Potential for Ion-induced Nucleation of Volatile Organic Compounds by Radon Decay in Indoor Environments

Abstract

The theoretical potential for the formation of clusters of vapor-phase organic compounds found in indoor air around the ²¹⁸PoO_x ⁺ ion was investigated as well as which compounds were most likely to form clusters. A compilation of measurements of indoor organic compounds has been made for future experiments and theoretical calculations by the radon research community. Forty-four volatile and semivolatile organic compounds out of the more than 300 that have been reported in indoor air were investigated. Water vapor was included for comparison. The results indicate that there is a potential for the formation of clusters of organic compounds around the ²¹⁸PoO_x ⁺ ion. The compounds with the greatest potential for cluster formation are the volatile oxidized hydrocarbons (e.g., n-butanol, phenol, hexanal, nonanal, benzaldehyde, the ketones, and the acetates) and the semivolatile organic compounds (pentachlorophenol, nicotine, chlordane, chlorpyrifos). Although the estimated diameters are consistent with the measured diameters for the “unattached” fraction, the state of experimental and theoretical knowledge in this area is not sufficiently developed to judge the quantitative validity of these predictions.