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Respirator performance rating tables have been constructed for hot, humid (29 degrees C, 95% RH); hot, dry (49 degrees C, 30% RH); and cold, dry (-32 degrees C, 70% RH) conditions. These tables convey expected wearer performance percentages compared to unmasked workers for various mask elements and work rates. The hot, humid condition was found to be the most severe overall. Many table entries approach 100%, thus leading to difficulties in correcting mask deficiencies.
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Johnson et al. (1992) studied this question.
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