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Based on the geographic information system (GIS) software and the application of the black carbon (BC) and fine particulate matter ( PM 2.5 ) ratio method, this paper analyzed and calculated the national BC distribution from 2015 to 2017 and evaluated the national human exposure to BC. The results showed that from 2015 to 2017, 2/3 of the national land area and nearly half of the population were exposed to 1–3 μ g / m 3 , and the area and population exposed to a concentration less than 2 μ g / m 3 increased yearly, while the area and population exposed to a concentration higher than 9 μ g / m 3 decreased yearly. The estimated economic loss showed that 77.3% of the targeted districts or counties claimed a loss per square kilometer of 50 million Chinese Yuan (CNY) or less from the perspective of annual changes, and districts and counties in Beijing-Tianjin-Hebei and Hunan with annual losses between 50 and 500 million CNY showed an increasing trend. The BC ratio (the proportion of BC economic loss to GDP) of Beijing-Tianjin-Hebei and Hunan also showed an increasing trend yearly. [ABSTRACT FROM AUTHOR]

In the context of global warming, the future spatiotemporal distribution of aerosols in China is a common concern of the government and the scientific community. In this study, the regional climate model RegCM4 is used to simulate the spatiotemporal distribution of anthropogenic aerosols including sulfate, black carbon, and organic carbon in China around 2030 under the RCP4.5 and RCP8.5 scenarios and estimate the contributions of climate difference, emission difference, and extra-regional transport difference to the change of anthropogenic aerosol concentration in the study area. The results show that the annual average concentrations of anthropogenic aerosols around 2030 decreased significantly with respect to those around 2010, and the decrease amplitude of black carbon surface concentration is the smallest, especially in the RCP8.5 scenario. The annual averages for sulfate, black carbon, and organic carbon surface concentrations in the central and eastern parts of China will be 8.5, 1.7, and 3.7 μg m−3, respectively, under the RCP4.5 scenario, whereas 10.0, 2.2, and 4.4 μg m−3, respectively, under the RCP8.5 scenario. The surface concentration of sulfate is higher in summer and spring, while lower in winter and autumn. The surface concentrations of black carbon and organic carbon are higher in winter and lower in other seasons. The results of sensitivity experiments demonstrate that the future difference in local emissions between RCP8.5 and RCP4.5 scenarios has the greatest impact on the anthropogenic aerosol concentrations throughout China, while the effects of future climate difference and extra-regional transport difference are much smaller around 2030. For the aerosol column burdens, the effect of future local emission difference between the two scenarios is still dominant, and the effect of extra-regional transport difference becomes very significant during spring and winter for organic carbon and black carbon. The results of this paper suggest that the impacts of future climate difference and extra-regional transport difference between RCP8.5 and RCP4.5 scenarios on anthropogenic aerosols are non-negligible in certain regions and seasons besides the impact of future local emission difference in China around 2030. [ABSTRACT FROM AUTHOR]

Potential risks to people's health should receive much more attention with an increasing compound pollution in urban river ecological landscape. In this paper, the concentrations of 8 heavy metals (HMs, V, Cr, Mn, Co, Ni, Zn, As and Pb), black carbon (BC, char and soot) and polycyclic aromatic hydrocarbons (PAHs) were determined in soils and river sediments collected from 72 sampling sites along the Chan-Ba River, and also were evaluated, concerning source analysis and health risks. The results indicate that the concentrations of BC and PAHs varied seasonally, and the concentration of HMs showed little seasonal variation. The concentration of BC was higher in winter than in summer, while that of PAHs was higher in summer than in winter. These pollutants were spatial heterogeneity. The concentrations of these pollutants in the middle reaches of the Ba River were much higher than those in the upper and lower reaches. These changes are attributed to the spatial-temporal distribution of local pollutant emissions and the characteristics of regional pollutant transportation and deposition. Source and cluster analysis revealed that BC, HMs and PAHs were pyrogenic (including coal and biomass combustions, vehicular emissions). The evaluation of health risk of PAHs and HMs revealed that the cancer risk for adults and children was higher than the 10-6 and lower than 10-4 implying low to moderate risk, and it is noted that there are higher potential risks of Phe and Flu at the middle reaches in summer and As at the lower reaches in Autumn. Therefore, pollution prevention and monitoring, classification management and control mechanisms in designated river basins are necessary to ensure the quality and safety of the ecological environment in the Chan & Ba River basin. [ABSTRACT FROM AUTHOR]

This paper presents preliminary scientific analytical results and discussion on the murals unearthed at the Shimao Site in Shenmu County, Shaanxi Province. The murals were composed of pigment layer, plaster base layer and daub layer. The pigments used include hematite, goethite, glauconite and carbon black. Same with the floor plaster layer of the house foundations in the site, the plaster layer of murals is made of calcium carbonate. For the painting procedure, a draft had firstly been designed by engraved lines, and then the murals were painted with various pigments. A tentative comparative study shows that the manufacturing technology and painting techniques of the Shimao mural are similar to that of the murals of the Han and Tang Dynasties. It indicates that the fundamental manufacturing technology of mural had probably been established in the Erlitou Period at latest, which was just followed and enriched over the Han and Tang Dynasties. [ABSTRACT FROM AUTHOR]

Earth system models (ESMs) participating in the latest Coupled Model Intercomparison Project Phase 6 (CMIP6) simulate various components of fine particulate matter (PM2.5) as major climate forcers. Yet the model performance for PM2.5 components remains little evaluated due in part to a lack of observational data. Here, we evaluate near-surface concentrations of PM2.5 and its five main components over China as simulated by 14 CMIP6 models, including organic carbon (OC; available in 14 models), black carbon (BC; 14 models), sulfate (14 models), nitrate (4 models), and ammonium (5 models). For this purpose, we collect observational data between 2000 and 2014 from a satellite-based dataset for total PM2.5 and from 2469 measurement records in the literature for PM2.5 components. Seven models output total PM2.5 concentrations, and they all underestimate the observed total PM2.5 over eastern China, with GFDL-ESM4 (- 1.5 %) and MPI-ESM-1-2-HAM (- 1.1 %) exhibiting the smallest biases averaged over the whole country. The other seven models, for which we recalculate total PM2.5 from the available component output, underestimate the total PM2.5 concentrations partly because of the missing model representations of nitrate and ammonium. Concentrations of the five individual components are underestimated in almost all models, except that sulfate is overestimated in MPI-ESM-1-2-HAM by 12.6 % and in MRI-ESM2-0 by 24.5 %. The underestimation is the largest for OC (by - 71.2 % to - 37.8 % across the 14 models) and the smallest for BC (- 47.9 % to - 12.1 %). The multi-model mean (MMM) reproduces the observed spatial pattern for OC (R = 0.51), sulfate (R = 0.57), nitrate (R = 0.70) and ammonium (R = 0.74) fairly well, yet the agreement is poorer for BC (R = 0.39). The varying performances of ESMs on total PM2.5 and its components have important implications for the modeled magnitude and spatial pattern of aerosol radiative forcing. [ABSTRACT FROM AUTHOR]

Rapid economic and energy growth in Asia has led to change in the loadings of black carbon (BC) in the last two decades. This work uses remotely sensed column absorbing aerosol optical depth to quantify BC loading day-by-day and grid-to-grid. Variance maximization is used to uniquely compute an unbiased set of observations of remotely sensed NO2 in space and time of urban and suburban sources, including regions with changing energy and industry. An inversely applied probabilistic MIE algorithm constrains the size, mixing state, and number of BC using four spectral observations. Significant differences in the particle size and mixing state are identified and attributed including: a drop around 2012 when China's national air pollution policies were adopted, a drop ahead of the 2008 Olympics, and flattening from 2015 onward. A case of simultaneous reduction in BC mass and increase in BC number demonstrates PM2.5 controls may not fully control BC. [ABSTRACT FROM AUTHOR]

Black carbon (BC) plays an important role in air quality, public health, and climate, but its long-term variations in emissions and health effects have been insufficiently understood for China. Here, we present the spatiotemporal evolution of BC emissions and the associated premature mortality in China during 2000–2020 based on an integrated framework combining satellite observations from the Ozone Monitoring Instrument (OMI), an extreme gradient boosting (XGBoost) algorithm, a "top-down" inversion approach, and an exposure–response model. We found that the "bottom-up" approach most likely underestimated BC emissions, particularly in less developed western and remote areas. Pollution controls were estimated to reduce the annual BC emissions by 26 % during 2010–2020, reversing the 8 % growth during 2000–2010. BC emissions in the main coal-producing provinces declined by 2010 but rebounded afterwards. By contrast, provinces with higher economic and urbanization levels experienced emission growth (0.05–0.10 Mg km -2 yr -1) by 2010 and declined greatly (0.07–0.23 Mg km -2 yr -1) during 2010–2020. The national annual BC-associated premature mortality ranged between 733 910 (95 % confidence interval: 676 790–800 250) and 937 980 cases (864 510–1 023 400) for different years. The changing BC emissions contributed to an increase of 78 590 cases (72 520–85 600) during 2000–2005 and a decrease of 133 360 cases (123 150–145 180) during 2010–2015. Strategies differentiated by region are needed for further reducing BC emissions and their health and climate impacts. [ABSTRACT FROM AUTHOR]

The Aethalometer is a widely used instrument for black carbon (BC) mass concentration and light absorption coefficient (babs) measurements around the world. However, field intercomparison of the two popular models, dual-spot (AE33) and single-spot (AE31) Aethalometers, remains limited; in addition, the difference in secondary brown carbon (BrCsec) light absorption estimation between the two models is largely unknown. We performed full-year collocated AE33 and AE31 measurements in a megacity in southern China – Guangzhou. The babs values agree well between the two Aethalometers (R2 > 0.95), with AE33 / AE31 slopes ranging from 0.87 to 1.04 for seven wavelengths. AE33 consistently exhibits lower limits of detection (LODs) than AE31 for time resolutions of 2 to 60 min. The AE33 / AE31 slope for equivalent BC (eBC) was 1.2, implying the need for site-specific post-correction. The absorption Ångström exponent (AAE) obtained from different approaches does not agree very well between the two models, with the biggest discrepancy found in AAE880/950. The estimated BrCsec light absorption at 370 nm (babs370_BrCsec) was calculated using the minimum- R -squared (MRS) method for both Aethalometers. The babs370_BrCsec comparison yields a slope of 0.78 and an R2 of 0.72 between the two models, implying a non-negligible inter-instrument difference. This study highlights the high consistency in babs but less so in AAE between AE31 and AE33 and reveals site-specific correction for eBC estimation and non-negligible difference in BrCsec estimation. The results are valuable for data continuity in long-term Aethalometer measurements when transitioning from the older (AE31) to the newer (AE33) model, as anticipated in permanent global-climate and air-quality stations. [ABSTRACT FROM AUTHOR]

Black carbon (BC) aerosols have a considerable impact on humans because they not only cause environmental pollution and reduce visibility but also harm human health. During the heating season in northern China, a large amount of coal is burned for heating, producing a large amount of BC. There are few studies on BC properties during the heating season. In this paper, BC is measured optically, so it is referred to as equivalent black carbon (EBC). This paper investigated EBC properties in depth during the heating and nonheating seasons of a typical urban environment in China with two years of EBC measurements. The results show that: (1) EBC aerosol concentrations during the heating season were significantly higher than those during the nonheating season. (2) The main sources of EBC aerosols throughout the year are liquid sources. During the heating season, solid sources (coal and biomass combustion) are dominant. (3) The proportion of brown carbon (BrC) produced by biomass energy during the heating season is greater than that during the nonheating season. (4) The resulting backward trajectory indicates that a large portion of the high EBC aerosol concentration sources originate from northern and northwestern China. Our results reveal that the characteristics and sources of EBC in the urban environment of northern China vary widely, suggesting that different measures should be taken to reduce BC aerosol concentrations during heating and nonheating seasons. [ABSTRACT FROM AUTHOR]

Background: Black carbon (BC) encompasses a range of carbonaceous materials––including soot, char, and charcoal––derived from the incomplete combustion of fossil fuels and biomass. Urban soils can become enriched in BC due to proximity to these combustion sources. We conducted a literature review of BC in urban soils globally and found 26 studies reporting BC and total organic carbon (TOC) content collected to a maximum of 578 cm depth in urban soils across 35 cities and 10 countries. We recorded data on city, climate, and land use/land cover characteristics to examine drivers of BC content and contribution to TOC in soil. Results: All studies were conducted in the northern hemisphere, with 68% of the data points collected in China and the United States. Surface samples (0–20 cm) accounted for 62% of samples in the dataset. Therefore, we focused our analysis on 0–10 cm and 10–20 cm depths. Urban soil BC content ranged from 0–124 mg/g (median = 3 mg/g) at 0–10 cm and from 0–53 mg/g (median = 2.8 mg/g) at 10–20 cm depth. The median proportional contribution of BC to TOC was 23% and 15% at 0–10 cm and 10–20 cm, respectively. Surface soils sampled in industrial land use and near roads had the highest BC contents and proportions, whereas samples from residential sites had among the lowest. Soil BC content decreased with mean annual soil temperature. Conclusions: Our review indicates that BC comprises a major fraction (nearly one quarter) of the TOC in urban surface soils, yet sampling bias towards the surface could hide the potential for BC storage at depth. Land use emerged as an importer driver of soil BC contents and proportions, whereas land cover effects remain uncertain. Warmer and wetter soils were found to have lower soil BC than cooler and drier soils, differences that likely reflect soil BC loss mechanisms. Additional research on urban soil BC at depth and from diverse climates is critical to better understand the role of cities in the global carbon cycle. [ABSTRACT FROM AUTHOR]

Textile dyeing industries using conventional small molecular weight organic dyes generate large quantities of refractory wastewater every day, which causes serious problems to the environment. Here, a promising clean method for textile colouration without using organic dyes is reported, which consists of two parts: 1, a darkness control system based on immobilizing functionalized carbon black nanoparticles onto cotton fabric via radiation-initiated co-graft polymerization with vinyl monomers; 2, an approximate RGB (red, green and blue) colour control system by immobilizing cobalt blue, cobalt green, iron oxide red nanoparticles onto cotton fabric that can colourate the cotton fabric with not only the three primary RGB colours but also a series of different colours by blending the three-primary RGB colours. The colour of the cotton fabric can be controlled precisely by changing the degree of grafting of the nanoparticles. The strong covalent bonds network between the nanoparticles and the cotton fabric prevents the release of nanoparticles during usage and the colour remains intact even after intense laundering, equivalent to 100 domestic laundering cycles. The wastewater when using this novel dyeing method is significantly cleaner than the real dyeing industry wastewater and can be discharged without further treatment, taking into consideration directives defined by China and other major textile-producing countries. [ABSTRACT FROM AUTHOR]

Earth system models (ESMs) participating in the latest Coupled Model Intercomparison Project Phase 6 (CMIP6) simulate various components of fine particulate matter (PM2.5) as major climate forcers. Yet the model performance for PM2.5 components remains little evaluated due in part to lack of observational data. Here, we evaluate near-surface concentrations of PM2.5 and its five main components over China as simulated by fourteen CMIP6 models, including organic carbon (OC, available in 14 models), black carbon (BC, 14 models), sulfate (14 models), nitrate (4 models), and ammonium (5 models). For this purpose, we collect observational data between 2000 and 2014 from a satellite-based dataset for total PM2.5 and from 2469 measurement records in the literature for PM2.5 components. Seven models output total PM2.5 concentrations, and they all underestimate the observed total PM2.5 over eastern China, with GFDL-ESM4 (–1.5 %) and MPI-ESM-1-2-HAM (–1.1 %) exhibiting the smallest biases averaged over the whole country. The other seven models, for which we recalculate total PM2.5 from the available components output, underestimate the total PM2.5 concentrations, partly because of the missing model representations of nitrate and ammonium. Concentrations of the five individual components are underestimated in almost all models, except that sulfate is overestimated in MPI-ESM-1-2-HAM by 12.6 % and in MRI-ESM2-0 by 24.5 %. The underestimation is the largest for OC (by –71.2 % to –37.8 % across the 14 models) and the smallest for BC (–47.9 % to –12.1 %). The multi-model mean (MMM) reproduces fairly well the observed spatial pattern for OC (R = 0.51), sulfate (R = 0.57), nitrate (R = 0.70) and ammonium (R = 0.75), yet the agreement is poorer for BC (R = 0.39). The varying performances of ESMs on total PM2.5 and its components have important implications for the modeled magnitude and spatial pattern of aerosol radiative forcing. [ABSTRACT FROM AUTHOR]

Abstract An emission inventory of carbonyl sulfide (COS) from primary anthropogenic sources in China was compiled from 2010 to 2015. The national total emission was estimated at 174 Gg S yr−1 in 2015, with an annually average sustainable growth rate of 7.2% from 2010 to 2015. Industrial sources, biomass burning, coal combustion, agricultural sources and vehicle exhaust contributed 68.2%, 22.0%, 6.1%, 2.2%, and 1.5%, respectively, of total COS emissions in 2015. Aluminum production, carbon black production, titania production, coke production, pulp and paper industry, were the main industrial sources of COS, with the emission about 118 Gg S yr−1 COS in 2015, accounting for 98.5% of total direct emissions from the Chinese industry. The distribution of COS emissions in China showed significant differences at the provincial level. In Shandong and Xinjiang province, they were much bigger than other provinces, with total emissions of 31 and 15 Gg S yr−1, respectively. Uncertainty analysis of COS emission inventories showed that the emission range was 70–267 Gg S yr−1 at a 95% confidence interval. In this study, COS emissions in China were much higher than prior underestimated estimations, even for Asian and global emissions, which could be resolved part of missing sources in the global COS budget. Graphical abstract Image 1 Highlights • A COS emission inventory from primary anthropogenic sources in China was compiled. • Aluminum production contributed about a half of anthropogenic COS emission in China. • An extremely uneven spatial characteristics of COS emissions within China was found. • COS emissions in China were much higher than prior estimations, even for Asian and global emissions. • COS emissions in China could be resolved part of missing sources in the global COS budget. COS emissions in China were much higher than prior underestimated estimations, even for Asian and global emissions, which could be resolved part of missing sources in the global COS budget. [ABSTRACT FROM AUTHOR]

Black carbon (BC), an important component of atmospheric aerosol, plays a significant role in regional climate, hydrological cycle, variation of monsoon rainfall, and human health. The 40-year detailed atmospheric BC over China from 1981 to 2020 is systematically investigated through the MERRA-2 reanalysis dataset. MERRA-2 BC generally showed a good correlation (R = 0.68) compared with 673 monthly samples from ground-based observation at 35 stations around China. The overall annual average of MERRA-2 BC concentration over China is 1.15 μg/m3, with a fast growth rate during 1981–2007 and a relatively slow decrease after that. The winter season has the highest mean concentration of BC, followed by autumn and spring, whereas summer shows relatively weaker values. The order of annual average BC concentrations during 1981–2020 is Beijing-Tianjin-Hebei region (BTH, 4.02 μg/m3) > Sichuan Basin (SB, 3.94 μg/m3) > Yangtze River Delta (YRD, 2.68 μg/m3) > Pearl River Delta (PRD, 1.47 μg/m3). The monthly mean BC concentrations over the BTH, YRD, PRD and SB are estimated to be smallest 3.18 μg/m3 in May, 1.94 μg/m3 in August, 0.82 μg/m3 in July, 3.04 μg/m3 in June, respectively, whilst largest consistently in December with 5.09 μg/m3, 3.83 μg/m3, 2.12 μg/m3, and 5.41 μg/m3, respectively. Our study indicates the primary potential source areas for BC are concentrated in the research city and its surroundings. Beijing and Chengdu are more BC-polluted areas than Shanghai and Guangzhou. Long-distance, regional transfer from south BTH contributes importantly to BC pollution in Beijing under the influence of prevailing southerly winds. The geographical location of Chengdu causes the transport and accumulation of BC inside the SB. [ABSTRACT FROM AUTHOR]

The quantitative assessment of the spatial and temporal variability and drivers of fine particulate matter (PM2.5) fraction concentrations are important for pollution control and public health preservation in China. In this study, we investigated the spatial temporal variation of PM2.5 chemical component based on the PM2.5 chemical component datasets from 2000 to 2019 and revealed the driving forces of the differences in the spatial distribution using geodetector model (GD), multi-scale geographically weighted regression model (MGWR), and a two-step clustering approach. The results show that: the PM2.5 chemical fraction concentrations show a trend of first increasing (2000–2007) and then decreasing (2007–2019). From 2000 to 2019, the change rates of PM2.5, organic matter (OM), black carbon (BC), sulfates (SO2– 4), ammonium (NH+ 4), and nitrates (NO– 3) were −0.59, −0.23, −0.07, −0.15, −0.02, and 0.04μg/m3/yr in the entirety of China. The secondary aerosol (i.e., SO2− 4, NO− 3, and NH+ 4; SNA) had the highest fraction in PM2.5 concentrations (55.6–68.1% in different provinces), followed by OM and BC. Spatially, North, Central, and East China are the regions with the highest PM2.5 chemical component concentrations in China; meanwhile, they are also the regions with the most significant decrease in PM2.5 chemical fraction concentrations. The GD and MGWR model shows that among all variables, the number of enterprises, disposable income, private car ownership, and the share of secondary industry non-linearly enhance the differences in the spatial distribution of PM2.5 component concentrations. Electricity consumption has the strongest influence on NH+ 4 emissions in Northwest China and BC and OM emissions in Northeast China. [ABSTRACT FROM AUTHOR]

Atmospheric dry deposition of black carbon (BC) is a significant but poorly understood and inadequately described process in aerosol-climate models. The 40-year detailed dry deposition velocities of hydrophilic BC over China from 1981 to 2020 were systematically studied based on the MERRA-2 reanalysis data, which hopefully will be beneficial for its applications in atmospheric systems for climate and air quality. The average dry deposition flux of hydrophilic BC over China was 0.00059 ± 0.00014 μg m−2 s−1, while its dry deposition velocity was estimated to be 0.00051 ± 0.00004 m s−1. The monthly mean dry deposition fluxes of hydrophilic BC varied nearly 1.5 fold, ranging from the lowest 0.00046 ± 0.00011 μg m−2 s−1 in August to the highest 0.00068 ± 0.00019 μg m−2 s−1 in January. The spring season had the highest mean dry deposition flux of hydrophilic BC, followed by summer and winter, whereas autumn showed relatively weaker dry deposition flux. The mean dry deposition velocities of hydrophilic BC over the Beijing-Tianjin-Hebei region, Yangtze River Delta, Pearl River Delta and Tibet Plateau were estimated to be 0.00042 ± 0.00004, 0.00042 ± 0.00004, 0.00051 ± 0.00006 and 0.00078 ± 0.00005 m s−1, respectively. The monthly and seasonal patterns of dry deposition velocities of hydrophilic BC differed from each other in different regions, and high air temperature or surface wind speed seemed to fortify dry deposition velocities of hydrophilic BC. Our study pointed to high dry deposition flux of hydrophilic BC in the northern China Plain and Sichuan Basin but large dry deposition velocities in the Tibet Plateau region. [ABSTRACT FROM AUTHOR]

In this paper, we report the results obtained from one year of real-time measurement (i.e., from December 2019 to November 2020) of atmospheric black carbon (BC) under a rural environment in Qingdao of Northeastern China. The annual average concentration of BC was 1.92 ± 1.89 μg m−3. The highest average concentration of BC was observed in winter (3.65 ± 2.66 μg m−3), followed by fall (1.73 ± 1.33 μg m−3), spring (1.53 ± 1.33 μg m−3), and summer (0.83 ± 0.56 μg m−3). A clear weekend effect was observed in winter, which was characterized by higher BC concentration (4.60 ± 2.86 μg m−3) during the weekend rather than that (3.22 ± 2.45 μg m−3) during weekdays. The influence of meteorological parameters, including surface horizontal wind speed, boundary layer height (BLH), and precipitation, on BC, was investigated. In particular, such BLH influence presented evidently seasonal dependence, while there was no significant seasonality for horizontal wind speed. These may reflect different roles of atmospheric vertical dilution on affecting BC in different seasons. The △BC/△CO ratio decreased with the increase of precipitation, indicative of the influence of below-cloud wet removal of BC, especially during summertime where rainfall events more frequently occurred than any of other seasons. The bivariate-polar-plot analysis showed that the high BC concentrations were mainly associated with low wind speed in all seasons, highlighting an important BC source originated from local emissions. By using concentration-weighted trajectory analysis, it was found that regional transports, especially from northeastern in winter, could not be negligible for contributing to BC pollution in rural Qingdao. In the coronavirus disease 2019 (COVID−19) case analysis, we observed an obvious increase in the BC/NO2 ratio during the COVID-19 lockdown, supporting the significant non-traffic source sector (such as residential coal combustion) for BC in rural Qingdao. [ABSTRACT FROM AUTHOR]

Metabolic syndrome (MetS) is considered a main public health issue as it remarkably adds the risk of cardiovascular disease, leading to a heavy burden of disease. There is growing evidence linking fine particulate matter (PM 2.5) exposure to MetS. However, the influences of PM 2.5 constituents, especially in children and adolescents, remain unclear. Our study was according to a national analysis among Chinese children and adolescents to examine the associations between long-term exposure to PM 2.5 main constituents and MetS. A total of 10,066 children and adolescents aged 10–18 years were recruited in 7 provinces in China, with blood tests, health exams, and questionnaire surveys. We estimated long-term exposures to PM 2.5 mass and its five constituents, containing black carbon (BC), organic matter (OM), inorganic nitrate (NO 3 −), sulfate (SO 4 2−), and soil particles (SOIL) from multi-source data fusion models. Mixed-effects logistic regression models were used with the adjustment of a variety of covariates. In the surveyed populations, 2.9% were classified as MetS. From the single-pollutant models, we discovered that long-term exposures to PM 2.5 mass, BC, OM, NO 3 −, as well as SO 4 2−, were significantly associated with the prevalence of MetS, with odds ratios (ORs) per 1 μg/m3 that were 1.02 (95% confidence interval (CI): 1.01, 1.03) for PM 2.5 mass, 1.24 (95% CI: 1.14, 1.35) for BC, 1.07 (95% CI: 1.04, 1.11) for OM, 1.09 (95% CI: 1.04, 1.13) for NO 3 −, and 1.14 (95% CI:1.04, 1.24) for SO 4 2−. The influence of BC on the prevalence of MetS was robust in both the multi-pollutant model and the PM 2.5 -constituent joint model. The paper indicates long-term exposure to PM 2.5 mass and specific PM 2.5 constituents, particularly for BC, was significantly associated with a higher MetS prevalence among children and adolescents in China. Our results highlight the significance of establishing further regulations on PM 2.5 constituents. • 10,066 children and adolescents from 7 province with blood tests were involved. • Long-term exposure to PM 2.5 mass was significantly associated with the childhood MetS. • Black carbon exposure has a robust positive association with childhood MetS. [ABSTRACT FROM AUTHOR]

Aerosols are a significant source of dissolved black carbon (DBC) in the ocean. However, how anthropogenic activities, including fossil fuel (FF) burning and human‐initiated biomass burning (BB), would affect the seasonal variations in the concentration and condensation degree of aerosol DBC was not well constrained. To fill this knowledge gap, we collected 33 aerosol samples from December 2018 to September 2019 at a southeast coastal site in China. Concentrations of DBC, water‐soluble organic carbon (WSOC), and elemental carbon (EC) were determined, and air quality data were collected. DBC concentration was 0.02–0.23 μgC m−3, with significantly higher values in spring and winter, and was affected by sources, rainfall frequency, and secondary processes. The source of DBC, as indicated by DBC/WSOC (range: 0.009–0.045) and DBC/EC (range: 0.007–0.065), was dominated by FF burning. Furthermore, the significantly higher DBC/WSOC value in late April to July indicated enhanced contribution from BB that was mainly associated with airmass transported from Southeast Asia (SEA). We further estimated that ∼30% of aerosol DBC was from BB from May to July. The condensation degree of DBC was variable, with significantly higher values in winter and spring, which might be associated with prolonged photo‐dissolution. Significant correlations were also observed between DBC and PM10 and PM2.5, which might be utilized to estimate DBC deposition flux, albeit requiring more studies. Our study emphasized the influence of human activities (including BB activities) on atmospheric DBC deposition, which might affect the regional and even global DBC pools. Plain Language Summary: As a significant source of dissolved black carbon (DBC) to the ocean, the sources and temporal variation in its concentration and condensation degree were not well constrained. In this study, we collected 33 aerosol samples at a coastal site in China. We determined concentrations of DBC, water‐soluble organic carbon, and elemental carbon (EC). Air quality and meteorological parameters were also collected. Our results showed that DBC at this coastal site was primarily derived from fossil fuel (FF) burning, with enhanced contribution from biomass burning that was brought by East Asian Monsoon. In addition, DBC concentration varied significantly among seasons, and was influenced by changes in sources, rainfall frequency as well as secondary processes. Moreover, we found that DBC concentration was significantly positively correlated with PM10 and PM2.5, which provided a potential way to predict DBC depositional flux in other regions that was mainly affected by FF burning. Our study indicated that human activities (FF burning and human‐initiated biomass burning) could have significant impact on atmospheric DBC deposition, which might also affect the oceanic DBC pool in the future. Key Points: The seasonal variation in the dissolved black carbon (DBC) concentration was affected by sources, rainfall frequency, and secondary processes in XiamenThe sources of DBC in the aerosols mainly originated from the burning of fossil fuelThe DBC concentration was highly significantly correlated with PM10 and PM2.5, which could be a simple way to estimate DBC deposition flux [ABSTRACT FROM AUTHOR]

The wet deposition flux of black carbon (BC) over the Sichuan Basin is studied on the basis of the MERRA-2 data from 1981 to 2020, aiming at investigating high BC wet deposition flux in China in terms of long-term spatial-temporal trends and influences of BC column mass density and precipitation. In China, the largest BC wet deposition flux with a regionally-averaged value of 1.00 × 10−2 μg m−2 s−1 over the Sichuan Basin is observed, especially in the western and southern regions of the Basin with values as high as 2.20 × 10−2 μg m−2 s−1. The seasonality of BC wet deposition flux over the Sichuan Basin depicts maximum levels in autumn, moderate levels in spring and winter, and minimum levels in summer. The monthly mean BC wet deposition flux varies almost twofold, ranging from the lowest average value of 8.05 × 10−3 μg m−2 s−1 in July to the highest 1.28 × 10−2 μg m−2 s−1 in October. This study suggests that BC column mass density and precipitation are two significant factors affecting high BC wet deposition flux, whereas BC wet deposition flux is more related to BC column mass density than to precipitation over the Sichuan Basin. [ABSTRACT FROM AUTHOR]

The painted sculptures in ancient Chinese folk temples are important traditional folk painting art forms, and it is of great significance for painted sculptures conservation to study the materials and techniques employed in their production. In this study, firstly, the samples from eight different colored painted sculptures were collected at Fushan Temple (1595–1882 AD) in Heyang County, Shaanxi Province, China. Secondly, the surface morphology and cross-sectional structure of the painted sculptures were investigated using optical microscopy and scanning electron microscopy (SEM). In addition, qualitative and semi-quantitative studies of the elemental and physical phase compositions of the materials used in the manufacture of the painted sculptures were conducted by X-ray diffraction (XRD), Raman spectroscopy, and energy-dispersive X-ray spectroscopy (EDS). The results showed that the painted sculpture samples from Fushan Temple comprised a pigment layer, white powder layer, fine clay layer, and coarse clay layer from the outside to the inside. The white powder layer was made of chalk, with functions in color development and leveling. The fine clay layer comprised quartz and other sand particles with small grain sizes. The coarse clay layer comprised feldspar and cotton silk, with larger grain size. In addition, the pigments used in the painted sculptures were chrome red, lapis lazuli, phthalocyanine green, earth green, amorphous carbon black, iron oxide red, and pyrite. The green pigment was earth green in the early stages but it was later repainted with phthalocyanine green mixed with some lapis lazuli pigments for toning. In addition, the dark green and brown pigments comprised mixtures of amorphous carbon black and phthalocyanine green, and amorphous carbon black and iron oxide red, respectively. [ABSTRACT FROM AUTHOR]

Biomass burning organic aerosol (BBOA) impacts significantly on climate directly through scattering and absorbing solar radiation and indirectly through acting as cloud condensation nuclei. However, fundamental parameters in the simulation of BBOA radiative effects and cloud activities such as size distribution and refractive index remain poorly parameterized in models. In this study, biomass burning events with high combustion efficiency characterized by a high black carbon (BC) to BBOA ratio (0.22 on average) were frequently observed during autumn in the Pearl River Delta region, China. An improved absorption Ångström exponent (AAE) ratio method considering both variations and spectral dependence of black carbon AAE was proposed to differentiate brown carbon (BrC) absorptions from total aerosol absorptions. BBOA size distributions, mass scattering and absorption efficiency were retrieved based on the changes in aerosol number size distribution, scattering coefficients and derived BrC absorptions that occurred with BBOA spikes. Geometric mean diameter of BBOA volume size distribution Dgv depended largely on combustion conditions, ranging from 245 to 505 nm, and a linear relationship between Dgv and ΔBC/ΔBBOA ​​​​​​​ was achieved. The retrieved real part of the BBOA refractive index ranges from 1.47 to 1.64, with evidence showing that its variations might depend largely on combustion efficiency, which is rarely investigated in existing literature but which however requires further comprehensive investigations. Retrieved imaginary parts of BBOA refractive index (mi,BBOA) correlated highly with ΔBC/ΔBBOA (R>0.88) but differ a lot from previous parameterization schemes. The reason behind the inconsistency might be that single formula parameterizations of mi,BBOA over the whole BC/BBOA range were used in previous studies which might deviate substantially for specific BC/BBOA ranges. Thus, a new scheme that parameterizes wavelength-dependent mi,BBOA was presented, which filled the gap for field-based BBOA absorptivity parameterizations of ​​​​​​​BC/BBOA >0.1. These findings have significant implications for simulating BBOA climate effects and suggest that linking both BBOA refractive index and BBOA volume size distributions to BC content might be a feasible and a good choice for climate models. [ABSTRACT FROM AUTHOR]

Black carbon (BC) may have more adverse effects on human health than other constituents of PM2.5. The daily mean concentrations of BC in China are much higher than those in developed countries and are estimated to account for more than a quarter of global anthropogenic BC emissions. However, reports on the health effects of BC in China have been limited. Thus, a time-stratified case-crossover study was conducted to evaluate the impacts of BC on daily mortality risk in nine Chinese megacities from 2008–2016. Our results show that for all-cause mortality, when compared to the interquartile range (IQR) of BC concentration increased, odds ratios (ORs) were in the range of 1.01–1.06 (95% CIs: 0.99–1.10). For cardiovascular mortality, ORs were in the range of 1.02–1.07 (95% CIs: 1.003–1.12), and for respiratory mortality, ORs were in the range of 1.01–1.15 (95% CIs: 1.00–1.18). The effects of BC in the nine cities were robust after adjusting for PM2.5, or even became more prominent. Furthermore, BC had stronger effects in spring and winter in northern cities, whereas in mid-latitude cities, BC had stronger effects in the warm seasons. In southern cities, BC had stronger effects in the cool and dry seasons. Our findings support an association between residential exposure to BC and mortality and thus provide further evidence that BC negatively impacts human health and is helpful for decision-making. [ABSTRACT FROM AUTHOR]

Large uncertainties remain when estimating the radiative forcing by black carbon (BC) because the corresponding microphysical properties have not been well addressed. In this study, the BC size distributions were studied based on three different field campaigns at an urban site, a suburban site, and a background site in China using a single particle soot photometer (SP2) in tandem with a differential mobility diameter. Measurement results indicate that the BC particles were composed of either thinly or thickly coated aerosols. The mean number fractions of the thinly coated BC aerosols were 51 %, 67 %, and 21 % for the urban, suburban, and background sites, respectively. The corresponding thickly coated (thinly coated) core mass median diameters were 187 (154), 182 (146), and 238 (163) nm, respectively. The mean diameter of the thickly coated BC-containing aerosols was larger than that of the thinly coated BC-containing aerosols, while the mean BC core diameter of the thickly coated BC-containing aerosols was smaller than that of the thinly coated BC-containing aerosols. About 10 % of the BC-containing aerosols with the BC core are attached to the other non-BC components, which were mainly generated by coagulation between the BC and non-BC components. The measurement results in our study can be further used in modeling studies to help with constraining the uncertainties of the BC radiative effects. [ABSTRACT FROM AUTHOR]

Coal combustion for winter heating is a major source of heavy atmospheric pollution in China, while its impacts on black carbon (BC) are not yet clear. A dual-spot Aethalometer was selected to monitor the atmospheric BC concentration in Zhengzhou, China, during the heating season, which is from 15 November through 15 March of the following year, and the non-heating season (days other than heating season). The characteristics and sources of BC were analyzed, and a concentration weight trajectory (CWT) analysis was conducted. The results showed that the BC concentrations in the heating season were generally higher than those in the non-heating season. The diurnal variation in BC concentrations during heating season was bimodal, and that during the non-heating season was unimodal. The α-values in the heating and non-heating seasons indicated that combustion of coal and biomass and vehicle emissions were the major BC sources for the heating season and non-heating season, respectively. BC concentrations were positively correlated with PM2.5, PM10, CO, and NOX. There was a strong negative correlation between wind speed and BC concentrations, and that for relative humidity was the opposite. BC concentration during heating season was mainly influenced by the northwestern areas of China and the eastern part of Henan, and that in the non-heating season was mainly from the northeastern areas of China and southern Henan. [ABSTRACT FROM AUTHOR]

Black carbon (BC) is one of the dominant absorbing aerosol species in the atmosphere. It normally has complex fractal-like structures due to the aggregation process during combustion. A wide range of aerosol–radiation interactions (ARIs) of BC have been reported throughout experimental and modeling studies. One reason for the large discrepancies among multiple studies is the application of the oversimplified spherical morphology for BC in ARI estimates. In current climate models, the Mie theory is commonly used to calculate the optical properties of spherical BC aerosols. Here, we employ a regional chemical transport model coupled with a radiative transfer code that utilizes the non-spherical BC optical simulations to re-evaluate the effects of particles' morphologies on BC shortwave ARI, and the wavelength range of 0.3–4.0 µ m was considered. Anthropogenic activities and wildfires are two major sources of BC emissions. Therefore, we choose the typical polluted area in eastern China, which is dominated by anthropogenic emissions, and the fire region in the northwest US, which is dominated by fire emissions in this study. A 1-month simulation in eastern China and a 7 d simulation in the fire region in the northwest US were performed. The fractal BC model generally presents a larger clear-sky ARI compared to the spherical BC model. Assuming BC particles are externally mixed with other aerosols, the relative differences in the time-averaged clear-sky ARI between the fractal model with a fractal dimension (Df) of 1.8 and the spherical model are 12.1 %–20.6 % and 10.5 %–14.9 % for typical polluted urban cities in China and fire sites in the northwest US, respectively. Furthermore, the regional-mean clear-sky ARI is also significantly affected by the BC morphology, and relative differences of 17.1 % and 38.7 % between the fractal model with a Df of 1.8 and the spherical model were observed in eastern China and the northwest US, respectively. However, the existence of clouds would weaken the BC morphological effects. The time-averaged all-sky ARI relative differences between the fractal model with a Df of 1.8 and the spherical model are 4.9 %–6.4 % and 9.0 %–11.3 % in typical urban polluted cities and typical fire sites, respectively. Besides, for the regional-mean all-sky ARI, the relative differences between the fractal model and the spherical model are less than 7.3 % and 16.8 % in the polluted urban area in China and the fire region in the US, respectively. The results imply that current climate modeling may significantly underestimate the BC ARI uncertainties as the morphological effects on BC ARI are ignored in most climate models. [ABSTRACT FROM AUTHOR]

China has been implementing a sequence of policies for clean air since the year 2013, and the aerosol pollution has been substantially improved, but ozone (O 3)-related issues arose. Here, fast climate responses to emission reductions in aerosol and O 3 precursors over China during 2013–2017 are investigated using the Community Earth System Model version 2 (CESM2). The overall decreases in aerosols produced an anomalous warming of 0.09 ± 0.10 ∘ C in eastern China (22–40 ∘ N, 110–122.5 ∘ E), which is further intensified by the increase in O 3 in the lower troposphere, resulting in an enhanced warming of 0.16 ± 0.15 ∘ C in eastern China. Reductions in industrial emissions contributed the most to the aerosol-induced warming, while emission reductions from residential sector induced a cooling effect due to a substantial decrease in light-absorbing black carbon aerosols. This implies that switching the residential sector to cleaner energy is more effective to achieve climate and health benefits in China. [ABSTRACT FROM AUTHOR]

Estimates of the effective radiative forcing from aerosol‐radiation interaction (ERFari) of anthropogenic Black Carbon (BC) have been disputable and require better constraints. Here we find a substantial decline in atmospheric absorption of −5.79Wm−2decade−1 over eastern central China (ECC) responding to recent anthropogenic BC emission reductions. By combining the observational finding with advances from Coupled Model Intercomparison Project phase6 (CMIP6), we identify an emergent constraint on the ERFari of anthropogenic BC. We show that across CMIP6 models the simulated trends correlate well with simulated annual mean shortwave atmospheric absorption by anthropogenic BC over China. Making use of this emergent relationship allows us to constrain the aerosol absorption optical depth of anthropogenic BC and further provide a constrained range of 2.4–3.0 Wm−2 for its top‐of‐atmosphere ERFari over China, higher than existing estimates. Our work supports a strong warming effect of BC over China, and highlights the need to improve BC simulations over source regions. Plain Language Summary: Black Carbon (BC) widely affects the Earth system as a warming agent. However, estimates of the effective radiative forcing from aerosol‐radiation interaction (ERFari) by anthropogenic BC remain disputable with recent studies arguing for a downward revision, and therefore require better constraints. Here we find that atmospheric absorption declines evidently over eastern central China since 2005 due to reduced anthropogenic BC emissions. When analyzing results from the latest Coupled Model Intercomparison Project phase 6 (CMIP6) models, we further find that though the majority of models underestimate the observed trends, the simulated trends across CMIP6 models correlate well with simulated annual mean shortwave atmospheric absorption by anthropogenic BC over China. Combining this relationship with the observational range of the trends allows us to identify an emergent constraint on the aerosol absorption optical depth of anthropogenic BC and further provide an observationally constrained range of 2.4–3.0Wm−2 for its top‐of‐atmosphere ERFari. This estimate is substantially higher than all existing estimates, providing independent evidence to support a strong warming effect of BC over China. Our work also points out a common low bias of current global models in simulating BC over China, and highlights the need to improve BC simulations over source regions. Key Points: Atmospheric absorption declines substantially over eastern central China in response to recent reductions of anthropogenic Black Carbon (BC) emissionsThe observational finding combined with the latest Coupled Model Intercomparison Project phase 6 (CMIP6) models enable an emergent constraint on the anthropogenic BC forcing over ChinaThe constrained effective radiative forcing from aerosol‐radiation interaction of anthropogenic BC is higher than existing estimates [ABSTRACT FROM AUTHOR]

Black carbon (BC) aerosol measured at the WMO/GAW Station Mt. Waliguan from 1994 to 2017 has been analyzed. The 24 years long-term results showed that the average annual concentration ranges from 1.9 × 102 ng m−3 to 5.1 × 102 ng m−3 from 2001 to 2012, with a growth rate of 29%. However, the concentration of black carbon decreased from 2012 to 2016, with a decline rate of 64%. The monthly average concentration over the 24 years ranged from 90 ng m−3 to 7.0 × 102 ng m−3, with the peak value occurring in April and the lowest value occurring in November. The diurnal variation presented two peak types in different seasons, the first occurred at 20:00 a.m.~23:00 a.m. in the evening, and another around 06:00 a.m.~08:00 a.m. In addition, we found that the transport of black carbon aerosol is closely related to wind transport. The annual maximum black carbon concentration occurred in the east-northeast (ENE) wind direction, with a value of 4.6 × 102 ng m−3, and the second peak value occurred in the E wind direction, with a value of 3.9 × 102 ng m−3. The black carbon concentration of Waliguan was relatively high under the three wind directions of Northeast (NE), ENE, and east (E), which represented the influence of black carbon aerosol generated by human activities located on the east of the station. The 96-h backward trajectory analysis indicated that the sources in the southwest direction made a greater contribution to the black carbon concentration. the pollutants mainly came from the northwest and west sides according to the analysis of potential sources using the CWT approach. The study of black carbon evolution and contribution area is of great significance to further improve the capacity and level of global climate change research and prediction. [ABSTRACT FROM AUTHOR]

Rapid urbanization causes the accumulation of large amounts of pollutants, including heavy metals, organic pollutants, and black carbon (BC). BC is the carbonaceous residue generated from the incomplete combustion of fossil fuels and biomass. It plays an important role on the migration of heavy metals and organic pollutants, as well as soil carbon sequestration. BC accumulation due to human activities greatly affects the global carbon budget, helps to drive climate change, and damages human health. To date, few studies have examined how the intensity of urbanization affects the distribution of BC in soils in urban areas. Therefore, the objective of this study is to determine the effects of urbanization intensity on the spatial distribution and content of BC in urban surface soil. We collected samples from 55 sites in South China and used a multi-scale geographical regression model to evaluate the impact of the interference intensity of urbanization on the amount and distribution of BC. Our results showed that the BC content was significantly higher in urban areas (9.74 ± 1.18 g kg−1) than in rural areas (2.94 ± 0.89 g kg−1) and that several urban parks with a higher interference intensity were hotspots of BC accumulation, suggesting that urbanization promoted BC accumulation. Our model revealed that road density was significantly and positively correlated with BC accumulation. Because there are more cars driving in areas with high road density, vehicle emissions may be one of the causes of BC accumulation. Our results also indicated that the impact of urbanization intensity on the BC distribution was sensitive to sampling density. [ABSTRACT FROM AUTHOR]

Airborne black carbon is a strong warming component of the atmosphere. Therefore, curbing black carbon emissions should slow down global warming. The 2019 coronavirus pandemic (COVID-19) is a unique opportunity for studying the response of black carbon to the varied human activities, in particular due to lockdown policies. Actually, there is few knowledge on the variations of black carbon in China during lockdowns. Here, we studied the concentrations of particulate matter (PM2.5) and black carbon before, during, and after the lockdown in nine sites of the Yangtze River Delta in Eastern China. Results show 40–60% reduction of PM2.5 and 40–50% reduction of black carbon during the lockdown. The classical bimodal peaks of black carbon in the morning and evening rush hours were highly weakened, indicating the substantial decrease of traffic activities. Contributions from fossil fuels combustion to black carbon decreased about 5–10% during the lockdown. Spatial correlation analysis indicated the clustering of the multi-site black carbon concentrations in the Yangtze River Delta during the lockdown. Overall, control of emissions from traffic and industrial activities should be efficient to curb black carbon levels in the frame of a 'green public transit system' for mega-city clusters such as the Yangtze River Delta. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports findings of a recent field study that characterized the on-road emissions of individual diesel vehicles in and around Beijing, China during November and December of 2009. We successfully sampled 230 individual trucks on 4 major expressways around the city as well as 57 individual buses in the city using refined mobile chasing techniques and fast response instruments. Emission factors (EF) for carbon monoxide (CO), black carbon (BC) and particulate matter with diameters less than 0.5 μm (PM0.5) are derived from the measurements, which are consistent with the results from laboratory dynamometer tests. The PM0.5 number emission factor distributions demonstrate consistent bimodal modes with peaks around 10 nm and 80 nm, while the mass emission factor distributions demonstrate a unimodal maximum around 110 nm for a majority of the trucks. The BC emissions are shown to be highly correlated with the mass emission of particles with 100–250 nm diameters, which are in good agreement with the results from previous studies. A number of important policy implications are discussed based on the results from this study. First, we identified “heavy emitters” in the on-road fleet we encountered, finding that 5% of diesel trucks in this sample are responsible for 50% of total BC emissions, and 20% of the trucks are responsible for 50% CO and PM0.5 number emissions, 60% PM0.5 mass emissions and over 70% of BC emissions. This suggests that emissions control programs should include identifying and removing heavy emitters from the road or improving their emissions. Second, the BC and PM0.5 number emission factors of trucks registered in regions outside Beijing are significantly higher than those of Beijing-registered trucks, suggesting that improving engine and fuel standards in Beijing alone is not sufficient in reducing the traffic-related air pollution in Beijing. Third, the significantly lower emissions from Euro IV and CNG buses compared to the Euro II and Euro III buses support that introducing clean-burning buses is an effective way to reduce the overall vehicle emissions for the pollutants studied. Fourth, our refined chasing method demonstrates a cost-effective approach to characterize the emissions from a large number of on-road diesel vehicles. Further studies with large sample sizes are critical to constructing more accurate mobile emission inventories to represent the on-road vehicle population. [Copyright &y& Elsevier]

Abstract: The aggressive traffic interventions and emission control measures implemented to improve air quality during the 2008 Beijing Olympic Games created a valuable case study to evaluate the effectiveness of these measures on mitigating air pollution and protecting public health. In this paper, we report the results from our field campaign in summer 2008 on the on-road emission factors of carbon monoxide, black carbon (BC) and ultrafine particles (UFP) as well as the ambient BC concentrations. The fleet average emission factors for light-duty gasoline vehicles (LDGV) showed considerable reduction in the Olympic year (2008) compared to the pre-Olympic year (2007). Our measurement of Black Carbon (BC), a primary pollutant, at different elevations at the ambient site suggests consistent decrease in BC concentrations as the height increased near the ground level, which indicates that the nearby ground level sources, probably dominated by traffic, contributed to a large portion of BC concentrations in the lower atmospheric layer in Beijing during summertime. These observations indicate that people living in near ground levels experience higher exposures than those living in higher floors in Beijing. The BC diurnal patterns on days when traffic control were in place during the Olympic Games were compared to those on non-traffic-control days in both 2007 and in 2008. These patterns strongly suggest that diesel trucks are a major source of summertime BC in Beijing. The median BC concentration on Olympic days was 3.7 μg m−3, which was dramatically lower than the value on non-traffic-control days, indicating the effectiveness of traffic control regulations in BC reduction in Beijing. [Copyright &y& Elsevier]

Polycyclic aromatic hydrocarbons (PAHs) are a kind of organic pollutants with carcinogenic, teratogenic, and mutagenic effects. This study aims to assess the effects of changes in China's socio-economic indicators represented by energy consumption and number of motor vehicles, on PAHs and black carbon (BC) deposition. For this, a 50-cm peat core from Dajiuhu peatland, Central China, was collected and divided into 50 subsamples to establish a sedimentary record of about 200 years with radioactive 210Pb. The Σ16PAH concentration ranged from 212.67 to 830.10 ng·g−1, mainly composed of 2- and 3-ring PAHs, and BC ranged from 7.89 to 36.48%. The deposition characteristics of BC first increased and then decreased from the core bottom to the top. The predominant of the carcinogenic PAHs (C-PAHs) was Dibenzo[a,h]anthracene (DBA) before 1949, and then changed to Benzo[b]fluoranthene (BbF). Ratio of Fla/Pyr, (3+4)-ring/(5+6)-ring PAHs, and BaA/(BaA+Chr), IcdP/(IcdP+BghiP) suggested that long-range atmospheric transmission (LRAT) and pyrogenic were the main PAHs sources, but that local PAH emission contribution gradually increased since 1990, and mixed (petroleum and combustion) sources were the dominant since 2000. The high concentration of Phenanthrene (Phe) and Naphthalene (Nap) were likely from plant product. Furthermore, increased concentrations of 4-, 5-, and 6-ring PAHs showed significant correlations with increased coal and petroleum consumption and the number of motor vehicles, respectively, and this influence has strengthened after 2000. These were caused by rapid urbanization and industrialization following the implementation of the reform and opening up policy in 1978, and a new round of urbanization after 2000. [ABSTRACT FROM AUTHOR]

Wildfire activity is an important activity in evolution of vegetation and carbon cycling. Whether wet weather will suppress wildfire or promote them by increasing fuel reserves during the Holocene is not clear. We obtained a record of black carbon from a sediment core spanning the last 14.8 kyr from Gonghai Lake, in North China. There is a close relationship between the timing of wildfire activity and vegetation development driven by the East Asian summer monsoon intensity. On a millennial timescales, wet climatic conditions provide a sufficient biofuels reserve, in the same period wildfire increase; thus, the regional potential biofuels reserve is shown to be an important controlling of regional wildfire activity in the monsoon region of China, under natural conditions. We infer that with the strengthening of Asian summer monsoon caused by global warming, the wildfire carbon emission in Asian monsoon region may increase in the future. Plain Language Summary: Much attention has been paid to the response of wildfire activity to climate change. Understanding the past history of wildfires and their triggering factors may help us to mitigate the effects of future wildfires. Our study of the black carbon record of the sediments from an alpine lake (Gonghai Lake) in North China indicates that the level of biofuels (mainly woody vegetation) was the main control on the intensity of wildfire on a millennial timescales over the past ∼14,800 yr. When the climate was wetter, more biofuels were available as a result of increased biomass storage, wildfires were more intense with a relatively stable ignition probability. So, climate trends that favor vegetation development will lead to a higher intensity of wildfire and carbon emission in the Asian monsoon region in the future, with the strengthening of Asian summer monsoon caused by global warming. Key Points: The variation of wildfire and summer monsoon is consistent on the millennial scale, wet climate drives wildfire enhancingBiofuels reserve has controlled wildfire for the Holocene in Asian summer monsoon regionStronger monsoons caused by global warming would increase wildfire carbon emission [ABSTRACT FROM AUTHOR]

Black carbon (BC) is the most potent light-absorbing component of particulate matter and can have a significant warming impact. On-road vehicles are a major source of BC and a significant contributor to global warming. This paper establishes an updated inventory to quantify the mitigation potential of efforts to control BC emissions from on-road transportation in China. The total emissions of BC from on-road vehicles in China were 152.1 thousand tons in 2017. Heavy-duty diesel fleets accounted for a large percentage of emissions, whereas light-duty gasoline fleets presented a gradually increasing trend of emissions. Historically, comprehensive control policies for on-road vehicle emissions have achieved substantial BC reductions, with a 45% decrease in 2017 compared to 2000. With the implementation of stringent control policies and the development of advanced control technologies, BC emissions from the on-road sector may have a greater reduction potential in the future. By 2035, three various future scenarios representing different stringency levels of emission controls will reduce BC emissions by 58%, 90%, and 93% relative to 2017. The major benefits in reducing BC emissions result from more stringent emission standards and the accelerated retirement of older heavy-duty diesel vehicles. The shorter lifetime of BC than that of CO 2 implies that the mitigation of BC emissions would offer an important opportunity to contribute to alleviating global warming in the short term. Our assessment reveals that in 2035, the most stringent scenario, Scenario PC3 , could deliver a CO 2 -equivalent emission reduction on a 20-year scale of 234.2 (GWP 20-yr) million tons compared with the NAP Scenario, which is equivalent to reducing the oil consumption in China's transportation sector by nearly 20% from a climate impact perspective. [Display omitted] • The historical and future BC emissions from on-road vehicles in China are estimated. • Comprehensive control policies have achieved a substantial BC reduction with a 45% decrease. • BC emissions from the on-road sector suggest a greater reduction potential in the future. • The most stringent Scenario can deliver a CO 2 -equivalent reduction of 234.2 million tons (GWP 20-yr) in 2035. • The BC emission mitigation potential could be equivalent to ∼20% of the climate benefits from fuel savings. [ABSTRACT FROM AUTHOR]

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When black carbon (BC) is mixed internally with other atmospheric particles, the BC light absorption effect is enhanced. This study explicitly resolved the optical properties of coated BC in snow based on the core / shell Mie theory and the Snow, Ice, and Aerosol Radiative (SNICAR) model. Our results indicated that the BC coating effect enhances the reduction in snow albedo by a factor ranging from 1.1–1.8 for a nonabsorbing shell and 1.1–1.3 for an absorbing shell, depending on the BC concentration, snow grain radius, and core / shell ratio. We developed parameterizations of the BC coating effect for application to climate models, which provides a convenient way to accurately estimate the climate impact of BC in snow. Finally, based on a comprehensive set of in situ measurements across the Northern Hemisphere, we determined that the contribution of the BC coating effect to snow light absorption exceeds that of dust over northern China. Notably, high enhancements of snow albedo reduction due to the BC coating effect were found in the Arctic and Tibetan Plateau, suggesting a greater contribution of BC to the retreat of Arctic sea ice and Tibetan glaciers. [ABSTRACT FROM AUTHOR]

Light absorption enhancement of black carbon due to the aerosol mixing states is an important parameterization for climate modeling, while emission source contributions to the enhancement factor are unclear. An intensive campaign was conducted simultaneously at a China coastal site (Qingdao city) and maritime sites (South Yellow Sea, SYS) in August and Nov to Dec 2018. The absorption enhancement (EMAC) of the black carbon was calculated using a two-step solvent dissolution protocol and found 1.96 ± 0.68, 1.64 ± 0.38, and 2.40 ± 0.76 for Qingdao summer (QS), Qingdao autumn (QA), and SYS, respectively. Positive matrix factorization (PMF) model identified six sources of PM2.5 and EMAC, which were secondary aerosol (with contribution 27.9% and 29.2%), coal combustion (24.9% and 20.2%), industrial emissions (15.2% and 25.4%), sea salt (6.9% and 9.6%), vehicle emissions (12.1% and 10.9%), and soil dust (13.0% and 4.7%), respectively. These sources increased the absorption of black carbon by a factor of 1.25 ± 0.11 (secondary aerosol), 1.21 ± 0.20 (industrial emissions), 1.17 ± 0.08 (coal combustion), 1.09 ± 0.07 (vehicle emissions), 1.08 ± 0.17 (sea salt), and 1.04 ± 0.10 (soil dust). Based on the correlation between PM and EMAC source contributions, we estimated that secondary aerosols, industrial emissions, and coal combustion contributed to 74.8% of absorption enhancement at a regional scale in China. The source apportionment for EMAC offers a new diagnosis for each source regarding aerosol forcing simulation which inputs from the individual emission sector. [ABSTRACT FROM AUTHOR]

Urbanization in China has dramatically increased from 39.10 in 2002 to 58.52% in 2017. Studies have discussed the impacts of urbanization and its corresponding changes in consumption patterns on carbon dioxide emissions; however, little is known about their impacts on black carbon (BC). Therefore, we collected data on the BC emissions of various sectors to calculate the consumption-based BC emissions in China, and we used an input–output analysis (IOA) and structural decomposition analysis (SDA) to explore the impacts of urbanization and changes in consumption patterns on BC emissions from 2002 to 2017, focusing on sectoral BC emissions. The total BC emissions of various sectors first increased and then decreased. BC emissions increased from 1083.47 in 2002 to 2550.83 Gg in 2012. They were then reduced to 2478.63 Gg in 2017. Additionally, with the rise in the urbanization rate, household consumption BC emissions increased from 446.18 in 2002 to 1080.12 Gg in 2017. Urban consumption, rural consumption, and BC emission intensity were the three main contributing factors to household consumption BC emission changes. Transport, storage, postal, and telecommunications services (TSP); farming, forestry, animal husbandry, and fishery (FFA); and residential and other industries (RES) contributed the most to the urbanization-related BC emission increase. In particular, the TSP sector contributed the most to the BC emission increase because of the increasing TSP needs related to urbanization. Therefore, it is necessary to formulate mitigation policies for the TSP sector. [ABSTRACT FROM AUTHOR]

Two new species, Hyphoderma fissuratum and H. mopanshanense spp. nov., are proposed based on morphological and molecular evidences. Hyphoderma fissuratum is characterized by resupinate basidiomata with cracking hymenial surface, a monomitic hyphal system with generative hyphae bearing clamp connections, IKI-, CB-, and cylindrical, colorless, thin-walled, smooth basidiospores measuring (8.5-10.3 × 3-4 µm). Hyphoderma mopanshanense is characterized by an annual growth habit, slight gray to cream hymenial surface, and fusiform, thick-walled cystidia apically encrusted with crystal. Sequences of ITS and LSU nrRNA gene regions of the studied samples were generated, and phylogenetic analyses were performed with maximum likelihood, maximum parsimony and Bayesian inference methods. These phylogenetic analyses based on molecular data of ITS and nLSU sequences showed that two Hyphoderma new species formed a well supported monophyletic lineage distinct from other related species and then H. fissuratum grouped with H. medioburiense and H. roseocremeum. Hyphoderma mopanshanense grouped with H. setigerum. [ABSTRACT FROM AUTHOR]

Black carbon (BC) forms an important component of particulate matter globally, due to its impact on climate, the environment and human health. Identifying and quantifying its emission sources are critical for effective policymaking and achieving the desired reduction in air pollution. In this study, we present the first direct measurements of urban BC fluxes using eddy covariance. The measurements were made over Beijing within the UK-China Air Pollution and Human Health (APHH) winter 2016 and summer 2017 campaigns. In both seasons, the mean measured BC mass (winter: 5.49 ng m -2 s -1 , summer: 6.10 ng m -2 s -1) and number fluxes (winter: 261.25 particles cm -2 s -1 , summer: 334.37 particles cm -2 s -1) were similar. Traffic was determined to be the dominant source of the BC fluxes measured during both seasons. The total BC emissions within the 2013 Multi-resolution Emission Inventory for China (MEIC) are on average too high compared to measured fluxes by a factor of 58.8 (winter) and 47.2 (summer). Only a comparison with the MEIC transport sector shows that emissions are also larger (factor of 37.5 in winter and 37.7 in summer) than the measured flux. Emission ratios of BC / NO x and BC / CO are comparable to vehicular emission control standards implemented in January 2017 for gasoline (China 5) and diesel (China V) engines, indicating a reduction of BC emissions within central Beijing, and extending this to a larger area would further reduce total BC concentrations. [ABSTRACT FROM AUTHOR]

Black carbon (BC) is the most important light-absorbing aerosol in the atmosphere. However, sources of atmospheric BC aerosols are largely uncertain, making it difficult to assess its influence on radiative forcing and climate change. In this study, year-round light-absorption observations were conducted during 2014 using an aethalometer in Xiamen, a coastal city in Southeast China. Source apportionment of BC was performed and temporal variations in BC sources were characterized based on both light absorption measurements and a source-oriented air quality model. The annual average concentrations of BC from fossil fuel (BC ff) and biomass burning (BC bb) by the aethalometer method were 2932 ± 1444 ng m -3 and 1340 ± 542 ng m -3 , contributing 66.7 % and 33.3 % to total BC, respectively. A sensitivity analysis was performed with different absorption Ångström exponent (AAE) values of fossil fuel combustion (αff) and biomass burning (αbb), suggesting that the aethalometer method was more sensitive to changes in αbb than αff. BC bb contribution exhibited a clear diurnal cycle, with the highest level (37.9 %) in the evening rush hour and a seasonal pattern with the maximum (39.9 %) in winter. Conditional probability function (CPF) analysis revealed the large biomass-burning contributions were accompanied by east-northeasterly and northerly winds. Backward trajectory indicated that air masses from North and East–Central China were associated with larger biomass-burning contributions. Potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) suggested that North and East–Central China and Southeast Asia were potential sources of both BC ff and BC bb. The source-oriented modeling results showed that transportation, residential and open biomass burning accounting for 45.3 %, 30.1 % and 17.6 % were the major BC sources. Among the three fuel catalogs, liquid fossil fuel (46.5 %) was the largest source, followed by biomass burning (32.6 %) and coal combustion (20.9 %). Source contributions of fossil fuel combustion and biomass burning identified by the source-oriented model were 67.4 % and 32.6 %, respectively, close to those obtained by the aethalometer method. The findings provide solid support for controlling fossil fuel sources to limit the impacts of BC on climate change and environmental degradation in the relatively clean region in China. [ABSTRACT FROM AUTHOR]

Tracing the aging progress of soot particles during transport is highly challenging. An Asian dust event could provide an ideal opportunity to trace the continuous aging progress of long-range-transported soot particles. Here, we collected individual aerosol particles at an inland urban site (T1) and a coastal urban site (T2) in China and a coastal site (T3) in southwestern Japan during an Asian dust event. Microscopic analysis showed that the number fraction of soot-bearing particles was 19 % and 16 % at T1 and T2 in China but surprisingly increased to 56 % at T3 in Japan. The dominant fresh soot (71 %) at T1 became partially embedded (68 %) at T2 and fully embedded (84 %) at T3. These results indicated that the tiny soot particles had lower deposition than other aerosol types and became more aged during the transport from T1 to T3. We quantified soot morphology using the fractal dimension and found an increasing trend of 1.65 at T1, 1.84 at T2, and 1.91 at T3. Furthermore, we found that the morphology compression of the soot aggregations was associated with secondary coating thickness and relative humidity. A unique mixing structure where multi-soot particles scattered in organic coatings instead of the sulfate core in individual core-shell particles was observed at T3 after the crossing of the East China Sea. The study provides understanding for important constraints of the soot morphological effects and provides a possible aging scale along with their transport pathway. These new findings will be helpful to improve optical calculations and regional climate modeling of soot particles during their transport in the atmosphere. [ABSTRACT FROM AUTHOR]

The variability of the lower tropospheric temperature inversion (TI) across China remains poorly understood. Using seven years' worth of high-resolution radiosonde measurements at 120 sites, we compile the climatology of lower tropospheric TI in terms of frequency, intensity, and depth during the period from 2011 to 2017. The TI generally exhibits strong seasonal and geographic dependencies. Particularly, the TI frequency is found to be high in winter and low in summer, likely due to the strong aerosol radiative effect in winter. The frequency of the surface-based inversion (SBI) exhibits a ''west low, east high'' pattern at 0800 Beijing time (BJT), which then switches to ''west high, east low'' at 2000 BJT. Both the summertime SBI and elevated inversion (EI) reach a peak at 0800 BJT and a trough at 1400 BJT. Interestingly, the maximum wintertime EI frequency occurs over Southeast China (SEC) rather than over the North China Plain (NCP), likely attributable to the combination of the heating effect of black carbon (BC) originating from the NCP, along with the strong subsidence and trade inversion in SEC. Correlation analyses between local meteorology and TI indicate that larger lower tropospheric stability (LTS) favors more frequent and stronger TIs, whereas the stronger EI under smaller LTS conditions (unstable atmosphere) is more associated with subsidence rather than BC. Overall, the spatial pattern of the lower tropospheric TI and its variability in China are mainly controlled by three factors: local meteorology, large-scale subsidence, and BC-induced heating. These findings help shed some light on the magnitude, spatial distribution, and underlying mechanisms of the lower tropospheric TI variation in China. [ABSTRACT FROM AUTHOR]

• The effect of Yellow River flood on characteristics of alluvial pollen are explored. • Pollen rhythms of two 25-m-long cores from suburban and urban areas were determined. • Pollen is not easy to be disturbed and can accurately identify sedimentary rhythms. • Pollen characteristics can indicate floods to some extent, even small-scale floods. Yellow River flooding has occurred many times near Kaifeng City resulting in the formation of a relatively complete sedimentary sequence, which provides a rare research carrier for exploring sedimentary rhythms in alluvium. In this paper, two 25-m-long cores were respectively obtained from suburban (JM core) and urban (SZ core) areas of Kaifeng City, China. Using detailed pollen data, grain size and our previous studies, we explore the effect of Yellow River flood events on the characteristics of alluvial pollen assemblages. Through cluster analysis of the pollen assemblages and pollen concentrations, we determined that there are 16 and at least 14 pollen zones/subzones (i.e. pollen rhythms) in the JM core and SZ core respectively. To aid an objective analysis we define a comprehensive rhythm from three other indicators, namely, grain size, black carbon and anthropogenic-biological elements. For the suburban JM core, less disturbed by human activity, each pollen rhythm has its corresponding comprehensive rhythm, and the upper and lower boundaries are basically the same. However, the number of pollen rhythms is found to be greater than the number of comprehensive rhythms, suggesting the precision of the pollen proxy is higher than the other three indicators. Similar phenomena were found in the SZ core, with significant human disturbance, which also suggests that the pollen proxy is less susceptible to human disturbance and can accurately identify sedimentary rhythms. Furthermore, the pollen concentration and its assemblage characteristics can indicate floods to some extent, even small-scale floods. This is thought to be related to circumstances where some Yellow River floods may have lasted for a long time, during which time there were several relatively short flood intervals due to seasonal and flood path changes; nevertheless, pollen rhythms can also be identified. Consequently, a pollen rhythm may not indicate a specific flood event. [ABSTRACT FROM AUTHOR]

A long-term, robust observational record of atmospheric black carbon (BC) concentrations at Fukue Island for 2009–2019 was produced by unifying the data from a continuous soot monitoring system (COSMOS) and a Multi-Angle Absorption Photometer (MAAP). This record was then used to analyze emission trends from China. We identified a rapid reduction in BC concentrations of (-5.8±1.5) % yr -1 or - 48 % from 2010 to 2018. We concluded that an emission change of (-5.3±0.7) % yr -1 , related to changes in China of as much as -4.6 % yr -1 , was the main underlying driver. This evaluation was made after correcting for the interannual meteorological variability (IAV) by using the regional atmospheric chemistry model simulations from the Weather Research and Forecasting (WRF) and Community Multiscale Air Quality (CMAQ) models (collectively WRF/CMAQ) with the constant emissions. This resolves the current fundamental disagreements about the sign of the BC emissions trend from China over the past decade as assessed from bottom-up emission inventories. Our analysis supports inventories reflecting the governmental clean air actions after 2010 (e.g., MEIC1.3, ECLIPSE versions 5a and 6b, and the Regional Emission inventory in ASia (REAS) version 3.1) and recommends revisions to those that do not (e.g., Community Emissions Data System – CEDS). Our estimated emission trends were fairly uniform across seasons but diverse among air mass origins. Stronger BC reductions, accompanied by a reduction in carbon monoxide (CO) emissions, occurred in regions of south-central East China, while weaker BC reductions occurred in north-central East China and northeastern China. Prior to 2017, the BC and CO emissions trends were both unexpectedly positive in northeastern China during winter months, which possibly influenced the climate at higher latitudes. The pace of the estimated emissions reduction over China surpasses the Shared Socioeconomic Pathways (SSPs with reference to SSP1, specifically) scenarios for 2015–2030, which suggests highly successful emission control policies. At Fukue Island, the BC fraction of fine particulate matter (PM 2.5) also steadily decreased over the last decade. This suggests that reductions in BC emissions started without significant delay when compared to other pollutants such as NOx and SO2 , which are among the key precursors of scattering PM 2.5. [ABSTRACT FROM AUTHOR]

Black carbon (BC) is an essential climate forcer in the atmosphere. Large uncertainties remain in BC's radiative forcing estimation by models, partially due to the limited measurements of BC vertical distributions near the surface layer. We conducted time-resolved vertical profiling of BC using a 356-m meteorological tower in Shenzhen, China. Five micro-aethalometers were deployed at different heights (2, 50, 100, 200, and 350 m) to explore the temporal dynamics of BC vertical profile in the highly urbanized areas. During the observation period (December 6–15, 2017), the average equivalent BC (eBC) concentrations were 6.6 ± 3.6, 5.4 ± 3.3, 5.9 ± 2.8, 5.2 ± 1.8, and 4.9 ± 1.4 μg m−3, from 2 to 350 m, respectively. eBC temporal variations at different heights were well correlated. eBC concentrations generally decreased with height. At all five heights, eBC diurnal variations exhibited a bimodal pattern, with peaks appearing at 09:00–10:00 and 19:00–21:00. The magnitudes of these diurnal peaks decreased with height, and the decrease was more pronounced for the evening peak. eBC episodes were largely initiated by low wind speeds, implying that wind speed played a key role in the observed eBC concentrations. eBC wind-rose analysis suggested that elevated eBC events at different heights originate from different directions, which suggested contributions from local primary emission plumes. Air masses from central China exhibited much higher eBC levels than the other three backward trajectory clusters found herein. The absorption Ångström exponent (AAE375–880) showed clear diurnal variations at 350 m and increased slightly with height. [ABSTRACT FROM AUTHOR]

Although regional haze adversely affects human health and possibly counteracts global warming from increasing levels of greenhouse gases, the formation and radiative forcing of regional haze on climate remain uncertain. By combining field measurements, laboratory experiments, and model simulations, we show a remarkable role of black carbon (BC) particles in driving the formation and trend of regional haze. Our analysis of long-term measurements in China indicates declined frequency of heavy haze events along with significantly reduced SO2, but negligibly alleviated haze severity. Also, no improving trend exists for moderate haze events. Our complementary laboratory experiments demonstrate that SO2 oxidation is efficiently catalyzed on BC particles in the presence of NO2 and NH3, even at low SO2 and intermediate relative humidity levels. Inclusion of the BC reaction accounts for about 90-100% and 30-50% of the sulfate production during moderate and heavy haze events, respectively. Calculations using a radiative transfer model and accounting for the sulfate formation on BC yield an invariant radiative forcing of nearly zero W m-2 on the top of the atmosphere throughout haze development, indicating small net climatic cooling/warming but large surface cooling, atmospheric heating, and air stagnation. This BC catalytic chemistry facilitates haze development and explains the observed trends of regional haze in China. Our results imply that reduction of SO2 alone is insufficient in mitigating haze occurrence and highlight the necessity of accurate representation of the BC chemical and radiative properties in predicting the formation and assessing the impacts of regional haze. [ABSTRACT FROM AUTHOR]

An improved two-sphere integration (TSI) technique has been developed to quantify black carbon (BC) concentrations in the atmosphere and seasonal snow. The major advantage of this system is that it combines two distinct integrated spheres to reduce the scattering effect due to light-absorbing particles and thus provides accurate determinations of total light absorption from BC collected on Nuclepore filters. The TSI technique can be calibrated using a series of 15 filter samples of standard fullerene soot. This technique quantifies the mass of BC by separating the spectrally resolved total light absorption into BC and non-BC fractions. To assess the accuracy of the improved system, an empirical procedure for measuring BC concentrations with a two-step thermal–optical method is also applied. Laboratory results indicate that the BC concentrations determined using the TSI technique and theoretical calculations are well correlated (R2=0.99), whereas the thermal–optical method underestimates BC concentrations by 35 %–45 % compared to that measured by the TSI technique. Assessments of the two methods for atmospheric and snow samples revealed excellent agreement, with least-squares regression lines with slopes of 1.72 (r2=0.67) and 0.84 (r2=0.93), respectively. However, the TSI technique is more accurate in quantifications of BC concentrations in both the atmosphere and seasonal snow, with an overall lower uncertainty. Using the improved TSI technique, we find that light absorption at a wavelength of 550 nm due to BC plays a dominant role relative to non-BC light absorption in both the atmosphere (62.76 %–91.84 % of total light absorption) and seasonal snow (43.11 %–88.56 %) over northern China. [ABSTRACT FROM AUTHOR]