Wet deposition and scavenging ratio of air pollutants during an extreme rainstorm in the North China Plain

AbstractAtmospheric wet deposition plays an important role in the supply of nutrients and toxic substances to terrestrial and aquatic environments. Although long-term (e.g. annual, multi-year) wet deposition is recorded well, pronounced and short-term changes in precipitation chemistry are less well investigated. In the present study, the precipitation chemistry and scavenging ratio of air pollutants were observed during an extreme torrential rain event (325.6 mm at the observation site) that occurred over 19–21 July 2016 in the North China Plain (NCP). The scavenging ratio of particles showed a similar spatial distribution to that of the precipitation amount in the NCP, indicating the efficient removal of particulate matter due to the large amount and precipitation intensity of the storm. In addition, the scavenging ratio of water soluble ions was larger than that of organics and gaseous pollutants such as SO2 and NO2, likely due to their differences in water solubility. Consequently, raindrops incorpora...