Rate Constants for the Gas-Phase Reactions of Ozone and Nitrate Radicals with the Sesquiterpenes: Valencene and Farnesol


  • Jason E. Ham

    Corresponding author
    • Exposure Assessment Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV
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  • The finding and conclusions in this report are those of the author(s) and do not necessarily represent the views of the Centers for Disease Control and Prevention/the Agency for Toxic Substances and Disease Registry.

  • This article is a US Government work and, as such, is in the public domain of the United States of America.

Correspondence to: Jason E. Ham; e-mail: bvo2@cdc.gov.


Sesquiterpenes are constituents of a variety of essential oils that are used in flavorings, perfumes, personal care, and cleaning products. Two sesquiterpenes that are commonly used as indoor fragrances are valencene and farnesol. Knowing the reaction rate constants of these chemicals with ozone (O3) and nitrate radical (inline image) is an important factor in determining their fate indoors. In this study, the bimolecular rate constants of inline image, inline image, inline image, and inline image were measured using the relative rate technique at 297 ± 3 K and 1 atm total pressure. Using the rate constants reported here and measured/modeled indoor concentrations of O3 and inline image (20 ppb and 1 ppt, respectively), pseudo–first-order-rate lifetimes inline image, inline image, inline image, and inline image were determined.