Grain dust is a health hazard for farmers working at their grain bins. Exposure to grain dust can give rise to many respiratory diseases. Farmers are recommended to wear facepiece respirators for protection. This research used a simulated environment and manikin system to evaluate the protection factors of four common respirators worn by farmers when working at their on-farm bins.
Measurements were conducted on four respirators: Nuisance dust mask, N95, N95 with valve, and P100. Each was tested on a manikin system in a simulation chamber. Four respirable dust concentrations (5, 10, 15, 20 mg/m3) and two inhalation flow rates (30 and 85 L/min) were tested for a 30-minute period. An artificial leak area was added at the nose. An OSHA standardized equation was used to calculate the Protection Factor (PF) and the Maximum Use Concentration (MUC) for each respirator type. These calculations were compared to observations made in the simulator.
Results show the P100 respirator provides the highest protection under both inhalation conditions. Both N95 respirators provided very close protection factors, with no significant difference. These three types provided better protection than the nuisance mask. No statistical difference was found between the respirator types when measuring dust concentrations at different levels (5, 10, 15, 20 mg/m3). Because the types of the respirators and the inhalation flow rates had significant effects on protection factors, the MUC was calculated for each respirator with two inhalation rates. All masks tested could provide a Protection Factor 10 which meets the OSHA required APF for half masks. However, the MUC of the nuisance mask was lower than the respirable dust concentration measured in grain bins and therefore should not be used in these environments.
Three respirators (N95, N95 with valve, and P100) provide adequate protection for grain bins. The respirators use time varied by the concentration of respirable dust in the simulated environment. While the P100 respirator is the best choice, N95 respirators are adequate if they are changed every 40 to 60 minutes. These recommendations will be incorporated into future education programs to improve Ohio farmers life quality