The 1998 Baltimore Particulate Matter Epidemiology-Exposure Study: part 2. Personal exposure assessment associated with an elderly study population.

An integrated epidemiological-exposure panel study was conducted during the summer of 1998 which focused upon establishing relationships between potential human exposures to particulate matter (PM) and related co-pollutants with detectable health effects. The study design incorporated repeated individual 24-h integrated PM2.5 personal exposure monitoring. A total of 325 PM2.5 personal exposure samples were obtained during a 28-day study period using a subject pool of 21 elderly (65+ years of age) residents of an 18-story retirement facility near Baltimore, Maryland. Each sample represented a unique 24-h breathing zone measurement of PM2.5 mass concentration. PM2.5 and PM10 mass concentrations collected from the apartments of the subjects as well as residential and ambient sites were compared to individual and mean PM2.5 personal exposures. Daily PM2.5 personal exposure concentrations ranged from 2.4 to 47.8 microg/m3 with an overall individual study mean of 12.9 microg/m3. Mean PM2.5 personal exposures were determined to be highly correlated to those representing the central indoor (r=0.90) and ambient sites (r=0.89). Subjects reported spending an average of 92% of each day within the confines of the retirement center. Based upon measured and modeled exposures, a mean PM2.5 personal cloud of 3.1 microg/m3 was estimated. Data collected from these participants may be unique with respect to the general elderly population due to the communal lifestyle within the facility and reported low frequency of exposure to sources of PM.