matrix of soot at 532 nm. In this work, we attempt to use a black carbon (BC) model with an intrinsic organic carbon (OC) coating to explain the large MAC, large LDR, and measured scattering matrix. Our results show that the bare fractal BC model is not able to explain MAC, LDR, and scattering matrix simultaneously and that the modeling values do not cover the measurement range. This study shows that the modeled LDR and scattering matrix can cover the measurement range if we constrain the MAC of the BC in the measurement range by the intrinsic OC coating when we consider the effects of monomer radius, monomer number, and monomer overlap simultaneously. Therefore, intrinsic OC coating can be a significant source of uncertainty in the optical properties of fresh soot. Plain Language Summary: Since soot is the most important absorbing particle in the atmosphere, an accurate calculation of the optical properties of soot is of great importance for climate assessment and remote sensing. However, some of the observed optical properties of soot are difficult to explain with current models. In this study, a black carbon (BC) model with an intrinsic organic carbon (OC) coating is used to explain these difficult‐to‐explain optical properties. The results show that the simulated mass absorption cross section (MAC), linear backscattering depolarization ratio (LDR), and scattering matrix are difficult to explain when only the influence of BC is considered, although the effects of monomer size, monomer number, and monomer overlap are taken into account. Range of observation. However, after accounting for the intrinsic OC coating, the model is able to account for the range of realistic optical observations. Therefore, the intrinsic OC coating may be responsible for some optical properties that are difficult to explain with the current models. Key Points: The model of pure black carbon (BC) has difficulty explaining some optical observations of sootWe have proposed a soot model consisting of a BC core and an intrinsic organic carbon (OC) shellThe intrinsic OC coating may be a cause of some unexplained optical properties in current models [ABSTRACT FROM AUTHOR]

The environmental effects of airborne micro‐ and nano‐size plastic particles are poorly understood. Microscopy and chemical analyses of atmospherically deposited particles on snow surfaces at high elevation (2,865–3,690 m) in the Upper Colorado River basin (UCRB; Colorado Rocky Mountains) revealed the presence of black substances intimately associated with microplastic fibers, particles interpreted to have originated as tire matter. Identical and similar particles occur in shredded tires and road‐surface samples. The substance responsible for the black color of all tires is carbon black, a graphitic light‐absorbing tire additive produced by hydrocarbon combustion that homogeneously permeates the mixture of tire polymers and other additives. Such black tire matter may thus exert radiative effects closely similar to those of black carbon. The presence in snow of many organic compound types common to tires, measured by two‐dimensional gas chromatography, suggests that atmospherically deposited black road‐tire‐wear matter is among the light‐absorbing particulates that advance the onset and rate of snow melt in the UCRB. The mass of road‐tire‐wear particles shed from vehicles may be estimated by multiplying measured amounts of eroded tire‐per‐distance traveled by vehicular distances. Under a combination of measurements and assumptions about the amounts and radiative properties of atmospheric tire‐wear particles, the radiative effects of these particles might add about 10%–30% to those effects from black carbon, an estimate ripe for revision. On regional and global scales, the amounts and effects of emitted and deposited tire‐wear matter likely vary by factors of geographic source, transport pathway, and depositional setting. Plain Language Summary: A major source for airborne microplastic particles is road‐tire wear. Microscopy and chemical analyses of wind‐blown particles on dirty, high‐elevation (2,865–3,690 m) snow surfaces in the Colorado Rocky Mountains revealed the presence of black substances intimately mixed with microplastics, particles interpreted as tire matter. Identical and similar particles occur in shredded tires and in samples collected from road surfaces. The black substance responsible for the black color of all tire particles is carbon black that homogeneously permeates the mixture of tire polymers and other additives. The mass of particles produced by road‐tire wear may be estimated by multiplying measured amounts of eroded tire‐per‐distance traveled by vehicular travel distances. Under assumptions of amounts of tire‐wear matter emitted to the atmosphere, their presence as light‐absorbing particles likely contribute to melting of snow and ice as well as to warming the atmosphere. Key Points: Light absorbing particles, as blackened microplastic matter from road‐tire wear, occur in snow of the Colorado Rocky Mountains (2013–2021)The mass of road‐tire‐wear particles annually generated is estimated to be 6,550 kt, of which about 655–1,965 kt might become airborneThe results are relevant to radiation modeling of snow and ice surfaces as well as the atmosphere [ABSTRACT FROM AUTHOR]

Assessments of air quality in industrial cities are receiving much attention, especially in regions sensitive to the ecological and climate changes. The atmospheric aerosol loading was studied in the city of Novy Urengoy during the summer–autumn of 2023. Particle number concentration and the mass concentration of particles with a size less than 10 µm (PM10) and 2.5 µm (PM2.5), as well as black carbon (BC), were measured by the mobile Aerosol Complex. The portion of fossil fuel combustion (FF%) and biomass burning (BB%) was estimated using the aethalometer model. BC concentrations increased during pollution episodes recorded at the end of June (I) and July (II) and, in the beginning of August (III) and September (IV), doubled on average in comparison with the level of urban emissions. During episode IV of maximum pollution, the ВС concentration and its impact on PM2.5 increased 4 and 5 times, respectively. At that time, the portion of fossil fuel combustion FF% approached 96%. Cluster analyses of ВС dependence on the wind speed and direction revealed the sector of high concentration source. FF% indicated the direction of the emissions from the biggest industrial enterprise of the Urengoy oil and gas condensate field. Wildfire plume was identified by ВВ% from the south of Siberia. [ABSTRACT FROM AUTHOR]

Black carbon (BC) is a crucial air pollutant that contributes to short-lived climate forcing and adverse health impacts. BC emissions have rapidly declined over the past three decades and it is important to uncover the major factors behind this decline. Herein, the temporal trends in BC emissions were compiled from 146 detailed sources from 1960 to 2019. Results revealed that the major emission sources were residential solid fuel usage, coke production and brick production. Furthermore, 96.9% of the emission reduction from 3.03 Tg in 1995 to 1.02 Tg in 2019 was attributed to these three sources. It was determined that the transition in residential energy/stove usage, phasing-out of beehive coke ovens and brick kiln upgrading were the most important drivers leading to this reduction and will continue to play a key role in future emission mitigation. In addition, this study identified the need to address emissions from coal used in vegetable greenhouses and the commercial sector, and diesel consumption in on/off-road vehicles. [ABSTRACT FROM AUTHOR]

Black carbon (BC) changes the radiative flux in the atmosphere by absorbing solar radiation, influencing photochemistry in the troposphere. To evaluate the seasonal direct radiative effects (DREs) of BC and its influence on surface atmospheric oxidants in China, the WRF-Chem model was utilized in this study. The simulation results suggested that the average annual mean values of the clear-sky DREs of BC at the top of the atmosphere, in the atmosphere and at the surface over China are +2.61, +6.27 and −3.66 W m−2, respectively. Corresponding to the seasonal variations of BC concentrations, the relative changes of the mean surface photolysis rates (J[O1D], J[NO2] and J[HCHO]) in the four seasons range between −3.47% and −6.18% after turning off the BC absorption, which further leads to relative changes from −4.27% to −6.82%, −2.14% to −4.40% and −0.47% to −2.73% in hydroxyl (OH) radicals, hydroperoxyl (HO2) radicals and ozone (O3), respectively. However, different from the relative changes, the absolute changes in OH and HO2 radicals and O3 after turning off BC absorption show discrepancies among the different seasons. In the North China Plain (NCP) region, O3 concentration decreases by 1.79 ppb in the summer, which is higher than the magnitudes of 0.24–0.88 ppb in the other seasons. In southern China, the concentrations of OH and HO2 radicals reach the maximum decreases in the spring and autumn, followed by those in the summer and winter, which is due to the enhancement of solar radiation and the summer monsoon. Thus, BC inhibits the formation of atmospheric oxidants, which further weakens the atmospheric oxidative capacity. [ABSTRACT FROM AUTHOR]

Black carbon (BC) aerosols have attracted wide attention over the world due to their significant climate effects on local and global scales. BC extinction aerosol optical thickness (AOT), scattering AOT, and single scattering albedo (SSA) over China are systematically studied based on the MERRA-2 satellite reanalysis data from 1983 to 2022 in terms of the spatial, yearly, seasonal, and monthly variations. The extinction and scattering AOTs of BC show similar spatial distribution, with high values in eastern and southern China, generally as opposed to BC SSA. A decrease in BC extinction and scattering AOTs has been documented over the last decade. The mean BC extinction AOT, scattering AOT, and SSA over China are 0.0054, 0.0014, and 0.26, respectively. The BC SSA showed small variations during 1983–2022, although a high BC extinction AOT and scattering AOT have been seen in the last two decades. During different decades, the seasonal patterns of BC extinction and scattering AOTs may differ, whereas the BC SSA shows seasonal consistency. Significant monthly variations in the BC SSA are seen over four decades, which are in agreement with their seasonal patterns. The mean BC extinction AOTs are 0.037, 0.033, 0.023, and 0.0054, whereas the average BC scattering AOTs are 0.0088, 0.0082, 0.0060, and 0.0014 in the Pearl River Delta (PRD), Yangtze River Delta (YRD), Beijing–Tianjin–Hebei (BTH) region, and Tarim Basin (TB), respectively. It is interesting to see that BC SSA values in the TB region are generally higher than those over the PRD, YRD and BTH areas, whereas the reverse is true for BC extinction and scattering AOTs. This study provides references for further research on black carbon aerosols and air pollution in China. [ABSTRACT FROM AUTHOR]

Diesel engine exhaust (DEE) is carcinogenic and potentially hazardous for those working in close proximity to diesel-powered machines. This study characterizes workplace exposure to DEE and its associated particulate matter (PM) during outdoor construction activities. We sampled at 4 construction sites in the Copenhagen metropolitan area. We used portable constant-flow pumps and quartz-fiber filters to quantify personal exposure to elemental carbon (EC), and used real-time instruments to collect activity-based information about particle number and size distribution, as well as black carbon (BC) concentration. Full-shift measurements of EC concentration ranged from < 0.3 to 6.4 µg/m3. Geometric mean (GM) EC exposure was highest for ground workers (3.4 µg/m3 EC; geometric standard deviation, GSD = 1.3), followed by drilling rig operators (2.6 µg/m3 EC; GSD = 1.4). Exposure for non-drilling-rig machine operators (1.2 µg/m3 EC; GSD = 2.9) did not differ significantly from background (0.9 µg/m3 EC; GSD = 1.7). The maximum 15-min moving average concentration of BC was 17 µg/m3, and the highest recorded peak concentration was 44 µg/m3. In numbers, the particle size distributions were dominated by ultrafine particles ascribed to DEE and occasional welding activities at the sites. The average total particle number concentrations (PNCs) measured in near-field and far-field positions across all worksites were 10,600 (GSD = 3.0) and 6,000 (GSD = 2.8)/cm3, respectively. Sites with active drilling rigs saw significantly higher average total PNCs at their near-field stations (13,600, 32,000, and 9,700/cm3; GSD = 2.4, 3.4, and 2.4) than sites without (4,700/cm3; GSD = 1.6). Overall, the DEE exposures at these outdoor construction sites were below current occupational exposure limits for EC (10 µg/m3 in Denmark; 50 µg/m3 in the European Union), but extended durations of exposure to the observed DEE levels may still be a health risk. [ABSTRACT FROM AUTHOR]

Black carbon (BC), primarily originating from fossil fuel and biomass combustion, holds significance for global carbon cycling, climate change, and human health. Despite a lake's role as a carbon sink, detailed information about BC sedimentary burial flux and sink in its sediment remains insufficiently explored. The current study investigates the distribution, sources, and burial flux of BC and its subtypes (char and soot) in the surface sediment of Daye Lake, the largest lake in Huangshi City, central China. BC concentrations in the sediment ranged from 0.10 to 3.60 mg/g, corresponding to 0.40%–17.02% of organic carbon (OC). Higher values of BC and BC/OC observed in the western region suggest direct terrestrial input via river discharge and surface runoff, influenced by anthropogenic activities. In contrast, variations in char/soot ratios reflect diverse combustion sources and hydrological dynamics in different regions. The indications from BC/OC and char/soot ratios imply that fossil fuel combustion is the predominant sources. The weak correlations between BC and OC suggest that they may come from different sources or undergo different processes that affect their distribution in the lake sediment. However, a stronger correlation was observed between BC and soot, as well as between char and soot, indicating potential similarities in their input pathways. The BC burial flux displays notable variations across the lake, ranging from 0.69 to 24.07 g/m2/yr, with elevated values observed in the western region. The BC sink in the sediments of Daye Lake was estimated to be 0.635 Gg/yr. Though locally small, it significantly contributes to the broader picture of BC burial in Chinese lakes and the global distribution of BC in lake ecosystems. [ABSTRACT FROM AUTHOR]

Lakes act as natural reservoirs for storing organic material, and comprehending how organic carbon (OC) and black carbon (BC) are deposited in lake sediments is crucial for understanding the global carbon cycle and its impact on climate and ecosystems. In this study, we examined changes in the deposition patterns of OC and BC in Yinjia Lake (YJL) over the past 110 years, using a 60 cm sediment core dated with 210Pb. Our aim was to discern how these changes relate to human activities and other influencing factors in the region of southeast Hubei, central China. Our findings revealed a consistent rise in total organic carbon (TOC) and total nitrogen (TN) concentrations, indicating a gradual increase from the bottom upwards. Analysis of C/N ratios and δ13C values showed that the OC in the sediment mainly originated from phytoplankton and terrestrial C3 plants. Over the past century, OC burial rates (OCBR) in the YJL core increased from 61.35 to 86.69 g m−2 yr−1, primarily due to increased primary production resulting from intensified local agriculture and urban growth. Temperature was found to influence OCBR, while precipitation had little impact on OCBR dynamics in sedimentary environments. BC burial rates in YJL ranged from 3.67 to 11.51 g m–2 yr–1, significantly exceeding those observed in other lakes worldwide. The fluctuations in BC burial rates correlated with shifts in local industrial practices and energy consumption. In recent years (post-2005), BC burial rates have declined, likely due to reduced pollutant emissions resulting from the implementation of emission-control policies in China. These results provide valuable insights into the interactions between human activities, climate variability, and carbon cycling in lacustrine environments, with implications for regional carbon budgets, ecosystem management, and climate-change mitigation strategies. [ABSTRACT FROM AUTHOR]

Abstract In megacities, road traffic is a major source of particulate matter (PM), requiring a critical understanding of effective air pollution control. Despite existing methods to determine PM emission factors (EFs) of vehicles, accurate estimation of PM emissions under real driving conditions remains challenging. We aimed to assess the EFs of organic aerosol (OA) and equivalent black carbon (eBC) from vehicles through on-road measurements in Seoul, Korea, to understand real-world PM emissions. We used a mobile laboratory equipped with an aerosol mass spectrometer and an aethalometer to measure the composition of PM. On-road measurements were conducted in vehicle tunnels, urban roadways, and residential areas, and the characteristics of measurement points were compared and analyzed. Our results showed that concentrations of OA increased proportionally with the influence of vehicle exhaust, while oxidation states of the OA decreased. Mobile measurements revealed spatial heterogeneities in aerosols, highlighting distinct characteristics of fresh OA on vehicle roads and elevated oxidation state values in residential areas. Active nitrate formation near vehicles led to elevated NO3 concentrations on roads compared to residential areas. Our study shows that mobile PM measurements, including OA and eBC, are valuable for the direct evaluation of emission inventories. However, given that the calculated EFs may not be applicable to other cities due to differences in vehicle composition and traffic conditions, the development of city-specific EFs will be necessary in the future. Furthermore, it is recommended to integrate this methodology with conventional emission inventories to identify vehicle-type-specific emissions. Graphical Abstract

Abstract Indoor air quality can be affected by the presence of atmospheric pollutants, which impact severely in human health. The objectives were to show the characterization of particle number (PN0.3–PN2.5), particles mass (PM1.0, PM2.5, PM10), Black Carbon (BC), Brown Carbon (BrC) and bioaerosols (fungi and bacteria) in indoor environments of three pizzerias that have wood ovens as fuel at Londrina, Brazil. Mean Particle mass concentration varied amongst the pizzerias (28.9–42.4 µg m−3 for PM2.5) with the levels of BC and BrC reaching up to 42.9 µg m−3 and 29.4 µg m−3, respectively. These were correlated with the air ventilation of the place, the amount of wood burned, and service mode (e.g., all-can-eat). Furthermore, an average of 934 ± 404 CFU m−3 of bacteria was found in all places and Aspergillus, Penicillium, and Cladosphialophora were the most important fungal genera found. Inside kitchens, the concentrations of PM2.5, BC, BrC, bacteria and fungi were 29.6, 3.0, 2.8 µg m−3, 876, and 1261 CFU m−3, with a mean ratio of BrC/PM2.5 of 0.06, that indicates this as a significant source for BrC. Finally, the concentrations of PM and bioaerosols found inside kitchens demonstrate pollution levels much higher than those recommended by national and international guidelines. Consequently, problems associated with poor indoor air quality will only be solved when adequate kitchen designs are considered. From the results of this work is possible to conclude that the building characteristics of kitchen and the burning process carried out are important factors for the concentrations of pollutants analyzed in the indoor air of wood-burning kitchens.

Global warming in tandem with surface albedo reduction caused by black carbon (BC) deposition on glaciers accelerated glacier melting; however, their respective contributions remain unclear. Glaciers in the Qilian Mountains are crucial for the development of oases in the Hexi Corridor; however, their area has decreased by more than 20% over the past half-century. Thus, this study developed a dynamic deposition model for light-absorbing particles (LAPs), coupled with a surface energy and mass balance model. We comprehensively assessed the effects of BC and warming on the melting of a typical glacier in the Qilian Mountains based on the coupled model. BC on the glacier surface caused 13.1% of annual glacier-wide melting, of which directly deposited atmospheric BC reduced the surface albedo by 0.02 and accounted for 9.1% of glacier melting. The air temperature during 2000–2010 has increased by 1.5 °C relative to that during the 1950s, accounting for 51.9% of current glacier melting. Meanwhile, BC emission have increased by 4.6 times compared to those of the early Industrial Revolution recorded in an ice core, accounting conservatively for 6.3% of current glacier melting. Mitigating BC emissions has a limited influence on current glacier melting; however, in the long-term, mitigation should exert a noteworthy impact on glacier melting through the self-purification of glaciers.

Abstract Background There is increasing evidence that exposure to PM2.5 and its constituents is associated with an increased risk of gestational diabetes mellitus (GDM), but studies on the relationship between exposure to PM2.5 constituents and the risk of GDM are still limited. Methods A total of 17,855 pregnant women in Guangzhou were recruited for this retrospective cohort study, and the time-varying average concentration method was used to estimate individual exposure to PM2.5 and its constituents during pregnancy. Logistic regression was used to assess the relationship between exposure to PM2.5 and its constituents and the risk of GDM, and the expected inflection point between exposure to PM2.5 and its constituents and the risk of GDM was estimated using logistic regression combined with restricted cubic spline curves. Stratified analyses and interaction tests were performed. Results After adjustment for confounders, exposure to PM2.5 and its constituents (NO3 −, NH4 +, and OM) was positively associated with the risk of GDM during pregnancy, especially when exposure to NO3 − and NH4 + occurred in the first to second trimester, with each interquartile range increase the risk of GDM by 20.2% (95% CI: 1.118–1.293) and 18.2% (95% CI. 1.107–1.263), respectively. The lowest inflection points between PM2.5, SO4 2−, NO3 −, NH4 +, OM, and BC concentrations and GDM risk throughout the gestation period were 18.96, 5.80, 3.22, 2.67, 4.77 and 0.97 µg/m3, respectively. In the first trimester, an age interaction effect between exposure to SO4 2−, OM, and BC and the risk of GDM was observed. Conclusions This study demonstrates a positive association between exposure to PM2.5 and its constituents and the risk of GDM. Specifically, exposure to NO3 −, NH4 +, and OM was particularly associated with an increased risk of GDM. The present study contributes to a better understanding of the effects of exposure to PM2.5 and its constituents on the risk of GDM.

Light‐absorbing carbonaceous aerosols that dominate atmospheric aerosol warming over India remain poorly characterized. Here, we delve into UV‐visible‐IR spectral aerosol absorption properties at nine PAN‐India COALESCE network sites (Venkataraman et al., 2020, https://doi.org/10.1175/bams‐d‐19‐0030.1). Absorption properties were estimated from aerosol‐laden polytetrafluoroethylene filters using a well‐constrained technique incorporating filter‐to‐particle correction factors. The measurements revealed spatiotemporal heterogeneity in spectral intrinsic and extrinsic absorption properties. Absorption analysis at near‐UV wavelengths from carbonaceous aerosols at these regional sites revealed large near‐ultraviolet brown carbon absorption contributions from 21% to 68%—emphasizing the need to include these particles in climate models. Further, satellite‐retrieved column‐integrated absorption was dominated by surface absorption, which opens possibilities of using satellite measurements to model surface‐layer optical properties (limited to specific sites) at a higher spatial resolution. Both the satellite‐modeled and direct in‐situ absorption measurements can aid in validating and constraining climate modeling efforts that suffer from absorption underestimations and high uncertainties in radiative forcing estimates. Plain Language Summary: Particulate pollution in the atmosphere scatter and absorb incoming solar energy, thus cooling or warming Earth's atmosphere. In developing countries and especially in India, one of the most polluted regions of the world, the extent to which particles can absorb solar energy and warm the atmosphere is not well understood. Here, for the first time, we measure particle absorption simultaneously at nine ground sites across India, in diverse geographical regions with different levels and types of particulate pollution. We find that organic carbon particles exert large absorption at near‐ultraviolet wavelengths, which contain significant solar energy. These light absorbing organic carbon particles, called brown carbon, are emitted in large quantities from biomass burning (e.g., burning crop residue and cooking on wood‐fired stoves). Comparing ground measurements of absorption with satellite‐retrieved measurements that are representative of the entire atmospheric column, we find that near‐surface atmospheric particles can exert significant warming. This study highlights the need to improve climate model simulations of particulate pollution's impact on the climate by incorporating spatiotemporal surface‐level absorption measurements, including absorption by brown carbon particles. Key Points: Measurements at nine regional PAN‐India sites reveal several regions with large aerosol absorption strengthBrown carbon contributes significantly (21%–68%) to near‐ultraviolet absorption, indicating its importance in shortwave light absorptionStrong correlations observed between satellite data and surface absorption indicate future potential in modeling surface absorption [ABSTRACT FROM AUTHOR]

Indoor air quality can be affected by the presence of atmospheric pollutants, which impact severely in human health. The objectives were to show the characterization of particle number (PN0.3–PN2.5), particles mass (PM1.0, PM2.5, PM10), Black Carbon (BC), Brown Carbon (BrC) and bioaerosols (fungi and bacteria) in indoor environments of three pizzerias that have wood ovens as fuel at Londrina, Brazil. Mean Particle mass concentration varied amongst the pizzerias (28.9–42.4 µg m−3 for PM2.5) with the levels of BC and BrC reaching up to 42.9 µg m−3 and 29.4 µg m−3, respectively. These were correlated with the air ventilation of the place, the amount of wood burned, and service mode (e.g., all-can-eat). Furthermore, an average of 934 ± 404 CFU m−3 of bacteria was found in all places and Aspergillus, Penicillium, and Cladosphialophora were the most important fungal genera found. Inside kitchens, the concentrations of PM2.5, BC, BrC, bacteria and fungi were 29.6, 3.0, 2.8 µg m−3, 876, and 1261 CFU m−3, with a mean ratio of BrC/PM2.5 of 0.06, that indicates this as a significant source for BrC. Finally, the concentrations of PM and bioaerosols found inside kitchens demonstrate pollution levels much higher than those recommended by national and international guidelines. Consequently, problems associated with poor indoor air quality will only be solved when adequate kitchen designs are considered. From the results of this work is possible to conclude that the building characteristics of kitchen and the burning process carried out are important factors for the concentrations of pollutants analyzed in the indoor air of wood-burning kitchens. [ABSTRACT FROM AUTHOR]

Fine particulate matter (PM 2.5) has been implicated in various health concerns. However, a comprehensive understanding of the specific PM 2.5 components affecting depression remains limited. This study conducted a Cox proportional-hazards model to assess the effect of PM 2.5 components on the incidence of depression based on the China Health and Retirement Longitudinal Study (CHARLS). Participants with 10-item Center for Epidemiologic Studies Depression Scale (CESD-10) score of 10 or higher were classified as exhibiting depression. Our findings demonstrated a significant positive correlation between long-term exposure to black carbon (BC), sulfate (SO 4 2−), and organic matter (OM) components of PM 2.5 and the prevalence of depression. Per 1 Interquartile Range (IQR) increment in 3-year average concentrations of BC, OM, and SO 4 2− were associated with the hazard ratio (HR) of 1.54 (95 % confidence intervals (CI): 1.44, 1.64), 1.24 (95% CI : 1.16, 1.34) and 1.25 (95% CI : 1.16, 1.35). Notably, females, younger individuals, those with lower educational levels, urban residents, individuals who were single, widowed, or divorced, and those living in multi-story houses exhibited heightened vulnerability to the adverse effects of PM 2.5 components on depression. Firstly, pollutant data is confined to subjects' fixed addresses, overlooking travel and international residence history. Secondly, the analysis only incorporates five fine particulate components, leaving room for further investigation into the remaining fine particulate components in future studies. This study provides robust evidence supporting the detrimental impact of PM 2.5 components on depression. The identification of specific vulnerable populations contributes to a deeper understanding of the underlying mechanisms involved in the relationship between PM 2.5 components and depression. • This study explore the association between PM 2.5 components and depression. • Black carbon, sulfate, and organic matter have significant impacts on depression. • Females, who living in multi-story house were susceptible to the PM 2.5 components. [ABSTRACT FROM AUTHOR]

In 2020, the COVID-19 outbreak led many countries across the globe to introduce lockdowns (LDs) that effectively caused most anthropic activities to either stop completely or be significantly reduced. In Europe, Italy played a pioneeristic role via the early introduction of a strict nationwide LD on March 9th. This study was aimed at evaluating, using both chemical and meteorological data, the environmental response to that occurrence as observed by the Lamezia Terme (LMT) GAW/WMO station in Calabria, Southern Italy. The first 2020 lockdown was therefore used as a "proving ground" to assess CO, CO2, CH4, BC, and NOx concentrations in a rather unique context by exploiting the location of LMT in the context of the Mediterranean Basin. In fact, its location on the Tyrrhenian coast of Calabria and local wind circulation both lead to daily cycles where western-seaside winds depleted in anthropogenic pollutants can be easily differentiated from northeastern-continental winds, enriched in anthropogenic outputs. In addition to this, the first Italian LD occurred during the seasonal transition from winter to spring and, consequently, summer, thus providing new insights on emission outputs correlated with seasons. The findings clearly indicated BC and, in particular, CO as strongly correlated with average daily temperatures, as well as possibly domestic heating. CO2's reduction during the lockdown and consequent increase in the post-lockdown period, combined with wind data, allowed us to constrain the local source of emissions located northeast from LMT. NOx reductions during specific circumstances were consistent with hypotheses from previous research, which linked them to rush hour traffic and other forms of transportation emissions. CH4's stable patterns were consistent with livestock, landfills, and other sources assumed to be nearly constant during LD periods. [ABSTRACT FROM AUTHOR]

The key to a sustainable future is the reduction in humankind's impact on natural systems via the development of new technologies and the improvement in source apportionment. Although days, years and seasons are arbitrarily set, their mechanisms are based on natural cycles driven by Earth's orbital periods. This is not the case for weeks, which are a pure anthropic category and are known from the literature to influence emission cycles and atmospheric chemistry. For the first time since it started data gathering operations, CO (carbon monoxide), CO2 (carbon dioxide), CH4 (methane) and eBC (equivalent black carbon) values detected by the Lamezia Terme WMO/GAW station in Calabria, Southern Italy, have been evaluated via a two-pronged approach accounting for weekly variations in absolute concentrations, as well as the number of hourly averages exceeding select thresholds. The analyses were performed on seven continuous years of measurements from 2016 to 2022. The results demonstrate that the analyzed GHGs (greenhouse gasses) and aerosols respond differently to weekly cycles throughout the seasons, and these findings provide completely new insights into source apportionment characterization. Moreover, the results have been combined into a new parameter: the hereby defined WDWO (Weighed Distribution of Weekly Outbreaks) normalizes weekly trends in CO, CO2, CH4 and eBC on an absolute scale, with the scope of providing regulators and researchers alike with a new tool meant to better evaluate anthropogenic pollution and mitigate its effects on the environment and human health. [ABSTRACT FROM AUTHOR]

The combination of flotation and chemical oxidation is suitable for extracting black carbon (BC) from the soil around coal-fired power plant. In present study, the content of BC was determined by loss on ignition (LOI) method and potassium dichromate volumetric (PDV) method. Four extraction methods of BC were compared and the extracted BC was characterized by XRD, FTIR, SEM, and XPS. The findings reveal that the BC content obtained through the three chemical oxidation methods ranges from 14.51 to 22.25 g·kg-1, 13.10 to 19.28 g·kg-1, and 19.75 to 35.79 g·kg-1, respectively. The BC content obtained by combining flotation and chemical oxidation ranges from 44.04 to 50.60 g·kg-1, indicating that the combination method is more convenient for BC extraction from soil. The BC content measured by the LOI method is higher. The mineral compositions of fly ash from Kanshan power plant (KFA), BC, and soil minerals are similar and main minerals are quartz, magnetite, and hematite. The surface of both KFA and BC mainly comprises elements such as C, O, N, and Si. These results shows that the BC in the soil maybe originate from fly ash of the power plant. It is of great significance for environmental monitoring and pollution control around coal-fired power plants. [ABSTRACT FROM AUTHOR]

This study compares the PM10 (particulate matter of diameter smaller than 10 μm) organic aerosol composition between urban and suburban stations in Heraklion, Crete, during winter 2024 in order to highlight the impact of local anthropogenic activities on urban atmospheric particulate matter pollution. Using an HPLC-ESI-MS Orbitrap analyzer (High Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry) in full MS scan mode at a resolution of 140,000, 48 daily aerosol filter extracts were analyzed in both positive and negative modes, resulting in the detection of 2809 and 3823 features, respectively. Features with at least five times higher intensity in the urban environment compared to the suburban, and p < 0.05, were deemed significant. A correlation with black carbon (r > 0.6) was observed for 71% of significant urban features in positive mode. These features showed a predominance of low O:C ratios (<0.2) and the majority were classified as intermediate volatility organic compounds (IVOCs), indicating fresh primary emissions. A clear urban–suburban distinction was shown by PCA of positive mode features, unlike the negative mode features. Regarding the total intensity of the features, urban samples were on average 55% higher than suburban samples in positive mode and 39% higher in negative mode. This study reveals the molecular profile of locally emitted combustion related organics observed in positive mode in an urban environment. [ABSTRACT FROM AUTHOR]

This study explores the spatial patterns of particulate matter (PM) in the megacity of Delhi. A GRIMM aerosol spectrometer is used to analyze different aerodynamic diameters (PM10, PM2.5, PM1.0), inhalable, thoracic, and alveolic particles, and black carbon (BC) at six prominent locations in Delhi during summer and winter. Additionally, metals (Pb, Fe, Ca, Al, Zn), along with silicon and sulfur, are analyzed using an ED-XRF spectrometer over the sampling locations during the summer season. The sampling site data are interpolated using the Kriging method to generate spatial maps to explore the air pollution problem in Delhi. East Delhi is observed to be the most polluted site, while Guru Gobind Singh Indraprastha University (GGSIPU) is the least polluted site. We further observe a high correlation between Al-Fe, Al-Ca, Zn-Pb, Ca-Fe, and S-Zn, indicating their common source of emission. Aerosols are also found to be highly enriched with metals like Al, S, Fe, Zn, and Pb, suggesting strong anthropogenic sources of these metals. Construction activities, resuspended dust, an increased number of vehicles, faulty agricultural practices, and soil could be recognized as major sources of the particulate concentration in an urban area like Delhi. [ABSTRACT FROM AUTHOR]

Measurements studies have shown that the absorption of radiation by black carbon (BC) increases as the particles age. However, there are significant discrepancies between the measured and modeled absorption enhancement (Eabs), largely due to the simplifications used in modeling the mixing states and shape diversities. We took advantage of chamber experiments on BC aging and developed an efficient method to resolve the particle shape based on the relationship between the coating fraction (ΔDve/Dve,0) and fractal dimension (Df), which can also reflect the variations of Df during the whole BC aging process. BC with externally and partly mixed states (0 ⩽ ΔDve/Dve,0 ⩽ 0.5) can be considered to be uniformly distributed with the Df values of 1.8–2.1, whereas the Df values are constrained in the range 2.2–2.8 for fully mixed states (ΔDve/Dve,0 > 0.5). The morphological parameters (i.e., the effective density and the dynamic shape factor) were compared with the measured values to verify the simulated morphology. The simulated mean deviations of morphological parameters were smaller than 8% for the method resolving the particle shape. By applying a realistic shape and refractive index, the mass absorption cross for fully mixed states can be improved by 11% compared with a simplified core–shell model. Based on our understanding of the influence of Df and ΔDve/Dve,0 on Eabs, we propose a two-stage calibration equation to correct the Eabs values estimated by the core–shell model, which reduces the simulation error in the Mie calculation by 6%–14%. [ABSTRACT FROM AUTHOR]

Grassland ecosystems have evolved alongside fire, a fundamental element that shapes and sustains their ecological balance. Recent research indicates that carbon produced during pyrogenic events in fire-dependent ecosystems may occur in more recalcitrant forms within deeper soil horizons. Notably, refractory organic carbon (ROC) and black carbon (BC) fractions are globally recognised as highly stable components of soil carbon. Here, we examined the impact of prescribed fires on the accumulation of ROC and BC fractions within South African mesic grassland soils. Our findings revealed that while BC remains stable in the soil, exhibiting consistent levels across soil horizons, increased fire frequency led to breakdown of BC in the soil. Greater BC quantities were observed in burn exclusion and prescribed burns with a greater burn interval, suggested as primarily driven by a decline in soil pH. There were no significant differences in ROC within the burn treatments, but there was a notable decrease in ROC with increasing depth increments below 5 cm. The observed trend of ROC accumulation in the top layer of soil, influenced by [ABSTRACT FROM AUTHOR]

The light absorption enhancement (Eabs) of black carbon (BC) coated with non‐BC materials is crucial in the assessment of radiative forcing, yet its evolution during photochemical aging of plumes from biomass burning, the globe's largest source of BC, remains poorly understood. In this study, plumes from open burning of corn straw were introduced into a smog chamber to explore the evolution of Eabs during photochemical aging. The light absorption of BC was measured with and without coating materials by using a thermodenuder, while the size distributions of aerosols and composition of BC coating materials were also monitored. Eabs was found to increase initially, and then decrease with an overall downward trend. The lensing effect dominated in Eabs at 520 nm, with an estimated contribution percentages of 47.5%–94.5%, which is far greater than light absorption of coated brown carbon (BrC). The effects of thickening and chemical composition changes of the coating materials on Eabs were evaluated through comparing measured Eabs with that calculated by the Mie theory. After OH exposure of 1 × 1010 molecules cm−3 s, the thickening of coating materials led to an Eabs increase by 3.2% ± 1.6%, while the chemical composition changes or photobleaching induced an Eabs decrease by 4.7% ± 0.6%. Simple forcing estimates indicate that coated BC aerosols exhibit warming effects that were reduced after aging. The oxidation of light‐absorbing CxHy compounds, such as polycyclic aromatic hydrocarbons (PAHs), to CxHyO and CxHyO>1 compounds in coating materials may be responsible for the photobleaching of coated BrC. Plain Language Summary: Understanding how black carbon (BC) coated with non‐BC materials affects light absorption is crucial for assessing its impact on the Earth's climate. However, there is limited knowledge about how this process changes when BC, particularly from biomass burning, is exposed to light. Biomass burning is a significant global source of BC. This study investigated the changes in light absorption of BC from burning corn straw as it aged in a controlled environment. We measured the light absorption of BC with and without its coating materials. Our results showed that the main cause of increased light absorption was the lensing effect of the coating materials, which was more significant than the light absorption by the coating materials themselves. We also discovered that as the coating materials thickened, BC absorbed more light. However, changes in the chemical composition of the coating materials led to a decrease in total absorption. These findings suggest that while coated BC initially has a warming effect on the climate, this effect diminished as the BC ages. The decrease is likely due to the breakdown of light‐absorbing compounds in the coating materials, such as polycyclic aromatic hydrocarbons (PAHs). Key Points: Photochemical evolution of light absorption enhancement (Eabs) of black carbon from corn straw burning was studied in a chamberAfter an initial increase Eabs decreased and then remained unchanged during photochemical agingThe photobleaching impacted more on Eabs than the thickening of coating aerosols during photochemical aging [ABSTRACT FROM AUTHOR]

Background: There is increasing evidence that exposure to PM2.5 and its constituents is associated with an increased risk of gestational diabetes mellitus (GDM), but studies on the relationship between exposure to PM2.5 constituents and the risk of GDM are still limited. Methods: A total of 17,855 pregnant women in Guangzhou were recruited for this retrospective cohort study, and the time-varying average concentration method was used to estimate individual exposure to PM2.5 and its constituents during pregnancy. Logistic regression was used to assess the relationship between exposure to PM2.5 and its constituents and the risk of GDM, and the expected inflection point between exposure to PM2.5 and its constituents and the risk of GDM was estimated using logistic regression combined with restricted cubic spline curves. Stratified analyses and interaction tests were performed. Results: After adjustment for confounders, exposure to PM2.5 and its constituents (NO3−, NH4+, and OM) was positively associated with the risk of GDM during pregnancy, especially when exposure to NO3− and NH4+ occurred in the first to second trimester, with each interquartile range increase the risk of GDM by 20.2% (95% CI: 1.118–1.293) and 18.2% (95% CI. 1.107–1.263), respectively. The lowest inflection points between PM2.5, SO42−, NO3−, NH4+, OM, and BC concentrations and GDM risk throughout the gestation period were 18.96, 5.80, 3.22, 2.67, 4.77 and 0.97 µg/m3, respectively. In the first trimester, an age interaction effect between exposure to SO42−, OM, and BC and the risk of GDM was observed. Conclusions: This study demonstrates a positive association between exposure to PM2.5 and its constituents and the risk of GDM. Specifically, exposure to NO3−, NH4+, and OM was particularly associated with an increased risk of GDM. The present study contributes to a better understanding of the effects of exposure to PM2.5 and its constituents on the risk of GDM. [ABSTRACT FROM AUTHOR]

In recent years, the role of the atmosphere in the formation of the chemical composition of water in Lake Baikal and its tributaries has been increasing. In this regard, the study of equivalent black carbon (eBC) in the air above the lake and its coast has an important practical application. This paper presents the results of the mass concentration of eBC and submicron aerosol in the air above the water area of Lake Baikal, which were obtained during expeditions onboard research vessels in the summer of 2019 and 2023. We analyzed the data from the coastal monitoring station Listvyanka. To measure eBC, an MDA-02 aethalometer was used in the water area of the lake, and a BAC-10 aethalometer at the Listvyanka station. The background level of the eBC concentration in the air at different areas of the lake ranged between 0.15 and 0.3 µg m−3. The results of the two expeditions revealed the influence of the coastal settlements and the air mass transport along the valleys of the lake's large tributaries on the five- to twentyfold growth of the eBC concentration in the near-water atmosphere. In the diurnal dynamics of eBC near settlements, we recorded high values in the evening and at night. In background areas, the diurnal dynamics were poorly manifested. In the summer of 2019, there were smoke plumes in the water area of Lake Baikal from distant wildfires and a local fire site on the east coast of the lake. The eBC concentration increased to 5–6 µg m−3, which was 10 to 40 times higher than the background. The long-range transport of plumes from coal-fired thermal power plants in large cities of the region made the major contribution to the eBC concentration at «Listvyanka» in winter, which data on aerosol, gas impurities, and meteorological parameters confirmed. [ABSTRACT FROM AUTHOR]

This study evaluates the engine performance and life-cycle emissions of hydrogen enriched LNG as a pragmatic solution to more rapidly introducing hydrogen as marine fuel, while waiting for pure hydrogen fuel infrastructure to be built. Engine experiments in a 4-stroke marine diesel engine operating with a spark-ignited pre-chamber ignition system were conducted, and a wide range of engine exhaust emissions measurements including CH 4 , N 2 O, H 2 , and particulate matter (black carbon emission evaluation) were recorded at varying engine loads. The fuel compositions ranged from pure LNG operation to pure hydrogen operation and also included pure conventional diesel fuel oil for comparison. The research methodology integrates engine tests with a full well-to-wake life-cycle assessment (LCA). The impact of using 39.6% hydrogen by energy fraction in natural gas reduced GHG emission by 37.8% on a life-cycle basis at 50% engine load, which could mean a significant reduction of GHG emissions. • Analysis of Hydrogen enriched LNG GHG impact through LCA approach (Well-to-Wake). • A mid-term solution to introduce Hydrogen as maritime fuel. • Experiment of Hydrogen enriched LNG on maritime scale test engine laboratory. • GHG analysis of measured emission data for CO, CO 2 , N 2 O, NO X , PM, CH 4 , H 2. • Detailed climate impact of CH 4 , N 2 O and Black Carbon (BC). [ABSTRACT FROM AUTHOR]

• The risks of cardiovascular and respiratory diseases decline with PM 2.5 in Beijing. • Short periods of lockdown have little effect on long-term changes in health risks. • Ni, Cr, Pb, As, and BC in PM 2.5 show high carcinogenic risks in Beijing. • Health risks from traffic and biomass burning are more prominent in Beijing. • PM 2.5 mass concentration has decreased, but the risks of toxic components are still high. A comprehensive health risk assessment of PM 2.5 is meaningful to understand the current status and directions regarding further improving air quality from the perspective of human health. In this study, we evaluated the health risks of PM 2.5 as well as highly toxic inorganic components, including heavy metals (HMs) and black carbon (BC) based on long-term observations in Beijing from 2019 to 2021. Our results showed that the relative risks of chronic obstructive pulmonary disease, lung cancer, acute lower respiratory tract infection, ischemic heart disease, and stroke decreased by 4.07%-9.30% in 2020 and 2.12%-6.70% in 2021 compared with 2019. However, they were still at high levels ranging from 1.26 to 1.77, in particular, stroke showed the highest value in 2021. Mn had the highest hazard quotient (HQ , from 2.18 to 2.56) for adults from 2019 to 2021, while Ni, Cr, Pb, As, and BC showed high carcinogenic risks (CR > 1.0×10−6) for adults. The HQ values of Mn and As and the CR values of Pb and As showed constant or slight upwards trends during our observations, which is in contrast to the downward trends of other HMs and PM 2.5. Mn, Cr, and BC are crucial toxicants in PM 2.5. A significant shrink of southern region sourcesof HMs and BCshrank suggests the increased importance of local sources. Industry, dust, and biomass burning are the major contributors to the non-carcinogenic risks, while traffic emissions and industry are the dominant contributors to the carcinogenic risks in Beijing. [Display omitted] [ABSTRACT FROM AUTHOR]

Over the years, the Cape Peninsula has seen a rise in the number of fires that occur seasonally. This study aimed to investigate the extent of fire spread and associated damages during the 2023/2024 Cape Peninsula fire events. Remote sensing datasets from Sentinel-5P, Sentinel-2, Moderate Resolution Imaging Spectroradiometer (MODIS), and Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) were used. Most of the fires on the northern side of the Cape Peninsula had a short burning span of between 6 and 12 h, but fires with a duration of 12–24 h were minimal. The northern area is composed of low forests and thickets as well as fynbos species, which were the primary fuel sources. Excessive amounts of carbon monoxide (CO) and black carbon (BC) emissions were observed. High speeds were observed during the period of the fires. This is one of the factors that led to the spread of the fire. Relative humidity at 60% was observed, indicating slightly dry conditions. Additionally, the Leaf Water Content Index (LWCI) indicated drier vegetation, enhancing fire susceptibility. High temperatures, low moisture and strong winds were the main drivers of the fire. The Normalized Burn Ratio (NBR) values for the targeted fires showed values close to −1, which signifies presence of a fire scar. The study can be of use to those in the fire management agencies and biodiversity conservation in the region. [ABSTRACT FROM AUTHOR]

In the context of China's "dual carbon" goal, emissions of air pollutants are expected to significantly decrease in the future. Thus, the direct climate effects of black carbon (BC) aerosols in East Asia are investigated under this goal using an updated regional climate and chemistry model. The simulated annual average BC concentration over East Asia is approximately 1.29 μg/m3 in the last decade. Compared to those in 2010–2020, both the BC column burden and instantaneous direct radiative forcing in East Asia decrease by more than 55% and 80%, respectively, in the carbon peak year (2030s) and the carbon neutrality year (2060s). Conversely, the BC effective radiative forcing (ERF) and regional climate responses to BC exhibit substantial nonlinearity to emission reduction, possibly resulting from different adjustments of thermal‐dynamic fields and clouds from BC‐radiation interactions. The regional mean BC ERF at the tropopause over East Asia is approximately +1.11 W/m2 in 2010–2020 while negative in the 2060s. BC‐radiation interactions in the present‐day impose a significant annual mean cooling of −0.2 to −0.5 K in central China but warming +0.3 K in the Tibetan Plateau. As China's BC emissions decline, surface temperature responses show a mixed picture compared to 2010–2020, with more cooling in eastern China and Tibet of −0.2 to −0.3 K in the 2030s, but more warming in central China of approximately +0.3 K by the 2060s. The Indian BC might play a more important role in East Asian climate with reduction of BC emissions in China. Plain Language Summary: Black carbon (BC) aerosols, which are among the air pollutants that will be reduced in China under the "dual carbon" goal, can have an impact on the regional climate by absorbing solar radiation. We use a regional climate model to simulate the climate effect of BC over East Asia under the "dual carbon" goal of China. The results showed that the BC concentration and column burden in East Asia, as well as the instantaneous direct radiative forcing, will decrease significantly under future regional emission reduction policies. However, the effective radiative forcing of BC and regional climate responses do not exhibit simple linear relationships with emissions. The BC‐induced atmospheric thermal‐dynamic anomalies are the main drivers of this nonlinearity. Similarly, BC emissions from India might also influence the East Asian climate. Key Points: The East Asian black carbon (BC) loadings and instantaneous direct radiative forcings significantly decrease under the "dual carbon" goal of ChinaThe BC induced regional climate changes show nonlinear responses to the BC emission reductionThe Indian BC might play an increasingly important role in East Asian climate with decreasing BC emissions in China [ABSTRACT FROM AUTHOR]

AbstractBlack carbon was widely researched due to its significant role on the global carbon cycle and contaminant transport, and most people were concerned about the property of the dissolved black carbon from black carbon. In this work, we focused on the research of the residual those of black carbon. Two kinds of black carbon originated from peanut shell and bamboo were prepared and the corresponding residual black carbons were also obtained by the ultrasonic dissolution process. It was found the chemical and structure properties of residual black carbon changed a lot compared to black carbon. Using methylene blue as a target contaminant, the adsorption capacity of methylene blue by the residual black carbon was greater than that of black carbon. The adsorption capacity of black carbon-bamboo for methylene blue increased from 11.1 mg/g to 16 mg/g after the dissolution process, and the adsorption capacity of black carbon-peanut shell for methylene blue increased from 14 mg/g to 23 mg/g. The various influencing factors, such as the pH, initial concentration, temperature and adsorbent dosage, were systematically studied. The black carbons derived from peanut shell before and after the ultrasonic dissolution process both showed greater adsorption capacities for methylene blue. To further elucidate the methylene blue adsorption process, different kinds of isotherm and kinetics models were applied to simulate the experimental data. The results indicated that the Langmuir isotherm model was suitable to all the carbons before and after the ultrasonic dissolution process, and the pseudo-second-order model showed great simulation for the adsorption of methylene blue. In addition, the analysis of the thermodynamic study revealed that the adsorption processes of methylene blue were endothermic and spontaneous. Overall, results obtained from this work revealed the black carbon after been dissolved showed better adsorption capacity for contaminant. [ABSTRACT FROM AUTHOR]

The atmospheric concentrations of particulate pollution are of great scientific concern due to their impact on both human health and environment. This study aimed to investigate the concentration of black carbon (BC), particulate matter with an aerodynamic diameter of less than 10 micrometres (PM10) and nitrogen oxides (NOx) at an urban background environment throughout the year, and understand the impact of winter heating and meteorology on its concentration level. The campaign covered heating and non-heating periods, from 1 June 2021 to 31 May 2022. During the heating period, the mass concentrations of BC, PM10 and NOx were 1.17, 24.9 and 19.4 μg m–3, respectively. The analysis revealed that the mass concentrations of BC and NOx were 1.9 and 1.4 times greater during the heating period, respectively, compared to the non-heating period. In contrast, PM10 remained almost constant during the heating (19.4 μg m–3 ) and non-heating periods (20.0 μg m–3). Throughout the year, the BC mass concentration was dominated by BCFF (71.2%) originating from fossil fuel combustion with a maximum (8.43 μg m–3) during the heating period. Moreover, wind speed presented a weak negative correlation with BC (r = –0.40), PM10 (r = –0.19) and NOx (r = –0.40) during the heating period. [ABSTRACT FROM AUTHOR]

This study aims to delineate the characteristics of black carbon (BC) in the atmosphere over the urban background environment in Vilnius (Lithuania) from 1 June 2021 to 31 May 2022 using aethalometer (Magee Scientific) measurements. The annual mean concentrations of BC originating from fossil fuels (BCff) and from biomass burning (BCbb) were found to be 0.63 μg m−3 with a standard deviation (SD) of 0.67 μg m−3 and 0.27 µg m−3 (0.35 μg m−3). The further findings highlight the dominance of fossil-fuel-related BC throughout the study period (71%) and the seasonal variability of BC pollution, with biomass-burning-related BC making the largest contribution during the summer season (41%) and the smallest contribution during autumn (23%). This information provides valuable insights into the sources and dynamics of BC pollution in the region. The sources and composition of BC on the days with the highest pollution levels were influenced by a combination of local and regional factors in every season. Additionally, this study employs an advanced approach to understanding urban BC pollution by focusing on high-pollution days (18), identified based on a daily mean BC mass concentration exceeding the 95th percentile, alongside an analysis of overall seasonal and diurnal variations. This methodology surpasses many those of previous urban BC studies, offering a comprehensive examination of the sources and composition of BC pollution. [ABSTRACT FROM AUTHOR]

Residential wood combustion (RWC) is a significant source of gaseous and particulate emissions causing adverse health and environmental effects. Several factors affect emissions, but the effects of the fuel wood species on emissions are currently not well understood. In this study, the Nordic wood species (named BirchA, BirchB, Spruce, SpruceDry, Pine and Alder) were combusted in a modern stove, and the emissions were studied. The lowest emissions were obtained from the combustion of BirchA and the highest from Spruce and Alder. The fine particle mass (PM2.5) was mainly composed of elemental carbon (50–70% of PM2.5), which is typical in modern appliances. The lowest PAH concentrations were measured from BirchA (total PAH 107 µg/m3) and Pine (250 µg/m3). In the ignition batch, the PAH concentration was about 4-fold (416 µg/m3). The PAHs did not correlate with other organic compounds, and thus, volatile organic compounds (VOCs) or organic carbon (OC) concentrations cannot be used as an indicator of PAH emissions. Two birch species from different origins with a similar chemical composition but different density produced partially different emission profiles. This study indicates that emission differences may be due more to the physical properties of the wood and the combustion conditions than to the wood species themselves. [ABSTRACT FROM AUTHOR]

Mobile monitoring is used as an additional tool to collect air quality data at a high spatial resolution and to complement data from fixed air quality stations. Citizens are interested in contributing to air quality monitoring, and while the availability of low-cost air quality sensors can create opportunities to measure the air quality at a high spatial resolution, the data are often of lower quality, and sensors that measure combustion-related aerosols (like black carbon) are not commonly available. Mobile monitoring using a mid-range instrument can fill this gap. We present the results of a mobile BC (black carbon) monitoring campaign performed by citizens in Mechelen as part of a local citizen observatory (CO), Meet Mee Mechelen, initiated as part of the European H2020 project, Ground Truth 2.0. The goal of the study was two-fold: (1) to propose and evaluate a mobile monitoring method (data collection and data processing) to construct pollution maps of BC concentrations and (2) to demonstrate how to organize community-based air quality monitoring to measure both the spatial and temporal variations in air pollution levels. Measurements were taken during peak hours in four campaigns characterized by different meteorological conditions: October–November 2017, February–March 2018, June–July 2018 and September 2018. The results show large spatial and temporal variabilities. Spatial variability is influenced by traffic volume, stop-and-go traffic and also the building environment and the distance of biking paths from road traffic. The four different campaigns show similar spatial patterns, but due to background and meteorological influences, the absolute concentrations differ between seasons. A rescaling method using data from fixed stations in the air quality monitoring network (AQMN) was presented to construct maps representative of longer periods. This paper shows that mobile measurements can be used by CO to assess the spatial variability of air quality in a city. The data can be used to evaluate mobility plans, carry out hot spot detection, evaluate the exposure of cyclists as a function of cycling infrastructure and perform model validation. However, it is important to use high-quality instruments and apply the correct measurement methodology (number of repetitions, season) to obtain meaningful data. [ABSTRACT FROM AUTHOR]