Characteristics, formation mechanisms, and sources of non-refractory submicron aerosols in Guangzhou, China

Submicron aerosols (PM1) have more serious effect on the visibility, air quality, human health and climate change compared to coarse particles (particle size between 2.5 10 ?m). There is practical significance in understanding formation mechanisms sources of these particles. In this study, we conducted real-time measurements composition non-refractory submicron (NR-PM1) Guangzhou from 20 October 1 December, 2016, using a quadripole aerosol chemical speciation monitor (Q-ACSM). Overall, NR-PM1 was dominated by organics (48.2%), followed nitrate (NO3?, 20.3%), sulfate (SO42?, 17.4%), ammonium (NH4+, 11.4%), chloride (Cl?, 2.7%). The high contribution NO3? NO3?/SO42? mass ratios were observed high-PM episodes, suggesting that NOx emission control should be priority mitigating PM-pollution South China. Primary organic (POA) accounted for 51% as campaign average, POA increased with PM concentrations especially during indicating local emissions played very important role pollution. conversion SO2 SO42? aqueous, heterogeneous production may not dominant source NR-PM1, while regional transport likely main high-sulfate episodes. study related gas-phase reactions NO2 (photochemical reaction) daytime, (hydrolysis reaction N2O5) nighttime. Gas-phase would less severe polluted events. Particle acidity analyses showed generally acidic NH4+ enough fully neutralise SO42?, existing forms could (NH4)2SO4, NH4HSO4 or (NH4)3H(SO4)2. Controlling NH3 reduce concentration can probably feasible direction future if problem agriculture solved. Wind rose plots back-trajectory also demonstrated conducive increase concentration.