Relationships among personal, indoor, and outdoor fine and coarse particleconcentrations for individuals with COPD

This study characterizes the personal, indoor. and outdoor PM2.5. PM10, and PM2.5-10 exposures of 18 individuals with chronic obstructive pulmonary di sease (COPD) living in Boston, MA. Monitoring was performed for each partic ipant for six consecutive days in the winters of 1996 or 1997 and for six t o twelve days in the summer of 1996. On each day, 12-h personal, indoor, an d outdoor samples of PM2.5 and PM10 were collected simultaneously. Home cha racteristic information and time-activity patterns were also obtained. Pers onal exposures were higher than corresponding indoor and outdoor concentrat ions for all particle measures and for all seasons, except for winter indoo r PM2.5-10 levels, which were higher than personal and outdoor levels. High er personal exposures may be due to the proximity of the individuals to par ticle sources, such as cooking and cleaning. Indoor concentrations were ass ociated with both outdoor concentrations and personal exposures las determi ned by individual least square regression analyses), with associations stro ngest for PM2.5. Indoor PM2.5 concentrations were significantly associated with outdoor and personal levels for 12 and 15 of the 17 individuals, respe ctively. Both the strength and magnitude of the associations varied by indi vidual. Also, personal PM2.5, but not PM2.5-10, exposures were associated w ith outdoor levels, with 10 of the 17 subjects having significant associati ons. The strength of the personal-outdoor association for PM2.5, was strong ly related to that for indoor and outdoor levels, suggesting that home char acteristics and indoor particulate sources were key determinants of the per sonal-outdoor association for PM2.5. Air exchange rates were found to be im portant determinants of both indoor and personal levels. Again, substantial interpersonal variability in the personal-outdoor relationship was found, as personal exposures varied by as much as 200% for a given outdoor level.