Application of bleach solution (major component NaOCl) in indoor environments emits gaseous hypochlorous acid (HOCl) and chlorine (Cl2), both of which are strong oxidants. In contrast to the outdoor atmosphere, where mixing ratios of HOCl and Cl2 in marine air are low (10s-100s of pptv), indoor HOCl and Cl2 can reach high levels during cleaning activities (100s of ppbv or higher). HOCl and Cl2 may react with unsaturated organic compounds on indoor surfaces and in indoor air. In this study, we studied the reaction of limonene, one of the most common indoor volatile organic compounds (VOCs) arising from use of cleaning products, fragrance, air fresheners, with HOCl and Cl2 in the dark and under indoor irradiation conditions in an environmental smog chamber. A dark reaction was observed between limonene and HOCl/Cl2. The gas-phase reaction products were investigated using proton transfer reaction - mass spectrometry (PTR-MS). With subsequent exposure to indoor fluorescent lights or diffuse sunlight through windows, a significant mass loading of secondary particles formed. Aerosol mass spectrometry (AMS) measurements indicate a large contribution of particulate chlorine species. Electrospray ionization mass spectrometry (ESI-MS) analysis of filter-collected particles indicates formation of high molecular products. This is the first study on the oxidation of limonene with HOCl and Cl2 and of the particle formation under typical indoor lights that may occur in indoor environments due to the use of common cleaning products.

Reaction of limonene with HOCl and Cl2 in the dark followed by particle formation under indoor irradiation conditions

2019 Fall National Meeting

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