Exposure to Inhalable Flour Dust and Respiratory Symptom of Workers in a Flour Mill in Iran

In 1999 the American conference of governmental industrial hygienists (ACGIH) proposed a threshold limit value (TLV) of 0.5 mg/m3 for flour dust with a sensitization notation. As part of this study, a relationship between flour dust concentrations and respiratory symptoms were examined. All 24 male flour subjects and 10 male controls were studied using air samples, ventilatory function testing, and questionnaire on respiratory symptoms. On average, breathing zone respirable and total flour dust in the flour mill were 4.97 mg/m3 and 12.11 mg/m3, respectively. The prevalence of cough, phlgm, difficulty to breathe, and respiratory symptoms were higher in subject group, also during an 8-h shift ventilatory function tests, it was demonstrated that respiratory capacities (FVC, FEV1, PEF) in the flour workers decreased, however, there was no significant statistical difference between case and control groups. Our results suggest that all of different job activities in flour mill may have a great impact on the development of work- related symptoms. Therefore, to minimize the risk of sensitization of occupational exposure during the work process, along with a decrease in mean 8-h TLV average exposure should be achieved.