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Formation of Strong Airway Irritants in Terpene/Ozone Mixtures
Author(s) -
WOLKOFF* P.,
CLAUSEN P. A.,
WILKINS C. K.,
NIELSEN G. D.
Publication year - 2000
Publication title -
indoor air
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.387
H-Index - 99
eISSN - 1600-0668
pISSN - 0905-6947
DOI - 10.1034/j.1600-0668.2000.010002082.x
Subject(s) - chemistry , isoprene , terpene , methacrolein , ozone , acrolein , irritation , environmental chemistry , limonene , indoor air quality , formaldehyde , organic chemistry , toxicology , chromatography , environmental engineering , environmental science , monomer , essential oil , immunology , copolymer , catalysis , biology , methacrylic acid , polymer
The American Society for Testing and Materials (ASTM) mouse bioassay, which quantifies airway irritation from reduction in the respiratory rate, was used to find evidence for the formation of highly irritating substances in reactions of ozone with terpenes (common indoor volatile organic compounds (VOCs)). No‐observed‐effect‐levels (NOELs) and concentration‐effect relationships were established for ozone, (+)‐α‐pinene and R‐(+)‐limonene, isoprene, and some of their major reaction products. Reaction mixtures of excess terpene and ozone considerably below their NOEL concentrations resulted in significant upper airway irritation. The reduction of the respiratory rate was from 30% to about 50%, lowest for the α‐pinene and highest for the isoprene mixture. Chemical analysis of reaction mixtures by conventional methods showed that readily identified stable products and residual reactants at the concentrations found could not account for the observed reductions of the respiratory rate, assuming additivity of the reaction products. The results suggest that, in addition to known irritants (formaldehyde, acrolein, methacrolein, methyl vinylketone), one or more strong airway irritant(s) of unknown structure(s) were formed. Future indoor air quality (IAQ) guidelines for unsaturated VOCs (e.g., terpenes) and their emission from building products may require the consideration of reactions with oxidants, like ozone. Similarly, effects of ozone‐emitting equipment should be re‐evaluated. NOTE