A Closure Study of Secondary Organic Aerosol Estimation at an Urban Site of Yangtze River Delta, China

Secondary organic aerosols (SOA) are crucial components of ambient particulate matters. However, their composition and formation mechanisms remain uncertain. To investigate the SOA evaluate various estimation approaches, a comprehensive measurement was conducted at an urban site, Changzhou, in Yangtze River Delta (YRD) region. 98 kinds volatile compounds (VOCs) were measured by online gas chromatography-mass spectrometer/flame ionization detector (GC-MS/FID). Non-refractory submicron matters (NR-PM1) Aerodyne Aerosol Chemical Speciation Monitor (ACSM). Both bottom-up i.e., VOCs oxidation yield method, top-down elemental carbon (EC) tracer method ACSM, combined with positive matrix factorization (PMF) utilized to estimate SOA. ACSM-PMF estimated highest concentration, followed EC method. from accounted for 43.2 ± 41.9% that suggesting existence missing precursors, e.g., semivolatile compounds. The influencing factors investigated good correlation odd oxygen rather than aerosol liquid water content found, importance photochemical