Physical parameters effect on ozone-initiated formation of indoor secondary organic aerosols with emissions from cleaning products

The effect of air exchange rate (ACH), temperature (T), and relative humidity (RH) on the formation of indoor secondary organic aerosols (SOAs) through ozonolysis of biogenic organic compounds (BVOCs) emitted from floor cleaner was investigated in this study. The total particle count (with D_p of 6-225nm) was up to 1.2×10³#cm^-3 with ACH of 1.08h^-1, and it became much more significant with ACH of 0.36h^-1 (1.1×10⁴#cm^-3). This suggests that a higher ventilation rate can effectively dilute indoor BVOCs, resulting in a less ultrafine particle formation. The total particle count increased when temperature changed from 15 to 23°C but it decreased when the temperature further increased to 30°C. It could be explained that high temperature restrained the condensation of formed semi-volatile compounds resulting in low yields of SOAs. When the RH was at 50% and 80%, SOA formation (1.1-1.2×10⁴#cm^-3) was the more efficient compared with that at RH of 30% (5.9×10³#cm^-3), suggesting higher RH facilitating the initial nucleation processes. Oxidation generated secondary carbonyl compounds were also quantified. Acetone was the most abundant carbonyl compound. The formation mechanisms of formaldehyde and acetone were proposed.