Supplementary material to "Dominant role of emission reduction in PM<sub>2.5</sub> air quality improvement in Beijing during 2013–2017: a model-based decomposition analysis"

Elevated Formation of Particulate Nitrate From N2O5 Hydrolysis in the Yangtze River Delta Region From 2011 to 2019

“…The highest concentration of PM 2.5 , which occurred in December 2013, had an average mass concentration of 128.3 (±86.9) μg/m 3 . The Chinese government has introduced several air pollution control policies since September 2013, leading to a significant drop in PM 2.5 concentration (Cheng et al., 2019). To assess the role of the Action Plan in reducing the mass concentrations of PM 2.5 , three time periods were identified during 2011–2019, namely, 2011–2013 (Pre‐Action Plan), 2014–2017 (Action Plan), and 2017–2019 (Post‐Action Plan).…”

“…The reduction in K + was the most pronounced, followed by Ca 2+ , Cl − , and EC. The annual decrease rates of K + , Ca 2+ , Cl−, and EC were 30.0%, 14.4%, 10.8%, and 9.5%, respectively, which was attributed to the nationwide control of fugitive dust, biomass burning, and coal combustion in the past few years (An et al., 2021; Cheng et al., 2019; Sun et al., 2013). Evident reduction of primary components in PM 2.5 may change the chemical characteristics of PM 2.5 .…”

Thermodynamic Modeling Suggests Declines in Water Uptake and Acidity of Inorganic Aerosols in Beijing Winter Haze Events during 2014/2015–2018/2019

“…Several studies (using chemical transport models or statistical models) have investigated the influences of reduced emissions and meteorology on PM concentrations in Beijing for recent years. 43,70,71 They generally suggested a major role of emission and a minor role of meteorology. Cheng N. et al 70 found, different from the other seasons, that wintertime PM 2.5 did not decrease significantly (on a 90% confidence level) during 2013−2016 due to unfavorable meteorological conditions.…”

“…Cheng N. et al 70 found, different from the other seasons, that wintertime PM 2.5 did not decrease significantly (on a 90% confidence level) during 2013−2016 due to unfavorable meteorological conditions. Cheng J. et al 71 showed that PM 2.5 mass concentrations in the 2017/2018 winter would increase by about 80% if the meteorological conditions were the same with 2016/2017 winter, although there was a negative bias in the modeled PM 2.5 compared to observations in 2016/2017. More stringent emission control measures, including the suspension of industrial activities and the replacement of coal with natural gas, were implemented in the 2017/2018 winter over Beijing and surrounding regions in order to meet the target of PM 2.5 concentration for the 2013−2017 Clean Air Action Plan and were suggested to significantly reduce PM concentrations during this winter season.…”

Emission Sector Impacts on Air Quality and Public Health in China From 2010 to 2020

“…The reductions in PM 2.5 concentrations over 2015–2017 have been attributed to reductions in anthropogenic emissions, as a result of the Air Pollution Prevention and Control Action Plan of 2013–2017 (Cheng et al., 2019; Ding et al., 2019; K. Li et al., 2019, 2020; Silver, Conibear, et al., 2020; Zhai et al., 2019; B. Zhao et al., 2018). The plan required PM 2.5 concentrations to decline by 25% in Beijing–Tianjin–Hebei, 20% in the Yangtze River Delta, and 15% in the Pearl River Delta.…”