Ozone & Oxidants

Ozone is a highly reactive gas that is a pervasive air pollutant at ground level. It is a major component of urban smog, forming when emissions from mobile and industrial sources interact with sunlight. When inhaled, ozone can cause cough, shortness of breath, and transient changes in breathing patterns; however the health significance of these effects is unknown. Dr. Philip Bromberg and coworkers at the University of North Carolina, Chapel Hill examined whether exposure to ozone alters properties of the airway epithelium.

This report describes a study by Drs. Ultman and Ben-Jebria to develop a chemiluminescent ozone analyzer and constructed an ozone bolus generator with the goal of using bolus concentration-response methods to noninvasively measure the longitudinal distribution of ozone absorption in human lungs. The analyzer was based on the chemiluminescent reaction between 2-methyl-2-butene and ozone. Validation of the system was performed in excised pig and sheep tracheas, and the resulting absorption coefficient was computed.

This report addressed the hypothesis that hypertrophy of the lung after oxidant injury with ozone or oxygen is due to local generation of lung-specific growth factors. Dr. Tanswell exposed rats to either 85% oxygen, 1 ppm ozone, or air for up to two weeks while samples of plasma, lung washings, and lung tissue were periodically collected. These samples were tested for their effect on the DNA synthesis of purified populations of three major lung cell types (pneumocyte, fibroblast, and endothelial cell) in culture.

Addressing the need for better assessment of human exposure to mobile source emissions, this report investigates proteinase inhibitor activity as a potential biomarker of oxidant exposure. In this study by Dr. Johnson, human participants were exposed to 0.5 ppm ozone for four hours on consecutive days and to concentrations ranging from 0.6-2 ppm nitrogen dioxide for three hours. Blood samples were obtained and the functional activity of the proteinase inhibitors, alpha-1-proteinase, and bronchial leukocyte proteinase was assessed.