Chemical Characterization, Source, and SOA Production of Intermediate Volatile Organic Compounds during Haze Episodes in North China

The growth of secondary organic aerosols (SOA) is a vital cause the outbreaks winter haze in North China. Intermediate volatile compounds (IVOCs) are important precursors SOA. Therefore, chemical characteristics, source, and SOA production IVOCs during episodes have attracted much attention. Hourly time resolution IVOC samples two collected Hebei Province China were analyzed this study. Results showed that: (1) concentration measured was within range 11.3~85.1 μg·cm−3 episodes, with normal alkanes (n-alkanes), polycyclic aromatic hydrocarbons (PAHs), branched (b-alkanes), residue unresolved complex mixture (R-UCM) accounting for 8.6 ± 2.3%, 6.8 2.2%, 24.1 3.8%, 60.5 6.5% IVOCs, respectively. NC12-nC15 n-alkanes, naphthalene its alkyl substitutes PAHs, b-alkanes B12–B16 bins, R-UCM bins main components, 87.0 0.2%, 87.6 2.9%, 85.9 5.4%, 74.0 8.3%, (2) Based on component characteristics ratios n-alkanes/b-alkanes emission sources hourly variation coal combustion (CC), biomass burning (BB), gasoline vehicles (GV), diesel (DV)were identified as Province. (3) During temporal estimated based different methods (such concentration, OC/ECmin tracer, PMF model) similar; however, absolute values different. This difference may be due to transformation affected by various factors such from meteorological conditions, atmospheric oxidation, etc.