The Annals of Occupational Hygiene · 1982 · 15 citations · 0 references
Life SciencesMicrobiologyInfection PreventionMicrobial EcologyMycologyBacterial SporesMicrobial ContaminationOccupational Exposure PreventionRespiratory Disease PreventionRespiratory HygieneRespiratory ProtectionBacterial RetentionCartridge FiltrationFilter ValidationFungal Contamination PreventionMicrobial Contamination ControlPositive Pressure RespiratorsRespirator DecontaminationRespirator Performance Evaluation
Respirator filters marketed for protection against agricultural dusts have been tested for their ability to retain actinomycete spores implicated in farmer's lung disease. Because mixed cultures gave variable estimates, media selective for Thermoactinomyces spp., mostly T. vulgaris Tsiklinsky (spores 0.6–1.0 μm dia.) were used. Thermoactinomyces spores penetrated all filter types: up to 44% through nuisance dust filters, 3% through cartridge filters to British Standard BS2O91 Type A standard, 0.3% through BS 2091 Type B standard cartridges, 0.1–3.1% through different types of filter for a ventilated helmet and 0.5% through a powered positive-pressure respirator. The best disposable filtering face masks also allowed about 3% mean penetration but there was considerable sample to sample variation. Filters to BS 2091 Type B standard have been recommended for protection against farmer's lung but research on dose-response relationships is needed to determine whether 99.7% retention of spores is sufficient to prevent sensitization or disease.