Pressure and temperature in and out of the dust respirator, skin temperature, humidity in the respirator, blood oxygen levels, and pulse rate of the workers using a conventional dust respirator or powered air-purifying respirator (PAPR) were measured during dust work to evaluate the effects of an electric fan on a worker’s physical load. The results showed that the pulse rate was significantly decreased and internal pressure of the respirator was significantly increased when using PAPR. From these results, it was considered that the pulse rate and the worker’s physical load might be reduced by increased internal pressure of the respirator. In addition, it was found that this effect appeared only in relatively light work in which the pulse rate is around 80 bpm.
