Investigation of the impact mechanisms and patterns of meteorological factors on air quality and atmospheric pollutant concentrations during extreme weather events in Zhengzhou city, Henan Province

Abstract

Quantitative analysis of the complex relationships between meteorological factors and atmospheric pollution under extreme weather conditions is of crucial importance for future climate change assessment and air pollution control policy implementation. In this study, we used a multi-factor generalized additive model (MGAM) to investigate the nonlinear interaction between meteorological factors and atmospheric pollutants during the “7–20″ extreme precipitation event (EP) in 2021 and the heat wave event (EH) in June 2022 in Zhengzhou City. The results showed that atmospheric pollutant concentrations decreased significantly (p < 0.05) relative to the baseline concentrations during the study period. EH events usually have lower humidity than EP events, so the negative effects of precipitation and relative humidity on pollutant concentrations were significantly higher during the EP than during the EH. In contrast, the effect of temperature on O3 concentration was significantly higher than that on other pollutants during the EH. The results of MGAM indicated the changes in pollutant concentrations were significantly nonlinearly influenced by multiple meteorological factors, both during the EP and EH periods. During the EP, O3 concentration peaked when relative humidity was below 70% and temperature was around 26 °C, and PM2.5 concentration was highest when relative humidity was about 80% and hourly precipitation was below 50 mm. During the EH, high temperature (>35 °C) and lower relative humidity (<35%) aggravated atmospheric pollution. Meanwhile, we found that O3 concentration peaked in when relative humidity was below 20% and temperature reached 40 °C. In addition, there was temporal heterogeneity in the interaction effects of different meteorological factors on atmospheric pollutants during the EP and EH. Our findings have implications for the continued implementation of stringent local air quality policies and the adoption of effective air pollution prevention and control measures.