[Distribution Characteristics of Air Pollutants and Aerosol Chemical Components Under Different Weather Conditions in Jiaxing]

Distribution characteristics of air pollutants and aerosol chemical components under different weather conditions were investigated in Jiaxing between May 1 and 31, 2015. The particulate matter (PM), gaseous pollutants, chemical components in PM_1.0, and aerosol number concentrations ranging from 10 nm to 10 μm were measured using the SHARP-5030 monitoring instrument, Thermo EMS system, Aerodyne Aerosol Chemical Speciation Monitor (ACSM), and Wide-Range Particle Spectrometer (WPS), respectively. The average concentrations of PM_2.5, PM_1.0, SO₂, NO₂, O₃, and CO were 52.8 μg·m^-3, 37.2 μg·m^-3, 10.3 μg·m^-3, 38.1 μg·m^-3, 92.1 μg·m^-3, and 1.2 mg·m^-3 during the observation period. The chemical components of OA, SO₄^2-, NO₃^-, NH₄⁺, and Cl^-in PM_1.0 had average concentrations of 2.18, 1.24, 0.87, 0.63, and 0.08 μg·m^-3, respectively. The aerosol number concentrations were mainly centralized in Aitken mode (20-100 nm), with a value of 12411.2 cm^-3. The nuclei mode aerosols (10-20 nm) followed the number concentrations with 4946.6 cm^-3. The concentration distributions and diurnal variations of PM and gaseous pollutants, and the distributions of chemical components of PM_1.0 varied under different weather conditions. The concentrations of chemical components were ranked in the order of OA > SO₄^2- > NO₃^- > NH₄⁺ > Cl^- on rainy days and sunny days, and in the order of OA > NO₃^- > SO₄^2- > NH₄⁺ > Cl^- on new particle formation (NPF) days. The OA and NO₃^- concentrations on NPF days were 1.61 and 1.42 times larger than those on sunny days, suggesting that the components of OA and NO₃^- were the main substances influencing the NPF events. Additionally, the diurnal variations of aerosols in different modes varied under different types of weather conditions.