Gas–particle partitioning of polyol tracers at a suburban site in Nanjing, east China: increased partitioning to the particle phase

Abstract. Gas–particle partitioning of water-soluble organic compounds plays a significant role in influencing the formation, transport, and lifetime aerosols atmosphere, but is poorly characterized. In this work, gas- particle-phase concentrations isoprene oxidation products (C5-alkene triols 2-methylterols), levoglucosan, sugar polyols were measured simultaneously at suburban site western Yangtze River Delta east China. All target primarily distributed into particle phase (85.9 %–99.8 %). Given uncertainties measurements vapor pressure predictions, dependence fractions on pressures cannot be determined. To explore impact aerosol liquid water gas–particle polyol tracers, three schemes (Cases 1–3) proposed based equilibriums gas vs. aqueous phases aerosols. If particulate matter (OM) presumed as only absorbing (Case 1), measurement-based absorptive coefficients (Kp,OMm) levoglucosan more than 10 times greater predicted values (Kp,OMt). The agreement between Kp,OMm Kp,OMt was substantially improved when solubility separate included, whenever water-insoluble OM partitioned 2) or single 3) phases, suggesting that tracers should not ignored. effective Henry's law (KH,em) orders magnitude higher their pure (KH,wt). Due to moderate correlations log?(KH,em/KH,wt) molality sulfate ions, gap KH,em KH,wt could fully parameterized by equation defining “salting-in” effects might ascribed mechanisms reactive uptake, reaction, “like-dissolves-like” principle, etc. These study results also partly reveal discrepancy observation modeling