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

Abstract

This study characterizes the personal, indoor, and outdoor PM 2.5 , PM 10 , and PM 2.5 ± 10 exposures of 18 individuals with chronic obstructive pulmonary disease ( COPD ) living in Boston, MA. Monitoring was performed for each participant for six consecutive days in the winters of 1996 or 1997 and for six to twelve days in the summer of 1996. On each day, 12 -h personal, indoor, and outdoor samples of PM 2.5 and PM 10 were collected simultaneously. Home characteristic information and time ± activity patterns were also obtained. Personal exposures were higher than corresponding indoor and outdoor concentrations for all particle measures and for all seasons, except for winter indoor PM 2.5 ± 10 levels, which were higher than personal and outdoor levels. Higher personal exposures may be due to the proximity of the individuals to particle sources, such as cooking and cleaning. Indoor concentrations were associated with both outdoor concentrations and personal exposures ( as determined by individual least square regression analyses ) , with associations strongest for PM 2.5 . Indoor PM 2.5 concentrations were significantly associated with outdoor and personal levels for 12 and 15 of the 17 individuals, respectively. Both the strength and magnitude of the associations varied by individual. Also, personal PM 2.5 , but not PM 2.5 ± 10 , exposures were associated with outdoor levels, with 10 of the 17 subjects having significant associations. The strength of the personal ± outdoor association for PM 2.5 was strongly related to that for indoor and outdoor levels, suggesting that home characteristics and indoor particulate sources were key determinants of the personal ± outdoor association for PM 2.5 . Air exchange rates were found to be important 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.

Estimating effects of ambient PM2.5 exposure on health using PM2.5 component measurements and regression calibration

“…Recently, personal exposure monitors (henceforth called personal monitors) have been used in some air pollution studies to get a better idea of how ambient pollution concentrations relate to personal breathing zone exposures (Janssen et al, 1997(Janssen et al, , 1998(Janssen et al, , 1999Ebelt et al, 2000;Rojas-Bracho et al, 2000;Williams et al, 2000;Liu et al, 2003). Some have argued that moderate to strong correlations between (average) personal 1.…”

Exposure time and place: Do COPD patients differ from the general population?

“…In Boston (Rojas-Bracho et al, 2000, 2004 more time was spent indoors in winter (91%) than in summer (84%) and more time was spent outdoors in summer (7%), than in winter (o1%). Time spent cleaning, especially vacuuming and cooking, affected personal particulate exposures and so these were examined within our larger data set as well.…”

“…The data from these panel studies shows that time indoors at home ranged from 70% (Rojas-Bracho et al, 2000) to 92% (Ebelt et al, 2000). In Boston (Rojas-Bracho et al, 2000, 2004 more time was spent indoors in winter (91%) than in summer (84%) and more time was spent outdoors in summer (7%), than in winter (o1%).…”

“…There are several panel studies examining time-activity data in smaller groups of COPD patients (samples of 12-34 subjects) in relationship to personal particulate exposure measurements (Rojas-Bracho et al, 2000, 2004Sarnat et al, 2000;Allen et al, 2003;Liu et al, 2003). Timeactivity data in these studies usually examined 12 h daytime time-activity diaries, often self-administered, and in conjunction with particulate exposures of which the subjects were aware.…”

“…In personal particulate exposure studies, small panels of COPD patients wearing monitors have also kept timeactivity data logs (Ebelt et al, 2000;Rojas-Bracho et al, 2000, 2004Sarnat et al, 2000;Allen et al, 2003;Liu et al, 2003) but subjects were aware of particulate exposure questions, wore the added weight of the samplers and only nonsmokers could be studied.…”