Grain Dust and Lung Function

Abstract

Grain dust exposure has been associated with both acute and chronic respiratory abnormalities. Wesought to answer two questions with regard to this exposure: (1) is there 8 doseresponse relationship between grain dust and respiratory abnormalities, and (2) is there evidence to suggest that the allowable exposure (currently 10 mg/m' in Canada) be iowered? We compared respiratory symptoms and lung function among 454 grain elevator workers and 55 civic workers to estimates of lifetime average grain dust exposure. A total of 781 personal air samples representing 20 different Job titles over a 15-yr period were used to construct a Jobtitie-time period matrix for average dust exposure levels. The matrix was applied to each worker's detailed Job history to obtain a velue for estimated cumulative and average dust exposure. Significant dose-response relationships were seen for chronic phiegm production, breathiessness on exertion, FEV and FVC; and dose-response trends were evident for the iongltudlnal change In both FEV, and FVC.Workers with estimated everage exposure between 4 and 9 mg/m' were found to have significantly lower values for FEV, and FVC compared to both grain workers exposed to <4 mglm' on average and civic workers, despite no difference in duration of employment among these groups. The results Indicate a strong dose-response relationship between grain dust exposure and both respiratory symptoms and lung function and also suggest that the current Canadian allowable exposure level of 10 mg/m' is too high. AM REV RESPIR DIS 1991; 144:1314-132