MEASUREMENT OF ORGANIC-ACIDS, ALDEHYDES, AND KETONES IN RESIDENTIAL ENVIRONMENTS AND THEIR RELATION TO OZONE

Ozone and several polar volatile organic compounds (VOCs) including or ganic acids and carbonyls (aldehydes and ketones) were measured over a n approximately 24 hour period in four residences during the winter of 1993 and in nine residences during the summer of 1993. All residences were in the greater Boston, Massachusetts area. The relation of the p olar VOCs to the ozone concentration was examined. Indoor carbonyl con centrations were similar between the summer and winter, with the total mean winter concentration being 31.7 ppb and the total mean summer co ncentration being 36.6 ppb. However, the average air exchange rate was 0.9 hr(-1) during the winter and 2.6 hr(-1) during the summer. Theref ore, the estimated carbonyl emission rates were significantly higher d uring the summer. Indoor organic acid concentrations were about twice as high during the summer as during the winter. For formic acid, the i ndoor winter mean was 9.8 ppb, and the summer indoor mean was 17.8 ppb . For acetic acid, the indoor winter mean was 15.5 ppb, and the summer indoor mean was 28.7 ppb. The concentrations of the polar VOCs were f ound to be significantly correlated with one another. Also, the emissi on rates of the polar VOCs were found to be correlated with both the e nvironmental variables such as temperature and relative humidity and t he ozone removal rate; however, it was difficult to apportion the rela tive effects of the environmental variables and the ozone removal.