Chemical Kinetics of a Monoterpene with Ozone on a Model Indoor Surface


The objective of this research is to quantify surface reaction rates of ozone with Δ3-carene on model indoor surfaces. The monoterpene Δ3-carene is commonly used in cleaners and other consumer products, and its reaction with ozone generates toxic products, including formaldehyde. To assess surface reaction kinetics, a diluted stream of Δ3-carene is introduced into a plug flow reactor filled with small beads that act as model surfaces. First, adsorption is quantified in the form of molar surface loading, by performing breakthrough experiments with the monoterpene in the absence of ozone. Second, the diluted monoterpene is introduced into the plug flow reactor along with ozone, and the amount of ozone consumed (with and without the terpene) is quantified. The ozone uptake rate is combined with adsorption information to determine a pseudo-first order reaction rate coefficient and ultimately an ozone-terpene reaction probability. To mimic typical indoor conditions, the temperature is varied from 20 to 30ºC and the relative humidity is varied from 10% to 80%. In this paper, the results for the reaction of ozone with Δ3-carene on glass are reported. We show for the first time that ozone reacts with Δ3-carene on this surface and that the ozone-terpene reaction probability ranges from approximately 3.0 × 10-6 to 2.5 × 10-5. These reaction probabilities are 10 to 80 times higher than that estimated for the gas-phase reaction. Thus, glass enhances (i.e. catalytically) ozone-terpene reaction rates.


Civil, Architectural and Environmental Engineering

Keywords and Phrases

Cleaners; Consumer Products; Formaldehyde; Indoor Surfaces; Ozone; Reaction Kinetics

Document Type

Article - Conference proceedings

Document Version


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