[Analysis of the Impact of Fireworks on Air Quality During the Spring Festival in Chengdu from 2019 to 2022].

Based on the observation data of air quality and PM components, the influence of fireworks on pollutant concentrations, PM components, and secondary transformation during the Spring Festival period from 2019 to 2022 in Chengdu were analyzed. The results indicated that the fireworks had a greater impact on the concentration of SO, PM, and PM than the other pollutants. During the centralized discharge of fireworks from 2019 to 2022, the average hourly concentrations of SO, PM, and PM increased by 6.7, 105.0, and 117.4 μg·m, with an increase of 135%, 236%, and 203%, respectively. During the centralized discharge period of fireworks, the contributions of fireworks to the SO, PM, and PM concentration were 10.0%-34.0%, 28.1%-31.3%, and 27.8%-34.6%, respectively. The impact time of fireworks on air quality decreased slightly, from 42 h in 2019 to 38 h in 2022; however, the impact on PM concentration fluctuated, and the impact in 2022 was similar to that in 2019. The main components of fireworks were K, Cl, Al, K, and Cl; the concentrations of these components were high and increased rapidly during the concentrated discharge, accounting for 5%-18% of PM, with an increase rate of 87%-1511%. The discharge of fireworks had little effect on NH, V, Cd, and Co, and the variation range was within±20%. Throughout the pollution period during the Spring Festival, the mass concentrations of the main components of fireworks were 4.9-31.7 times and 7.4-68.2 times that of the heavy pollution and good weather before the Spring Festival, and their proportions increased by 4%-8%. Secondary sources; fireworks; and biomass burning, coal burning, and industry were the main sources of PM during the 2019-2022 Spring Festival. The contribution rate of fireworks and biomass combustion was 13%-25%, with higher contribution rates in 2019 and 2022. From the perspective of the impact of meteorological conditions on fireworks discharge, high humidity, low wind speed, and low temperature will intensify the impact of firework discharge on air quality and vice versa. Wind speed mainly affected Al, K, Cl, and SO, whereas relative humidity mainly affected secondary components such as NO and NH.