Simultaneous exposure to airborne flour particles and thermal load as cause of respiratory impairment

Summary In order to estimate whether only simultaneous exposure to both airborne flour particles and unfavorable thermal environment alone cause the development of nonspecific respiratory disease or whether sole exposure to flour aerosols is likely to cause impairment of the respiratory system, a group of 80 millers and 130 bakers, all nonsmokers, were examined. Both millers and bakers were exposed to approximately the same concentration of airborne flour particles but the latter worked under considerable thermal load. It was found that between millers and bakers the difference in the prevalence of respiratory symptoms was not statistically significant. Although the differences between the mean measured and the mean predicted ventilatory function parameters (FVC, FEV₁, PEF, MEF 50%, MEF 75%) were significant both in millers and bakers, they did not differ significantly between these two groups. This finding suggests that exposure to flour dust may cause the development of chronic nonspecific respiratory disease and a reduction of ventilatory lung capacity irrespective of simultaneous heat load.