Exposure of chronic obstructive pulmonary disease patients to particulate air pollution : an assessment of respiratory health effects

Epidemiological studies suggest associations between particulate air pollution and health effects, including decreased lung function, and increased respiratory symptoms and medication use. Studies also suggest that persons with cardiopulmonary disease may be at increased risk for particle-related health effects. This study measured personal and ambient fine particulate (PM₂.₅) and sulfate concentrations for chronic obstructive pulmonary disease (COPD) patients, and evaluated the relationships between exposure and lung function, respiratory symptoms, and medication use. This study was conducted during the summer of 1998 in the Greater Vancouver Regional District, British Columbia. Sixteen (7 male, 9 female) non-smoking COPD patients (mean age: 74, range: 54-86) were recruited from the Vancouver Hospital Respiratory Clinic (13) and B.C. Lung Association (3). Each subject was equipped with a PM₂.₅ monitor, activity diary, and medication log for seven 24-hour periods (approximately 1.5 weeks apart). Before and after sampling periods, subjects performed forced expiratory maneuvers using portable spirometers. Following sampling periods, subjects completed symptom questionnaire interviews. Ambient PM₂.₅ measurements were obtained on days corresponding to personal sampling at 5 sites within the study area. All samples were analyzed for PM₂.₅ mass and sulfate concentrations. Mean personal and ambient PM₂.₅ (and sulfate) levels were 18 and 11 (1.5 and 1.9) μg/m³, respectively. No associations between air pollution and respiratory health outcomes were statistically significant. However, weighted regression analyses suggest that up to a 1% decline in FEVi may be associated with each 10 pg/m3 increase in ambient PM₂.₅ , and 0.27- 1.04% declines in FEVi may be associated with each μg/m³ increase in personal and ambient sulfate. These associations were not observed with respect to personal PM₂.₅ exposure, suggesting that ambient PM₂.₅, personal sulfate, and ambient sulfate were more strongly associated with adverse health effects than was personal PM₂.₅. Ozone also appeared to be associated with decreased FEVi. Consequently, it was not possible to differentiate between the effects of particulates and ozone. No consistent associations were observed between any exposure measure and symptom severity or bronchodilator use. Major limitations of this study included the small degree of variability in exposure, and the quality of symptom questionnaire and bronchodilator use data.Medicine, Faculty ofMedicine, Department ofExperimental Medicine, Division ofGraduat