Objective Dust exposure is high in several industries. We investigated associations of exposure in paper mills, wood pellet plants, and iron foundries with lung function impairment. Methods Respirable silica, inhalable paper dust, or inhalable wood dust were collected as personal samples and spirometry was performed. Multiple linear regression analyzed associations with FEV₁%pred and FVC%pred. Results Wood pellet workers with high exposure to inhalable dust had lower FEV₁%pred (95% CI) (−9.4 [−16 to −2.6]) and FVC%pred (−9.8 [−15 to −4.0]) compared with lowest exposure level. Workers at paper mills and foundries had no dose-dependent association but lower FEV₁%pred and FVC%pred than in workers at wood pellets plants. Conclusions Increased exposure to inhalable wood dust is associated with decreased lung function. Foundry and paper mill workers have generally lower lung function than wood pellet workers. Spirometry should be considered in workers in industries with airborne particulate matter pollution.