Ozone & Oxidants

This report describes the first-ever multicity study to estimate the effect of short-term exposures to particulate matter (PM₁₀) and to ozone on mortality in nine Latin American cities. Led by Dr. Isabelle Romieu in Mexico, in collaboration with Dr. Nelson Gouveia in Brazil and Dr. Luis Cifuentes in Chile, the researchers evaluated mortality from all causes and in different age groups, using a common analytic framework. They analyzed mortality in each city and the region as a whole, and explored two pollutant models in individual cities. They also used two meta-analytic statistical techniques to further analyze the effects from individual cities.

This report is the latest in HEI's program of studies to assess the health impacts of air quality actions. Research Report 148 describes a study to evaluate the effect of a short-term, temporary intervention to reduce traffic congestion during the 1996 Summer Olympic Games in Atlanta, Georgia. A previous study had shown a decrease in acute care visits for pediatric asthma and a concomitant decrease in concentrations of ozone, particulate matter, and carbon monoxide.

The September issue of Environmental Health Perspectives published the first systematic presentation of the HEI-funded PAPA studies in Bangkok, Hong Kong, Shanghai, and Wuhan, as well as a combined analysis and accompanying editorial. These articles have been reprinted and are currently available as HEI Communication 13. The detailed studies and accompanying HEI commentaries will be published by the Institute this spring.

Dr James Ultman and colleagues at Pennsylvania State University recruited 32 men and 28 women to examine differences in ozone uptake in the lung. The subjects (all non smokers) first took a series of single breaths of air–ozone mixtures, which allowed the investigators to examine how ozone was distributed in the airways and where the major fraction of ozone was taken up. In a follow-up test, the subjects pedaled a bicycle ergometer to produce conditions of moderate exercise for one hour while breathing clean air, followed by a third test while breathing ozone at 0.25 ppm).

Dr. Lester Kobzik and colleagues at the Harvard School of Public Health used a mouse model of asthma to evaluate how inhaling pollutants affects the airways. The mice were sensitized to the allergen ovalbumin, which induces a lung condition in the mice similar to that found in people with asthma. The investigators hypothesized that exposure to concentrated ambient particles (CAPs) plus ozone would cause a synergistic (or greater-than-additive) response in the mice.