Research Program Area: Health & Exposure
Health effects of ozone exposure under conditions simulating ambient photochemical pollution episodes have been investigated in volunteer subjects known or suspected to be hyper reactive to inhaled irritant substances. Twenty-five individuals were exposed to approximately 0.2 ppm 03 and/or approximately 0.4 ppm 03. Six of these were clinical asthmatics; the others had histories of one or more of the following: rare asthmatic symptoms, upper-respiratory allergy, subjective respiratory sensitivity to photochemical pollution exposure, mild obstructive pulmonary-function abnormality.
The group exposed to 0.4 ppm showed small but significant (Pc.05) changes in pulmonary function and highly significant (Pc.005) increases in respiratory symptoms (expressed as a semi quantitative score) and changes in blood biochemical measures. The group exposed to 0.2 ppm showed significant blood biochemical changes (P < .O5), but no significant changes in symptoms or pulmonary function. Two asthmatic individuals did, however, develop exposure related symptoms and function changes at 0.2 ppm. These results suggest that at least some asthmatics are markedly more sensitive to 03 than normal and may suffer noticeable health effects at concentrations near 0.2 ppm.
Most non asthmatic Los Angeles residents tested tolerate exposure to 0.4 ppm, but some non residents react severely to 0.4 ppm, suggesting that adaptation to chronic ambient oxidant exposure develops in relatively healthy Los Angeles residents.
This report was submitted in fulfillment of Contract No. 4-191 by Professional Staff Association of Rancho Los Amigos Hospital, Inc., under sponsorship of the California Air Resources Board. Work was completed 1 December 1975.
For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753
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