Polar organic tracers in PM 2.5 aerosols from an inland background area in Southwest China: Correlations between secondary organic aerosol tracers and source apportionment

Molecular Characteristics and Formation Mechanisms of Biogenic Secondary Organic Aerosols in the Summer Atmosphere at Mt. Tai on the North China Plain

“…Hua and Mt. Gongga, China (Li et al, 2013a;Li et al, 2018a). The concentration of β-caryophyllinic acid was comparable to those measured in Mt.…”

Secondary organic aerosol tracers and related polar organic compounds between urban and rural areas in the Eastern Mediterranean region: source apportionment and the influence of atmospheric oxidants

“…This can be further supported by the calculated SOC which contributes to a signicant portion of the total OC (46.8 AE 15.3%). Particularly, SOC mean concentration was 0.91 AE 0.41 mg m À3 which, compared with SOC from other studies, calculated with the same method, is lower than that in Toulouse (3.04 mg m À3 and 65.85% of OC, during summer), 68 and than 2.9 AE 3.4 mg m À3 in Gongga Mountain, China, 19 while being at the same levels as in Brindisi, Italy (1.9 AE 2.2 mg m À3 ). 55 The daily variations of PM, OC, EC and SOC are presented in Fig.…”

“…This method for SOC estimation has already been used in many rural/background and urban locations. 19,54,55…”

“…62 In AGM OC presented a mean concentration of 1.9 AE 0.45 mg m À3 which is quite higher than that measured in Azores, Portugal (0.33 AE 0.26) and Sonnblick, Austria (0.90 AE 1.0), 63 but lower than 2.85 AE 1.63 mg m À3 measured in an urbanbackground site in Patra, Greece, 64 and also lower than 3.5 AE 2.8 mg m À3 in a rural site in Brindisi, Italy 55 and than 3.8 AE 3.7 mg m À3 found in Gongga Mountain, China. 19 The average OC/EC ratio, in AGM, was 11.0 AE 3.3 which is nearly ten times higher than the ratio calculated in Thessaloniki (1.9 AE 1.4), an urban area of Eastern Mediterranean, 65 and also higher than that at two urban-background Greek sites in Thessaloniki and Patra (8.1 and 7.5, respectively) 64,65 but lower than those reported in Azores (13.5 AE 17.4). 63 In general, the OC/EC ratio can be used to characterize the relative contribution of secondary versus primary sources, with values > 2 being indicative of signicant SOA contributions.…”

“…11,15,16 SOAs are a remarkable component of atmospheric ne particles constituting a large to dominant (20-80%) percentage of their total organic mass; 17 hence a comprehensive understanding of SOA formation mechanisms under different atmospheric conditions is essential. 18,19 SOA marker compounds generally contain one or more oxygenated functional groups including hydroxyl (OH), carboxyl (HOC]O) and carbonyl (C]O) groups, making them highly polar. 11 SOAs have direct effects on climate as they can absorb and scatter solar radiation and indirect effects as they affect the cloud condensation nuclei (CCN) particles either by forming new particles or by growing the preexisting ones.…”