Effects of exposure to 0.06 ppm ozone on FEV1 in humans: a secondary analysis of existing data.
BACKGROUND
Ozone is a potent photochemical oxidant that produces transient, reversible decrements in the lung function of acutely exposed individuals. A recent study provided previously unavailable clinical data for 30 healthy young adults exposed to O(3) at 0.06 ppm. That study showed significant effects of 0.08 ppm on lung function, confirming the findings of others. However, exposure to 0.06 ppm O(3) was not reported to significantly affect lung function.


OBJECTIVE
We conducted this analysis to reevaluate the existing lung function data of the volunteers previously exposed to 0.06 ppm O(3).


METHODS
We obtained pre- and postexposure data on forced expiratory volume in 1 sec (FEV(1)) for all subjects who were previously exposed for 6.6 hr to filtered air or to 0.06 ppm or 0.08 ppm O(3). We used standard statistical methods appropriate for paired comparisons to reanalyze FEV(1) responses after exposure to 0.06 ppm O(3) relative to filtered air.


RESULTS
Controlling for filtered air responses, 24 of the 30 subjects experienced an O(3)-induced decrement in FEV(1). On average, 0.06 ppm O(3) exposure caused a 2.85% reduction in FEV(1) (p < 0.002), which was consistent with the predicted FEV(1) response from existing models. Although the average response was small, two subjects had > 10% FEV(1) decrements.


CONCLUSIONS
Exposure to 0.06 ppm O(3) causes a biologically small but highly statistically significant decrease in mean FEV(1) responses of young healthy adults.
Brown
James S
JS
National Center for Environmental Assessment, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA. Brown.James@epa.gov
Bateson
Thomas F
TF
McDonnell
William F
WF
D000328:Adult; D000393:Air Pollutants / Q000633:toxicity*; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects*; D006801:Humans; D019570:Inhalation Exposure; D008297:Male; D010126:Ozone / Q000633:toxicity*
D000393:Air Pollutants; D010126:Ozone