الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The recent epidemiologic studies evaluated report consistent positive associations between short-term exposure to PM2.5 and respiratory ED visits and hospital admissions for chronic obstructive pulmonary disease (COPD) and respiratory infections. Positive associations were also observed for asthma ED visits and hospital admissions for adults and children combine, but effect estimates are imprecise and not consistently positive for children alone. Most studies reported effects in the range of ” " ~ " ”1% to 4% increase in respiratory hospital admissions and ED visits and were observed in study locations with mean 24-h avg PM2.5 concentrations ranging from 6.1 - 2 μg/m3. Additionally, multicity epidemiologic studies reported consistent positive associations between short-term exposure to PM2.5 and respiratory mortality as well as regional and seasonal variability in risk estimates. The multicity studies evaluated reported consistent,precise increases in respiratory mortality ranging from 1.67 to 2.20% in study locations with mean 24-h avg PM2.5 concentrations above 12.8 μg/m3. Evidence for PM2.5 -related respiratory effects was also observed in panel studies, which indicate associations with respiratory symptoms, pulmonary function, and pulmonary inflammation among asthmatic children. Although not consistently observed, some controlled human exposure studies have reported small decrements in various measures of pulmonary function following controlled exposures to PM2.5. Collectively, the epidemiologic, controlled human exposure, and toxicological studies evaluated demonstrate a wide range of respiratory responses, and although results are not fully consistent and coherent across studies the evidence is sufficient to conclude that a causal relationship is likely to exist between short-term exposures to PM2.5 and respiratory effects.