Hydrogen Peroxide Emission and Fate Indoors during Non-bleach Cleaning: A Chamber and Modeling Study
Shan Zhou, Zhenlei Liu, Zixu Wang, Cora J. Young, Trevor C. VandenBoer, Bing Guo, Jianshun Zhang, Nicola Carslaw, Tara F. Kahan
Abstract
Activities such as household cleaning can greatly alter the composition of air in indoor environments. We continuously monitored hydrogen peroxide (H 2 O 2 ) from household non-bleach surface cleaning in a chamber designed to simulate a residential room. Mixing ratios of up to 610 ppbv gaseous H 2 O 2 were observed following cleaning, orders of magnitude higher than background levels (sub-ppbv). Gaseous H 2 O 2 levels decreased rapidly and irreversibly, with removal rate constants ( k H 2 O 2 ) 17–73 times larger than air change rate (ACR). Increasing the surface-area-to-volume ratio within the room caused peak H 2 O 2 mixing ratios to decrease and k H 2 O 2 to increase, suggesting that surface uptake dominated H 2 O 2 loss. Volatile organic compound (VOC) levels increased rapidly after cleaning and then decreased with removal rate constants 1.2–7.2 times larger than ACR, indicating loss due to surface partitioning and/or chemical reactions. We predicted photochemical radical production rates and steady-state concentrations in the simulated room using a detailed chemical model for indoor air (the INDCM). Model results suggest that, following cleaning, H 2 O 2 photolysis increased OH concentrations by 10–40% to 9.7 × 10 5 molec cm –3 and hydroperoxy radical (HO 2 ) concentrations by 50–70% to 2.3 × 10 7 molec cm –3 depending on the cleaning method and lighting conditions.