Estimation of personal exposure to asbestos of brake repair workers.

Exposure assessments are key tools to conduct epidemiological studies. Since 2010, 28 riveters from 18 brake repair shops with different characteristics and workloads were sampled for asbestos exposure in Bogotá, Colombia. Short-term personal samples collected during manipulation activities of brake products, and personal samples collected during non-manipulation activities were used to calculate 103 8-h TWA PCM-equivalent personal asbestos concentrations. The aims of this study are to identify exposure determinant variables associated with the 8-h TWA personal asbestos concentrations among brake mechanics, and propose different models to estimate potential asbestos exposure of brake mechanics in an 8-h work-shift. Longitudinal-based multivariate linear regression models were used to determine the association between personal asbestos concentrations in a work-shift with different variables related to work tasks and workload of the mechanics, and some characteristics of the shops. Monte Carlo simulations were used to estimate the 8-h TWA PCM-Eq personal asbestos concentration in work-shifts that had manipulations of brake products or cleaning activities of the manipulation area, using the results of the sampling campaigns. The simulations proposed could be applied for both current and retrospective studies to determine personal asbestos exposures of brake mechanics, without the need of sampling campaigns or historical data of air asbestos concentrations.