AIRBORNE EXPOSURES TO PAH AND PM2.5 PARTICLES FOR ROAD PAVING WORKERSAPPLYING CONVENTIONAL ASPHALT AND CRUMB RUBBER-MODIFIED ASPHALT

Personal exposure monitoring was conducted for road paving workers in three states. A research objective was to characterize and compare occ upational exposures to fine respirable particles (< 2.5 mu m) and part icle-bound polycyclic aromatic hydrocarbons (PAHs) for road paving wor kers applying conventional (petroleum derived) asphalt and asphalt con taining crumb rubber from shredded tires. Workers not exposed to aspha lt fume were also included for comparison(to support the biomarker com ponent of this study). The rubber content of the crumb rubber modified (CRM) asphalt at the three study sites wets 12, 15, and 20%. A compar ison of some specific job categories from two sites indicates greater potential carcinogenic PAH exposures during CRM asphalt work, however, the site with the greatest overall exposures did not indicate any dif ferences for specific jobs. A statistical analysis of means for fine p article, pyrene and total carcinogenic PAH personal exposure shows, wi th two exceptions, there were no differences in exposures for these th ree measurement variables. One site shows significantly elevated pyren e exposure for CRM asphalt workers and another site similarly shows gr eater carcinogenic PAH exposure for CRM asphalt workers. Conventional and CRM asphalt worker airborne exposures to the PAH carcinogen marker , BaP, were very low with concentrations comparable to ambient air in many cities. However, this study demonstrates that asphalt road paving workers are exposed to elevated airborne concentrations of a group of unknown compounds that likely consist of the carcinogenic PAHs benz(a )anthracene, chrysene and methylated derivatives of both.