Effect of ammonia on ozone-initiated formation of indoor secondary products with emissions from cleaning products

Biogenic volatile organic compounds (BVOCs) emitted from cleaning products and air fresheners indoors are prone to oxidation resulting in the formation of secondary pollutants that can pose health risks on residents. Ammonia (NH₃) is ubiquitous in ambient and indoor environments. In this study, we investigated the effect of ammonia (NH₃) on secondary pollutants formation from the ozonolysis of BVOCs emitted from cleaning products including floor cleaner (FC), kitchen cleaner (KC) and dishwashing detergent (DD) in a large environmental chamber. Our results demonstrated that the presence of NH₃ (maximum concentration is 240 ppb) could significantly enhance secondary organic aerosols (SOAs) formation from the ozonolysis of all the three categories of cleaning products. For example, for the FC sample, the maximum total particle concentration was up to 2.0 × 10⁴ # cm^-3 in the presence of NH₃, while it was 1.3 × 10⁴ # cm^-3 which was 35% lower without NH₃. However, it was found that the extent of NH₃ effect on SOAs formation from the ozonolysis of BVOCs emissions was component-dependent. The presence of NH₃ in the reaction systems could increase the consumptions of d-limonene that is the dominant BVOC species as identified in cleaning products. The percent yields (%) of secondary carbonyl compounds generated from the ozonolysis of BVOCs emitted from three categories of cleaning products were identified in the presence and absence of NH₃, respectively. The increase in SOAs particle number concentration can be attributed to the formation of condensable salts from reactions between NH₃ and organic compounds generated from the BVOCs ozonolysis processes. By investigating the NH₃ effect on the ozonolysis of BVOCs mixtures in contrast to the chemistry of individual compounds, a better assessment can be made of the overall impact cleaning products have on real indoor environments.