RELATIONSHIP OF RESPIRATORY HEALTH-STATUS TO GRAIN DUST IN A WITWATERSRAND GRAIN MILL - COMPARISON OF WORKERS EXPOSURE ASSESSMENTS WITH INDUSTRIAL-HYGIENE SURVEY FINDINGS

Objective measures of exposure furnished by dust monitoring are both c ostly and time consuming and require a sufficient level of technology. However, they are important in demonstrating exposure-response relati onships, in furnishing information necessary to establish environmenta l control levels, and to assess if interventions, for instance, improv ing dust control, have been effective. In this paper respiratory sympt oms and cross-shift changes in spirometric lung function were related to dust exposure level in a grain mill assessed in two ways, subjectiv ely (by workers themselves on a four point scale) and objectively (by personal dust monitoring). Health indicators that depend on the indivi dual's perception (e.g., symptoms) correlated more closely with the su bjectively assessed dust category, while health indicators that were m easured objectively (e.g., cross-week FVC and FEV1 change) correlated more closely with the objectively assessed dust category. However, the patterns of relationship of respiratory health indicators to either d ust category were similar, and exposure assessed by one method was, to a large extent, a proxy for the other. The most significant predictor of workers' choice of dust exposure category was the measured dust le vel. These findings indicate that exposure categories based on workers ' assessment of dustiness can be a useful tool in etiologic research, in particular in establishing exposure-response relationships. (C) 199 3 Wiley-Liss, Inc.