Spatial distributions of secondary organic aerosols from isoprene, monoterpenes,β-caryophyllene, and aromatics over China during summer

摘要: Filter-based particle samples were simultaneously collected at 14 sites across 6 regions of China during the summer 2012. These filters analyzed for secondary organic aerosol (SOA) tracers from biogenic precursors (isoprene, monoterpenes, and β-caryophyllene) anthropogenic aromatics. The sum all SOA ranged 29.9 to 371 ng m−3 with majority isoprene (123 ± 78.8 ng m−3), followed by monoterpenes (10.5 ± 6.64 ng m−3), β-caryophyllene (5.07 ± 3.99 ng m−3), aromatics (2.90 ± 1.52 ng m−3). highest levels observed in East China, whereas concentrations aromatic tracer, 2,3-dihydroxy-4-oxopentanoic acid (DHOPA), occurred North China. All exhibited positive correlations temperature, most likely resulting enhanced volatile compounds (BVOCs) emissions photochemistry high-temperature regions. Among tracers, low-NOx products 2-methyltetrols largest mass concentration. However, certain urban sites, contribution high-NOx product 2-methylglyceric was significantly higher, implying a greater influence NOx on formation areas. For monoterpene ratio first-generation (cis-pinonic plus pinic acid) high-generation (3-methyl-1,2,3-butanetricarboxylic negative correlation amount products, indicating that this could serve as an indicator aging SOA. 0.89 21.0, average 7.00 ± 6.02, among observation suggesting generally fresh over summer. As typical DHOPA higher than remote sites. further used attribute origins via SOA-tracer method. total carbon (SOC) estimated be range 0.37 2.47 μgC m−3 0.81 5.44 µg m−3, respectively, eastern Isoprene (46 ± 14%) (27 ± 8%) two major contributors SOC every region. In contributor. Our ground-based observations suggest are important