Hydrogen Peroxide Emission and Fate Indoors during Non-bleach Cleaning: A Chamber and Modeling Study

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 o 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.