Influence of fireworks displays on the chemical characteristics of PM_(2.5) in rural and suburban areas in Central and East China

摘要

To explore the spatial and chemical characteristics of PM_(2.5) pollution and the influence of fireworks displays on PM_(2.5) and its chemical components in rural areas in Central and East China, PM_(2.5) samples were collected at three rural sites and one suburban site in Henan and Shandong provinces during the 2016 Chinese New Year, and the chemical composition of PM_(2.5), including water-soluble inorganic ions (WSIIs), organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC) and trace elements (TEs) was analysed. The concentrations of PM_(2.5) at the four sites were significantly higher than the Grade I national standard of 35 μg/m~3, indicating serious PM_(2.5) pollution in rural and suburban areas. The contributions of secondary WSIIs to total WSIIs at the four sites were lower than in urban areas. The TEs in XP and LC were significantly enriched in PM_(2.5). A significant difference was found in the main chemical compositions of different sites. Fireworks displays directly increased the concentrations of PM_(2.5) and many chemicals, especially K~+, Cl~-, K, Cl, S, Cu and Sr, and concentrations of NO_3~- and NH_4~+ ions peaked after the fireworks period in the three rural sites, indicating the influence of firecrackers on the secondary formation of the precursors of NO_2. The ratio of WSOC/OC decreased during fireworks displays, indicating the direct influence of firecrackers on water insoluble organic matter. Fireworks-related ions were a key component of the aerosol at the four sites during fireworks displays, accounting for 28-38% of the total measured species.