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Kephalopoulos S., et al
Bibliographic info:
EUR 23052 - European Collaborative Action: Urban Air, Indoor Environment and Human Exposure - Environment and Quality of Life

Hundreds of compounds have been measured in indoor air includingVOCs (volatile organic compounds), NOX (nitrogen oxides) and ozone (O3). However, to date, the only potential sensory irritants to be identified has been formaldehyde. Until recently, most research has focussed on the compounds that are emitted indoors and relatively little attention has been paid to the significance of the reactions that are likely to occur between them, i.e. mixtures. Furthermore, it is unclear whether the concentrations observed indoors are detrimental to health, or even if the compounds that are detrimental to health are being measured. For instance, hitherto unmeasured compounds have recently been confirmed to be present in abundant amounts at ambient conditions through the reactions of ozone and terpenes. Recent work suggests that the products of VOC degradation (oxidation), in particular those of terpenes, following reaction with O3, the OH or NO3 radicals,may be responsible for some of the reported symptoms.When ozone reacts with these VOCs, radicals such as OH, HO2 and RO2 are formed, as well as stable products such as aldehydes, peroxides and condensed phase compounds, some of which are sensory eye and airway irritants. Many of these compounds cannot currently be measured by traditional analytical techniques.
In this report an attempt has been made to summarise the state of the art concerning ozone-initiated chemistry and its impact on indoor air quality and human health and to prioritise research goals for the future. The focus of this report is on terpenes (e.g., limonene, α-pinene), owing to their high chemical reactivity and abundance in the indoor environment.