Impacts of Semivolatile Organic Carbons and Relative Humidity on the Deposition Rate of Ozone to Permeable Indoor Surfaces
JILLIAN DOWNEY, Jonathan Abbatt,
University of Toronto Abstract Number: 114
Working Group: Indoor Aerosols
AbstractOzone (O
3) reacts with unsaturated compounds, whose reaction products, when inhaled, can result in negative health effects. For many unsaturated molecules, the surface reactivity is over 100 times that in the gas phase. Given that indoor environments have a much higher surface area-to-volume ratio compared to outdoor environments, surface reactions play a huge role in establishing indoor air quality. O
3 loss rates on single-component, clean surfaces have been well studied. However, the indoor environment is complex, with many surfaces being permeable and/or covered in semivolatile organic carbons (SVOCs). Diffusion rates of O
3 into permeable surfaces depend on relative humidity (RH), and the partitioning of SVOCs may also be affected by RH. This suggests that RH will affect O
3 reactivity, however, an understanding of these processes is limited. This work addresses how O
3 deposition on a permeable surface (painted surface) is affected by a model unsaturated SVOC (terpineol) at different RHs. Firstly, to quantify O
3 deposition on a painted surface, O
3 was passed through a chamber (with painted surfaces on the top and bottom) and O
3 was monitored at varying RHs. Then, terpineol uptake on a painted surface was quantified by measuring the sorbed mass of terpineol using an online mass spectrometer at different RHs. Lastly, O
3-terpineol reactivity at varying RHs was studied, where O
3 was introduced to a terpineol-conditioned chamber. It was found that increased RH increases O
3 deposition and terpineol partitioning into the paint. Also, the presence of terpineol increases ozone deposition, emphasizing the importance of SVOC-O
3 surface reactions on indoor air quality.