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

Abstract

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 PM1.0, 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 PM2.5, PM1.0, 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, SO42-, NO3-, NH4+, and Cl-in PM1.0 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 PM1.0 varied under different weather conditions. The concentrations of chemical components were ranked in the order of OA > SO42- > NO3- > NH4+ > Cl- on rainy days and sunny days, and in the order of OA > NO3- > SO42- > 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.