Independent risk evaluation associated with short-term black carbon exposure on mortality in two megacities of Yangtze River Delta, China.

The adverse health effects of PM2.5 have been well demonstrated by many studies. However, as a component of PM2.5, evidence on the mortality risk of black carbon (BC) is still limited. In this study, based on the data of daily mean PM2.5 concentration, BC concentration, meteorological factors, total non-accidental (all-cause) and cardiovascular mortality in Shanghai and Nanjing during 2015-2016, a semi-parameter generalized additive model (GAM) in the time series and the constituent residual approach were employed to explore the exposure-response relationship between BC and human mortality in these two megacities of Yangtze River Delta, China. The main objective was to separate the health effects of BC from total PM2.5, and compare the difference of mortality ER related to BC original concentration and adjusted concentration after controlling PM2.5. Results showed that there were all significantly associated with daily mortality for PM2.5 and BC. The percentage excess risk (ER) increases in all-cause and cardiovascular categories were 1.68 % (95 % s 1.28, 2.08) and 2.16 % (95 % CI: 1.54, 2.79) with 1 µg/m3 increment in original BC concentration in Shanghai. And the ER in Nanjing was smaller than that in Shanghai. After eliminating PM2.5 confounding effects by a constituent residual approach, the BC residual concentration still had a strong significant ER. The ER for BC residual in Shanghai got an obvious increase, and ER of the cardiovascular mortality for all, females and males increased by 0.55 %, 1.46 % and 0.62 %, respectively, while the ER in Nanjing decreased slightly. It also revealed that females were more sensitive to the health risk associated with short-term BC exposure than males. Our findings provide additional important evidence and ER for mortality related to independent BC exposure. Therefore, BC emission reduction should be paid more attention in air pollution control strategies to reduce BC-related health burdens.

The impact of urbanization and consumption patterns on China's black carbon emissions based on input-output analysis and structural decomposition analysis.

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.

[Analysis of Transport Pathways and Potential Sources of Atmospheric Particulate Matter in Zigong, in South of Sichuan Province].

Atmospheric particulate matter pollution in Zigong City in southern Sichuan is quite severe. The average concentrations of PM10 and PM2.5 from 2015 to 2018 were (95.42±9.53) µg·m-3 and (65.95±6.98) µg·m-3, with an obvious trend of decline. The concentrations of PM10 and PM2.5 in winter were much higher than in other seasons, with the highest average concentrations being(138.08±52.29) µg·m-3 and (108.50±18.05) µg·m-3 in January, respectively, whereas in summer, the average concentrations were lowest. The average ratio of PM2.5 to PM10 is 69.12%, and the ratio in winter is about 1.17 times that in summer; thus, PM2.5 is mainly responsible for the air pollution. To explore the potential sources of fine particulate matter (PM2.5) in Zigong City and the pollution contributions of different sources in different seasons, the concentration of PM2.5 in Zigong and the daily trajectory after 72 h were calculated and clustered by the combined use of a variety of potential source analysis methods and data. These methods and data included the hybrid single particle lagrangian integrated trajectory (HYSPLIT) model, global data assimilation system (GDAS) meteorological data, potential source contribution analysis (PSCF), and concentration of weight trajectory analysis (CWT). The results showed that the area near Zigong is mostly controlled by southeasterly, westerly, and northwesterly winds in all seasons, and the high PM2.5 concentration is mostly located in the low-wind-speed zone of 0-2 m·s-1. The influence of different seasons and transport routes on PM2.5 pollution in Zigong is significant. In spring, it is mainly affected by short-distance air flow from the west and north; in summer, the pollution mainly comes from the southeast air flow of short-distance transportation; in autumn, it is mainly affected by short-distance transportation air flow from Ziyang, Suining, Chongqing, and Neijiang; and in winter, it is not only affected by the surrounding cities such as Ziyang, Suining, and Neijiang but also by the long-distance transportation air flow from central Tibet. In general, the potential source area of particulate matter in Zigong City is mainly located in the border area between the west of Chongqing and the south of Sichuan. In winter, the main contribution area is at its widest, while in summer, the potential source area is smallest.