Real-time non-refractory PM1 chemical composition, size distribution and source apportionment at a coastal industrial park in the Yangtze River Delta region, China

This study present real-time measurements of the chemical composition and particle number size distributions (PNSD) of submicron particulate matter (PM 1 ) in winter at a coastal industrial park in the Yangtze River Delta region of China. Positive matrix factorization (PMF) analysis identified three PNSD factors and three organic aerosol (OA) factors. Contributions and potential source regions of these factors were investigated for four typical periods during the PM 1 formation and dissipation process. Results show that the relative contributions from aged 250 nm- factor, fresh 35 nm- and 80 nm- factors were strongly affected by local fresh emissions and regional new particle formation. The non-refractory PM 1 measured by Aerodyne aerosol chemical speciation monitor is indicative of the chemical composition of aged 250 nm-factor, but not fresh 35 nm- and 80 nm-factors. The contributions of NO 3 − and SO 4 2− to NR-PM 1 were largely dictated by whether the air mass trajectory went over the sea or the continent. NO 3 − was abundant (up to 44% of NR-PM 1 ) in cold and dry continental air masses, while SO 4 2− formation (up to 39% of NR-PM 1 ) was preferred in humid and warm marine air masses. Among the three OA source factors, more-oxidized oxygenated OA (MO-OOA) was the most abundant OA factor (44–66% of total OA) throughout the entire field campaign, while an enhanced contribution of 39% from hydrocarbon-like OA (HOA) was observed prior to heavy pollution period. On average, secondary components SO 4 2− , NO 3 − , NH 4 + , MO-OOA and less-oxidized oxygenated OA (LO-OOA) contributed 90 ± 7% of NR-PM 1 , while primary components HOA and Cl − accounted for the remaining 10 ± 7%. • PMF was applied on particle number size distribution and chemical composition data. • Primary and secondary fractions of NR-PM 1 were discriminated based on PMF results. • Four typical periods during the PM formation and dissipation process were investigated. • Source contributions and potential source regions were identified for the four periods.