Personal reactive clouds: Introducing the concept of near head chemistry

The "personal cloud" effect and its impact on human exposure to airborne pollutants are well documented. A great deal is also known regarding indoor air chemistry, particularly as related to ozone reactions with mono-terpenes. In this paper we hypothesize the presence of personal reactive clouds that result from ozone reactions with terpenes and terpenoids emitted from many personal care products. A screening assessment was completed based on reaction rates between ozone and four reactive organic compounds that are commonly employed in personal care products. Reaction times (for homogeneous reactions in the breathing zone) were assumed to be on the order of 1s. Screening results suggest the potential for observable decreases in ozone concentration and the subsequent presence of reaction products in the human breathing zone due to near head chemistry.