常用N95型自吸过滤式防尘口罩阻力与过滤效率及影响因素

The aspiratory resistance and filtration penetration of N95 filtering-facepiece respirators used widely in China

目的 研究N95型自吸过滤式防尘口罩过滤效率和吸气阻力的影响因素,为降低阻力和提高口罩过滤效率提供改进依据.方法 购买目前市场销量领先且已获得认证的6个品牌,共21个型号的N95防尘口罩,在10～100L/min流量下测量口罩的过滤效率及吸气阻力,以过滤效率大于95％,吸气阻力小于350 Pa为合格标准,分析不同因素对口罩性能的影响.结果 全部21个型号的口罩中有2个型号的过滤效率低于95％,合格率为90.47％,过滤效率随流量增大而下降,呈线性负相关（r2=0.711,P＜0.05）.所有口罩的吸气阻力均符合国家标准的要求.吸气阻力随流量提高而增大,二者呈线性正相关（r2=0.878,P＜0.05）.不同品牌口罩的吸气阻力、过滤效率的差异有统计学意义（P＜0.05）;同一品牌不同型号口罩的过滤效率的差异无统计学意义（P＞0.05）,但吸气阻力的差异有统计学意义（P＜0.05）;未见通气阀对阻力和过滤效率的影响.结论 本研究测试的N95型防尘口罩吸气阻力均达到国家标准要求,过滤效率达标率超过90％.影响口罩吸气阻力的因素有口罩材质、尺寸和通气流量,影响口罩过滤效率的因素是口罩材质和通气流量.

Objective The objective of this study was to investigate the aspiratory resistance,filtration penetration and their influence factors of N95 filtering-facepiece respirators used widely in China.Methods The total of 6 brands and 21 models of N95 filtering-facepiece respirators which are certified and big sales on the market.The aspiratory resistance and filtration efficiency filter penetration were measured while air pump ran from 10 L/min to 100 L/min using differential pressure gauge and the PortaCount,respectively.Results The filtration penetrations for 2 of the 21 models were lower than 95%,and the qualified rate for all models was 90.47%.The filtration penetrations gradually decreased when ventilation flow of air pump increased.The negative correlation was observed between filtration penetration and ventilation flow （r2=0.711,P〈0.05）.The resistances of all 21 models of N95 respirators met the requirements of the national standard.The aspiratory resistance started to elevate with the increasing of ventilation flow,and a positive correlation between both （r2=0.878,P〈0.05）.Significant differences of filtration penetration and aspiratory resistance were observed among between different brands （P〈0.05） although no differences of filtration penetration existed among different models of one brand （P〉0.05）.But the differences of the aspiratory resistance among different models of one brand were statistically significant （P〈0.05）.Conclusion The aspiratory resistances of all N95 filteringfacepiece respirators used in this study met the requirements of the national standard.And the qualified ratio of filtration penetration of all models was higher than 90%.The influencing factors of aspiratory resistance included materials,size and ventilation flow.And influencing factors for filtration penetration were materials and ventilation flow.