In an open-top chamber study in east Texas, ozone-sensitive loblolly pine (Pinus taedu L.) seedlings were treated with either the antioxidant Ozoban (74.5% sodium erythorbate active ingredient (a.i.)) at 0, 1030, or 2060 mg liter-’ or ethylenediurea (EDU 50% a.i.) at 0, 150, or 300 ppm every 2 weeks while being subjected to a range of ozone exposures beginning in April 1994. The ozone exposures...

Exposure to particulate matter and ozone cause adverse airway reactions. Individual pollutant effects are often addressed separately, despite coexisting in ambient air. The present investigation was performed to study the effects of sequential exposures to diesel exhaust (DE) and ozone on airway inflammation in human subjects. Healthy subjects underwent bronchoscopy with bronchoalveolar lavage ...

Nitrogen (N) deposition in the western United States is most severe near major urban areas or downwind of agricultural regions, particularly in areas where confined animal feeding operations such as dairies or feedlots are located. Nitrogen saturated ecosystems are predominantly found in hotspots located within 60 km of urban or agricultural emissions source areas, where N deposition inputs are...

During the first ten years of the SOS program, the major focus in research was on regional oxidant (especially ozone) pollution and the earliest objectives were to identify ozone-related chemical and meteorological factors that were unique to the SOS region – such as the large quantities of biogenic VOC emissions, greater frequencies of air stagnation days, and abundant NOx-producing lightning ...

During the first ten years of the SOS program, the major focus in research was on regional oxidant (especially ozone) pollution and the earliest objectives were to identify ozone-related chemical and meteorological factors that were unique to the SOS region – such as the large quantities of biogenic VOC emissions, greater frequencies of air stagnation days, and abundant NOx-producing lightning ...

The Clean Air Act requires that sensitive subgroups of exposed populations be protected from adverse health effects of air pollution exposure. Hence, data suggesting the existence of sensitive subgroups can have an important impact on regulatory decisions. Some investigators have interpreted differences among individuals in observed pulmonary function response to air pollution episodes as evide...

Epidemiological evidence suggests that exposure to ozone increases cardiovascular morbidity. However, the specific biological mechanisms mediating ozone-associated cardiovascular effects are unknown. To determine whether short-term exposure to ambient levels of ozone causes changes in biomarkers of cardiovascular disease including heart rate variability (HRV), systemic inflammation, and coagula...

Of the outdoor air pollutants regulated by the Clean Air Act of 1970 (and recently revised in 1990), ozone has been the one pollutant most difficult to control within the federal standards. The known human health effects are all on the respiratory system. At concentrations of ozone which occur during summer air-pollution episodes in many urban metropolitan areas of the United States, a portion ...

To study whether the individual inflammatory response to ozone was reproducible, dose-dependent, and time-dependent, we performed two exposures to 250 ppb ozone, one to 125 ppb and one to filtered air, each for 3 h of intermittent exercise and separated by at least 1 wk. Twenty-one healthy and 15 asthmatic subjects participated in the study. One hour after the two exposures to 250 ppb ozone we ...

Ozone measurements (daily maximum values) from the Aerometric Information Retrieval System database are analyzed for selected sites, during 1980 to 1988, in southeastern USA. Frequency distributions, for most sites during most years, show a typical bell-shaped curve with the higher frequency around the yearly daily maximum ozone mean of about 100 to about 110 microg m(-3) (50-55 ppbv). Abnormal...