Polar organic tracers in PM2.5 aerosols from an inland background area in Southwest China: Correlations between secondary organic aerosol tracers and source apportionment
Li Li , Wei Lai , Jinguo Pu , Hengqin Mo , Dongjue Dai , Guilin Wu , Shihuai Deng
DOI:10.1016/j.jes.2017.06.002
Received January 07, 2017,Revised January 01, 1900, Accepted June 02, 2017, Available online June 15, 2017
Volume 30,2018,Pages 281-293
PM2.5 aerosol samples were collected over 12 hr and 24 hr intervals in an inland background area, Gongga Mountain National Nature Reserve (hereafter shortened to Gongga), during the summer of 2011. Polar organic tracers, inorganic ions and meteorological data were measured. The purpose of this work was to investigate the variation patterns, formation and sources of the secondary organic aerosol tracers in the studied atmosphere. The average concentrations of isoprene oxidation products, α-pinene oxidation products, β-caryophyllinic acid, sugars, sugar alcohols and anhydrosugars were 88.6 ± 106.1, 3.6 ± 5.7, 0.13 ± 0.30, 13.6 ± 13.1, 31.9 ± 31.4 and 14.8 ± 10.7 ng/m3 respectively in all aerosol samples. The aged α-pinene second organic aerosol (SOA) tracers (i.e., 3-hydroxyglutraric acid (3HGA), 3-hydroxy-2,2-dimethylglutaric acid (HDMGA), 3-acetylpentandioic acid (APDA) and 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA)) correlated significantly with each other in the 24 hr PM2.5 aerosol samples, indicating that OH· is the major factor controlling the formation of these α-pinene SOA tracers. Using the positive matrix factorization (PMF) model and the tracer-based source apportionment method, we calculated that isoprene oxidation products, α-pinene oxidation products, sesquiterpene oxidation products, biomass burning, fungi spores and anthropogenic SOA accounted for 21.9% ± 5.5%, 8.4% ± 2.1%, 3.0% ± 0.7%, 5.2% ± 5.3%, 5.0% ± 6.2% and 31.4% ± 7.8% of organic carbon respectively during the sampling period.
