Relationship between Acute Ozone Responsiveness and Chronic Loss of Lung Function in Residents of a High-Ozone Community

Abstract

We hypothesized that acute respiratory responsiveness to ozone predicts chronic lung injury from repeated exposure to ozone-containing air pollution. We tested this hypothesis in 164 middle-aged nonsmoking residents of an ozone-polluted community who underwent lung-function measurements during 1986 and 1987 (i.e., time 3). The time-3 study was a follow up of more comprehensive studies conducted in 1977–1978 (time 1) and in 1982–1983 (time 2). In contrast to the apparent rapid (i.e., = 60 ml/y) decline in lung-function measurements between times 1 and 2, our subjects showed little change in forced vital capacity (FVC) or forced expired volume in 1 s (FEV_1.0) between times 2 and 3, and they experienced a normal decline between times 1 and 3. A subgroup (n = 45) underwent 2-h laboratory ozone exposures to 0.4 ppm ozone, accompanied by intermittent exercise, and they experienced mild acute reductions in FEV_1.0 and FVC, but there was little change in bronchial responsiveness to methacholine. Individual acute responses to laboratory ozone were not correlated with individual long-term changes between times 1 and 3. In summary, the results did not support our initial hypothesis, and they did not confirm rapid function decline in nonsmokers chronically exposed to ozone-containing air pollution.