Exposures of Elderly Volunteers with and without Chronic Obstructive Pulmonary Disease (COPD) to Concentrated Ambient Fine Particulate Pollution
Source: Inhalation Toxicology, Volume 16, Numbers 11-12, Numbers 11-12/2004 , pp. 731-744(14)
Publisher: Informa Healthcare
Abstract:The elderly and individuals who have chronic obstructive pulmonary disease (COPD) may be sensitive to particulate matter (PM) air pollution. We evaluated short-term health responses of 13 elderly volunteers with COPD and 6 age-matched healthy adults to controlled exposures of ambient PM pollution in suburban Los Angeles. Using a Harvard particle concentrator and a whole-body chamber, we exposed each person on separate occasions to approximately 200 μg/m3 concentrated ambient particles (CAP) less than 2.5 μm in diameter and to filtered air (FA). Each exposure lasted 2 h with intermittent mild exercise. We found no significant effects of CAP on symptoms, spirometry, or induced sputum. A significant negative effect of CAP on arterial oxygenation (measured by pulse oximetry) immediately postexposure was more pronounced in healthy subjects. Peripheral blood basophils increased after CAP in healthy but not in COPD subjects. In both groups, red cell counts increased slightly 1 day after exposure to FA but not to CAP. Preexposure ectopic heartbeats were infrequent in healthy subjects, but increased modestly during/after CAP exposure relative to FA. Ectopic beats were more frequent in COPD subjects, but decreased modestly during/after CAP relative to FA. Heart-rate variability over multihour intervals was lower after CAP than after FA in healthy elderly subjects but not in COPD subjects. Thus, in this initial small-scale study of older volunteers experimentally exposed to ambient PM, some acute cardiopulmonary responses were consistent with effects reported from epidemiologic studies. Unexpectedly, individuals with COPD appeared less susceptible than healthy elderly individuals. Further investigation of older adults is warranted to understand the pathophysiology and public health significance of these findings.
Document Type: Research Article
Affiliations: 1: Los Amigos Research and Education Institute, Downey, California, USA 2: Keck School of Medicine, University of Southern California, Los Angeles, California, USA 3: Los Amigos Research, Downey, California, USA 4: School of Engineering, University of Southern California, Los Angeles, California, USA 5: School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA 6: National Health and Environmental Effects Research Laboratory, Environmental Protection Agency, Research Triangle Park, North Carolina, USA
Publication date: January 1, 2004