The formation of SOA and sulfate aerosols from the photooxidation of gasoline vehicle exhaust (GVE) when mixing with SO2
was investigated in a smog chamber. We found that the presence of GVE enhanced the conversion of SO2
to sulfate predominantly through reactions with stabilized Criegee intermediates. On the other hand, the elevated particle acidity enhanced the SOA production from GVE. This study indicated that SO2
and GVE could enhance each other in forming secondary aerosols.