Chemistry of Atmospheric Fine Particles During the COVID‐19 Pandemic in a Megacity of Eastern China

Abstract

Atmospheric particulate matter (PM) exerts significant impacts on air quality, climate change, and public health (IPCC, 2013; West et al., 2016). The megacities in developing countries, such as China and India, are facing severe air pollution, especially the fine particle (PM 2.5) problem because of their fast-growing economy and urbanization in past decades (Fu & Chen, 2017; Gurjar et al., 2016). To mitigate air pollution, the Chinese State Council implemented the "Air Pollution Prevention and Control Action Plan" in 2013 (Chinese State Council, 2013). As a consequence, anthropogenic emissions of major air pollutants decreased largely (e.g., 59% for SO 2 , 21% for NO x , and 33% for primary PM 2.5) in China during 2013-2017 (Q. Zhang & Geng, 2019). However, despite large reductions in primary emissions, heavy haze episodes still occur in

Trans‐Regional Transport of Haze Particles From the North China Plain to Yangtze River Delta During Winter

“…The average PM 2.5 concentration was 63 μg m −3 during winter in 2017 in Hangzhou (Table S1), which is lower than the Grade II standard value of 75 μg m −3 . Regional haze events frequently appeared in the YRD in winter because of regional emissions from urban vehicle exhausts and industrial activities (Liu, Zhang, et al, 2020;Xu, Zhang, et al, 2020), as well as the TRT of air pollutants from the NCP (Li, Wang, et al, 2019;Ming et al, 2017). Compared with the NCP, there are no coal-fired heating activities in villages and central heating in urban areas in the YRD during winter.…”

Changes in Source‐Specific Black Carbon Aerosol and the Induced Radiative Effects Due to the COVID‐19 Lockdown

“…Most current studies have focused on the impact of reduced anthropogenic emissions on aerosols (Fan et al., 2020; Liu et al., 2021; Y. Wang et al., 2020) and the important role played by secondary aerosols in causing air pollution during the lockdown (Huang et al., 2020). Few studies pay attention to the corresponding climatic effects induced by the drastic aerosol change resulting from the anthropogenic emissions reduction during the lockdown (Gettelman et al., 2020).…”

Impact of the first induced COVID-19 lockdown on air quality in Israel

“…Their synergistic observation analyses and model simulations showed that anomalously high humidity promoted aerosol heterogeneous chemistry, along with stagnant airflow and uninterrupted emissions from power plants and petrochemical facilities, contributed to severe haze formation. Also, due to nonlinear production chemistry and titration of ozone in winter, both reduced nitrogen oxides that resulted in ozone enhancement in urban areas, further increasing the atmospheric oxidizing capacity and facilitating secondary aerosol formation ( Liu et al, 2021 ;, Huang et al, 2021 ).…”