Influence of High Relative Humidity on Secondary Organic Carbon: Observations at a Background Site in East China

Impacts of COVID-19 on Air Quality over China: Links with Meteorological Factors and Energy Consumption

“…affect several aspects of society, including human mobility, energy consumption, and lifestyle, it is important to understand the effects of behavioral changes on air quality by analyzing these factors collectively. Furthermore, meteorological factors are key determinants of air quality (e.g., Tie et al, 2017;Liang et al, 2019) and must be considered when estimating the precise contribution of human activities to air quality degradation.…”

“…The low NO in can be attributed to new environmental regulations for air pollution implemented in China (Duncan et al, 2016). Although laws and regulations for air pollution mitigation have been modified and improved over a long time period (Yan, 2020), the most stringent action plan to date was established in 2013 (Zhang et al, 2019 This approximately 30% reduction in NO 2 was larger than the AOD reduction of around 20%, reflecting the shorter atmospheric residence time of NO 2 than of aerosols. The remarkable reduction of NO 2 during the Lockdown period can be suggested to be primarily due to a reduction in transportation (Zhou, 2020).…”

“…Water vapor in the atmosphere can increase AOD by increasing the aerosol size (Khatri and Ishizaka, 2007). Additionally, an increased aerosol size can lead to more rapid multiphase reactions and secondary aerosol formation (Liang et al, 2019), thereby increasing the aerosol number concentration (Tie et al, 2017). Thus, the high PWC in 2020 compared with 2019 was more favorable to increase aerosol loading in the atmosphere.…”

“…This decrease can increase aerosol loading by two pathways. First, it can increase the relative humidity, aerosol, and ozone concentration near the surface (Zhu et al, 2018), creating favorable conditions for the heterogenous chemistry of aerosols (Liang et al, 2019).…”

Seasonal variations of water-soluble ions in PM10 at a WMO/GAW station in the Yangtze River Delta, China

“…1(b) and (c), the levels of chemical compositions in PM 10 were various in four seasons, which was associted with different meteorological conditions (temperature, relattive humidity, wind speed and direction, etc. ), the intensity of emission sources, as well as pollution transportation [3,15,16]. The total measurement ions contributed for 30.24-45.08% to PM 10 in four seasons.…”