TITLE:
Chemical Characteristics of Precipitation and Its Effects on Atmospheric Pollutants in Suburban Areas of Cangzhou, China
AUTHORS:
Jian Wang, Sisi Li, Yanan Zhao, Yufeng Mao, Na Mao, Qingshui Yu, Wenyu Zhang, Cuihua Zhang, Mei Xu
KEYWORDS:
Atmospheric Particles, Atmospheric Precipitation, Scavenging Effect, Chemical Composition
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.14 No.10,
October
30,
2026
ABSTRACT: Observations of precipitation chemistry and major atmospheric pollutant mass concentrations in suburban Cangzhou in 2021 were used to characterize regional precipitation chemistry. Precipitation measurements included pH, electrical conductivity, and water-soluble ion concentrations. Pollutant variations were compared between rainy days and non-rainy days. The observed pH range of 6.18 - 8.02 and volume-weighted mean of 6.71 suggested that precipitation in the study area was not acidified during the sampling period. The electrical conductivity ranged from 6.85 to 290 μS/cm, and the volume-weighted mean was 40.29 μS/cm. The total ion concentrations ranged from 86.14 to 3221.58 μeq/L, with a volume-weighted mean of 366.13 μeq/L. Ca2+ and
NH
4
+
were the dominant cations, accounting for 46.82% and 25.33% of the total cation concentration, respectively.
NO
3
−
and
SO
4
2−
were the principal anions, accounting for 45.57% and 40.08% of the total anion concentrations, respectively. On rainy days, mass concentrations of PM2.5, PM10, SO2, NO2, and CO were lower than those on non-rainy days by 27.97%, 40.62%, 27.32%, 25.36%, and 17.78%, respectively. These differences demonstrated that the scavenging effect by precipitation varied among atmospheric pollutants and was most pronounced for PM10. The regulatory effects of precipitation differed among atmospheric pollutants. Together with improved atmospheric dispersion, wet deposition effectively reduced PM2.5, PM10, NO2, SO2, and CO concentrations, with PM10 and SO2 being the most sensitive to rain. Conversely, the increase in O3 concentrations on rainy days was attributed to changes in atmospheric composition and solar radiation conditions.