Atmospheric Deposition of Particulate Matter and Micropollutants as a Major Mass Transport Route to Surface Water in Winter: Measurement and Modeling in Beijing in 2014 and 2021

Deposition is a major route for atmospheric pollutants such as heavy metals and polycyclic aromatic hydrocarbons (PAHs) to transport to surface water. Here, we study Beijing, China, during the heavy haze period (2014) and the pandemic period (2021) to investigate the correlation between the atmospheric and surface water concentrations of 12 heavy metals and 16 PAHs. Pearson correlations and a series of back propagation (BP) neural network (NN) models are employed, and local meteorological conditions are included as input variables for the analysis. The surface water concentration of most pollutants analyzed correlate positively with humidity, PM_(2.5), PM₁₀, NO₂, SO₂, and CO, while negatively with the wind speed. The correlation coefficients are bigger in 2014 than in 2021, indicating accelerated gas–aqueous mass transport during haze episodes. The accurate prediction of the BP NN model in 2014 and 2021 presents itself as a promising tool in guiding future modeling efforts and policy changes.