Personal coarse particulate matter exposures in an adult cohort

Volunteers associated with the North Carolina Adult Asthma and Environment Study (NCAAES) participated in an investigation of personal daily exposures to coarse and fine particulate matter size fractions (PM10–2.5, PM2.5). Data from these personal measurements were then compared to community-based measures that might typically represent surrogate measurements of exposure often used in epidemiological assessments. To determine personal exposures to various particulate matter (PM) size fractions, a recently evaluated personal PM monitor capable of direct PM10–2.5 size fraction collection was used. Participants living in the central region of North Carolina and enrolled in the NCAAES were asked to wear the monitor attached to a supporting backpack for 24-h collection periods. These volunteers were monitored for 2 to 4 days with subsequent gravimetric analysis of their PM samples. Personal PM10–2.5 mass concentrations were observed to be highly variable and ranged from 7.6 to 40.2 μg/m3 over an 8-month period. The median for this measurement from all participants (50th percentile) was 13.7 μg/m3. A coefficient of determination (r2) of 0.02 was established for community-based PM10–2.5 mass concentrations versus personal exposures. Similar coefficients established for PM2.5 mass revealed only a modest improvement in agreement (r2 = 0.12). Data from the exposure findings are reported here.