Self-collected breath sampling for monitoring low-level benzene exposures among automobile mechanics

• Published in: The Annals of occupational hygiene Vol. 46; no. 5; pp. 489 - 500
• Main Authors: EGEGHY, Peter P, NYLANDER-FRENCH, Leena, GWIN, Kristin K, HERTZ-PICCIOTTO, Irva, RAPPAPORT, Stephen M
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.07.2002
• Subjects: Automobiles; Benzene - analysis; Biological and medical sciences; Breath Tests; Chemical and industrial products toxicology. Toxic occupational diseases; Environmental Monitoring; Female; Humans; Male; Medical sciences; Occupational Exposure; Smoking; Toxicology; Various organic compounds; Human; Expired air; Benzene; Self control; Occupational exposure; Repair; Commercial garage; Occupational medicine; Biological monitoring
• ISSN: 0003-4878; 1475-3162; 1475-3162
• DOI: 10.1093/annhyg/46.5.489

Automobile mechanics are exposed to benzene through their contact with gasoline vapor and engine exhaust. This study investigated the benzene uptake associated with these exposures. We first evaluated the reliability of self-collected breath samples among a subset of subjects and found good agreement between these samples and those collected under expert supervision (intraclass correlation coefficient 0.79, n = 69). We then used self-monitoring together with a longitudinal sampling design (with up to three measurements per worker) to measure benzene in air and benzene in end-exhaled breath among 81 workers from 12 automobile repair garages in North Carolina. A statistically significant difference (P < 0.0001, Mann-Whitney rank sum test) was observed between non-smokers and smokers for post-exposure benzene concentration in breath (median values of 18.9 and 39.1 micro g/m(3), respectively). Comparing pre- and post-exposure breath concentrations within these two groups, the difference was significant among non-smokers (P < 0.0001) but not significant among smokers (P > 0.05). Mixed effects regression analysis using backwards elimination yielded five significant predictors of benzene concentration in breath, namely benzene exposure (P < 0.0001), pre-exposure benzene concentration in breath (P = 0.021), smoking status (P < 0.0001), fuel system work (P = 0.0043) and carburetor cleaner use (P < 0.0001). The between-person variance component comprised only 28% of the total variance in benzene levels in breath, indicating that differences among individuals related to physiological and metabolic characteristics had little influence on benzene uptake among these workers.