Relationship between indoor, outdoor, and personal fine particle concentrations for individuals with COPD and predictors of indoor-outdoor ratio in Mexico city

Personal exposure and indoor and outdoor exposure to PM10 and PM2.5 of 38 individuals with chronic obstructive pulmonary disease (COPD) was characterized from February through November 2000. All participants lived in Mexico City and were selected based on their area of residence southeast (n=15), downtown (n=15), and southwest (n=8). Participants were monitored at home using personal PM2.5 monitoring devices. Indoor and outdoor levels of PM10 and PM2.5 were measured using MiniVol samplers. Concurrent individual exposure measurements, indoor and outdoor levels of PM2.5, which averaged 38.4 (SD 21.4), 30.6 (SD 15.8), and 30.5 μg/m3 (SD 19.4), respectively. Indoor PM2.5 concentrations explained 40% of the variability of personal exposure. In addition, the factors that most affected personal exposure were regular indoor contact with animals, mold, cooking activities, and aerosol use, indicating that internal sources may largely affect individual exposure.