Secondary organic aerosol formation from the ozonolysis and oh-photooxidation of 2,5-dimethylfuran

Abstract

In this study, the O3 and OH radical oxidation of 2,5-dimethylfuran (2,5-DMF) were investigated in two different chambers at (296±1) K and atmospheric pressure to examine secondary organic aerosol (SOA) formation. Results for OH-photooxidation indicate that SOA yieldsdecrease (from 6.2 to 0.4) with the rise of 2,5-DMF concentration (from10 to 1000 ppb). In the absence of NOx and under high relative humidity (RH) conditions (60%), higher aerosol yields are favoured. SOA formation is dependent on the initial seed surface for two kinds of inorganic seed particles ((NH4)2SO4 and CaCl2), being the effect slightly greater for CaCl2. The ozonolysis only generates particles in the presence of SO2 and the increase of relative humidity from 0 to 15% lowers the particle number and particle mass concentrations. The water-to-SO2 rate constant ratio of the Criegee intermediate was derived from the SOA yield in experiments with different relative humidity values, with kH2O/kSO2 = (1.6±0.4)x10−5.