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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]

The vertical distributions of BC mass concentration (m BC) during a winter pollution period in 2017 over Chengdu, a megacity in the Sichuan Basin, China, were measured by a micro-aethalometer equipped on a tethered balloon. This observation experienced severe air pollution with an averaged ground BC of 11.1 μg·m−3, which is higher than two times the annual mean in Chengdu for 2018. The available 68 BC vertical profiles are grouped in to five types: Type A (18%) is the uniform vertical distribution of BC with an unrecognizable mixing layer (ML) height; BC in Type B (26%) is also uniformly distributed in the ML while decreases rapidly above the ML; Type C (7%) is a unimodal distribution with BC peak within the ML when the suspended temperature inversion forms; BC in Type D (29%) is accumulated in the near-ground layer and quickly decreases with height; Type E (20%) is the bimodal or trimodal distribution with BC peaks around the top of ML. Types A and B dominate from noon to afternoon, and Types C–E play critical roles during the evening and night. The different vertical patterns of BC are mainly associated with the evolution of the ML and the local emissions. For all the five types, the calculated radiative forcing of BC (f BC) is negative at the surface but positive at the top of profile (TOP), indicating the net absorption of radiation by the atmosphere due to BC. The absolute values of f BC at the surface and the TOP are increased with the increase of columnar BC loading, and there is no significant difference in f BC at the TOP and the surface among different patterns when the same BC loading is considered. However, the vertical distribution of atmospheric heating rate contributed by BC (h BC) is highly related to BC's vertical profile. The uniform distributed BC can result in a positive gradient of h BC with altitude, and thus, enhance the stability of the atmosphere. The plateau terrain induced small-scale secondary circulation and relatively lower thermal inversion in the west of the Sichuan basin have an essential effect on the vertical distribution of aerosols and can contribute to an accumulation of aerosols at 0.8–1.4 km above ground level. This study would hopefully have a preliminary understanding of the vertical distribution of BC in the Sichuan Basin, and a vital implication for accurately estimating direct radiative forcing by BC in this region. • Vertical profiles of black carbon (BC) are measured by a micro-aethalometer equipped on a tethered balloon over Chengdu. • Five types of BC vertical profiles are grouped. • Vertical distribution of BC radiative forcing and heating rate for the five types of BC are calculated and compared. • The secondary circulation and low thermal inversion can contribute to the aerosol layer above the observation site. [ABSTRACT FROM AUTHOR]

Epidemiological studies have shown that outdoor black carbon (BC) has higher health risks than other constituents and the total fine particulate matter (PM 2.5). In this study, we estimated premature mortality attributed to BC in China in 2013 using a health impact model combined with annual average BC concentrations predicted using the Community Multi-scale Air Quality model. Source contributions to BC from six different source sectors were estimated using the source-oriented method, including residential, industrial, transportation, open burning, power, and other sources. The sensitivity of BC-related premature mortality to emission reductions in different sources was quantified in different regions of China. The results showed that the total all-cause premature mortality related to BC was approximately 1,436,957 (95% CI: 998,746–2,029,210) in China in 2013. Residential, industrial, and transportations sources were the three main sources of BC-induced premature mortality. Central China, Yangtze River Delta, and Sichuan Basin had the highest BC-induced mortality due to a high level of emissions and a dense population. A sensitivity test by assuming the same exposure-response coefficient of BC as the total PM 2.5 showed the number of deaths was 265,122 thousand (95% CI: 541,90, 445,943) which can be treated as the lower limit of the BC-related mortality in China. Despite the uncertainties in estimates, it is suggested that reducing BC emissions in China would lead to significant health benefits. Controlling BC from industrial and transportation sources would bring more relative mortality reductions, from a percentage point of view, in most provinces of China. [Display omitted] [ABSTRACT FROM AUTHOR]

Worldwide epidemiological studies have demonstrated that short-term associations of particulate matter (PM), might be further complicated by ambient temperatures, and increase human mortality. In China, among various PM indices, the health effects of black carbon (BC) are less understood due to the lack of data availability. Additionally, it is unclear how temperature modifies simultaneous and adverse effects of BC, and fine (PM size <2.5 μm; PM 2.5), and coarse particles (PM 2.5-10), on mortality outcomes. We adopted time-series Poisson generalized additive models to investigate temperature modifying effects on the association between three different PMs (BC, PM 2.5 , and PM 2.5-10) and mortality (non-accidental, respiratory and cardiovascular mortality) in Beijing, China, from 2010 to 2016. Average daily BC, PM 2.5 , and PM 2.5-10 concentrations were 4.95, 72.3, and 52.1 μg/m3, respectively, which were all significantly associated with daily mortality. High temperature strongly amplified effects of BC, PM 2.5 , and PM 2.5-10 on human mortality, especially BC effects that were most pronounced at >28 °C. Harmful effects were estimated for increases in non-accidental, respiratory, and cardiovascular mortality per interquartile increments in BC (4.11 μg/m3), PM 2.5 (62.37 μg/m3), and PM 2.5-10 (46.71 μg/m3) concentrations from the moving average of current and previous day (lag01) under high temperature (>28 °C). Mortality increases in non-accidental, respiratory, and cardiovascular categories were 5.12% (95% confidence interval [CI]: 4.79, 5.45), 7.41% (95%CI: 6.42, 8.40), and 6.36% (95%CI: 2.45, 10.3) for BC; 3.85% (95%CI: 3.27, 4.43), 6.64% (95%CI: 5.63, 7.65), and 4.54% (95%CI: 3.31, 5.78) for PM 2.5 ; and 2.56% (95%CI: 1.45, 3.67), 3.41% (95%CI: 1.53, 5.29), and 3.19% (95%CI: 2.44, 3.94), for PM 2.5-10 , respectively. These findings suggest that controlling the emission of ambient particles, especially BC, and improving air quality during summer would substantially benefit population health. Furthermore, BC should be considered as a crucial air quality indicator to reflect PM health risk. Image 1 • To test the synergistic effects of temperature and black carbon (BC) on mortality. • High temperature amplified the harmful effects of BC and PM on mortality. • The modifying effects of temperature on BC were different from that on PMs. [ABSTRACT FROM AUTHOR]

Black carbon (BC) aerosol is an important influence factor of global climate change, which can absorb visible light and part of infrared light strongly and affect climate change. Black carbon aerosol is also one of the main components of PM2.5. It can adsorb some toxic and harmful substances, affecting human health. Black carbon aerosol can participate in atmospheric chemical processes and affect the composition of the atmosphere. Sichuan Basin lies in the southwest China, there are two mega-cities of Chengdu and Chongqing. Due to the unique topographic conditions and the rapid development of urbanization, the pollution diffusion condition in Sichuan Basin is poor, which often results in the accumulation of pollutants, especially in winter time.In order to investigate the BC concentration evolution and its variations and impacts in this special region, surface BC concentration was observed using AE33 instrument from September 2017 to August 2018 in CUIT (Chengdu University of Information Technology) campus located in western surburb of Chengdu and vertical structures were monitored using MA200 multiband black carbon micro-instrument in December 2017 in Jianyang city of Sichuan Province. The distance between CUIT station and Jianyang station is about 60 km. The observation data showed that, the annual concentration of BC is 5.88±2.49µg/m3. The concentration of BC in winter was much higher (8.16±3.19µg/m3) than other seasons, BC concentration in summer was relative low (2.77±1.17µg/m3), in spring and autumn BC was about 5.20±2.41µg/m3. The diurnal variation of BC concentration was also obvious due to the local meteorological conditions and anthropogenic activities. It appeared that BC high peak value in the morning and night and low value in the afternoon. The experiment data showed that the vertical distribution of BC concentration varied with different weather patterns and boundary layer structures. Usually BC concentration was high from surface to about 500m height, the value was relative low (about 3~6µg/m3) at normal days. When stable weather and inversion temperature occurred in lower layer, BC concentration within 200m could be very high more than 12 µg/m3, as well as the PM2.5 was high resulting heavy pollution. In Sichuan basin, the ratio of BC and PM2.5 was about 0.08, which means BC account for 8 percent of PM2.5 on average. The further deep investigation in the source of BC and PM2.5 and their formation process, impact on local and regional weather and climate and their effect on human health will be conducted. [ABSTRACT FROM AUTHOR]

Black carbon (BC) is one of the most important factors affecting the uncertainty of global climate change, as well as affecting human health by absorbing harmful substances in the environment. Understanding how human activities drive BC emissions can help formulate effective emission reduction policies. However, regional differences in social and economic activities determine the factors driving BC emission change in different regions/provinces, leading to the non-applicability of national-level emission reduction policies among the provinces. Therefore, it is necessary to develop a provincial-level analysis to shape refined policies for BC emission reduction. Here, we subdivided China's total BC emissions into 30 provinces based on previous work and used the multi-regional input-output model and complete average decomposition analysis to explore how BC emission intensity, intermediate inputs structural adjustment, local final demand, inter-provincial trade, and international exports drive BC emissions during 2007–2017. The results showed that BC emission intensity was an important emission reduction factor for all provinces in China. As for the effect of intermediate inputs structural adjustment, it had a negative effect during 2007–2012. However, during 2012–2017, as the tertiary industry had become the biggest factor in promoting economic development, the impact of the intermediate input structure on BC emissions had become a positive contribution, which showed that current industrial structure adjustment was not conducive to BC emissions reduction. Local final demand, inter-provincial trade, and international exports were the main factors causing the increase in BC emissions in each province as well. Southwestern regions and heavy industrial provinces emitted additional high BC emissions due to the huge final demand in the Eastern coastal regions. More targeted policies can be formulated by determining BC emission reduction responsibilities based on their driving factors at the provincial and sectoral levels and the development of emission reduction measures for each province. • BC emission intensity and structural adjustment were the main factors decreasing the emission increment of BC. • Local final demand, inter-provincial trade, and exports were the main factors causing the increase in BC emissions. • The emission effect of inter-provincial trade gradually concentrated from eastern region to central and western regions. [ABSTRACT FROM AUTHOR]

Due to its twofold effects on climate change and air quality, black carbon (BC) is of wide concern in the atmospheric sciences. Considerable uncertainty exists as to the health effects of atmospheric BC for the limited epidemiological and toxicological studies. As combustion-derived BC is one important component of PM 2.5 (particles with aerodynamic diameters less than 2.5 μm), the question remains of whether or not BC may play an important role in PM 2.5 -related health risks. To quantitatively analyze the short-term health effects of BC and PM 2.5 , a confounder-adjusted semi-parametric generalized additive model (GAM) of a time series study was used to calculate the concentration-response relationship between BC and PM 2.5 and daily cardiovascular disease (CVD) mortality from 2006 to 2011 in Beijing. During the study period, the mean daily concentrations of BC and PM 2.5 were 6.8 μg/m3 and 75.9 μg/m3, respectively. The results showed that BC was significantly associated with CVD mortality, and an interquartile range (IQR) increase in BC (5.7 μg/m3) and PM 2.5 (64. 5 μg/m3) were associated with 2.70% (95% CI: 2.20, 3.21) and 4.06% (95% CI: 3.47, 4.65) increase in CVD mortality. The health risk associated with BC may less than that of PM 2.5. When adjusted for nitrogen dioxide (NO 2) and sulfur dioxide (SO 2), the effects of BC remained statistically significant. It showed the relatively difference between BC and PM 2.5 when it comes to the modification effects of age, gender and educational attainment. These findings provide valuable evidence to the rare studies of the concentration-response relationship of BC with human health in developing countries. Image 1 • Few studies in Asian developing countries have examined the health effects of BC. • We observed significant associations of BC and PM 2.5 with daily cardiovascular mortality in Beijing. • The health risk associated with ambient BC may less than that of PM 2.5. [ABSTRACT FROM AUTHOR]

In-situ measurements of aerosol optical properties were conducted at Mt. Huang from September 23 to October 28, 2012. Low averages of 82.2, 10.9, and 14.1 Mm−1 for scattering coefficient (σ sp, neph, 550), hemispheric backscattering coefficient (σ hbsp, neph, 550), and absorption coefficient (σ ap, 550), respectively, were obtained. Atmospheric aging process resulted in the increase of σ ap, 550 but the decrease of the single scattering albedo (ω 550) at constant aerosol concentration. However, the proportion of non-light-absorbing components (non-BCs) was getting higher during the aging process, resulting in the increase of aerosol diameter, which also contributed to relatively higher σ sp, neph, 550 and ω 550. Diurnal cycles of σ sp, neph, 550 and σ ap, 550 with high values in the morning and low values in the afternoon were observed closely related to the development of the planetary boundary layer and the mountain-valley breeze. BC mixing state, represented by the volume fraction of externally mixed BC to total BC (r), was retrieved by using the modified Mie model. The results showed r reduced from about 70% to 50% when the externally mixed non-BCs were considered. The periodical change and different diurnal patterns of r were due to the atmospheric aging and different air sources under different synoptic systems. Local biomass burning emissions were also one of the influencing factors on r. Aerosol radiative forcing for different mixing state were evaluated by a "two-layer-single-wavelength" model, showing the cooling effect of aerosols weakened with BC mixing state changing from external to core-shell mixture. Unlabelled Image [ABSTRACT FROM AUTHOR]