Five kinds of respirators were selected to analyze the protective performance of four kinds of atmospheric particulate matter in the real environment of Beijing with different pollution levels, and the effects of particle, respirator types, inspiratory flow rate and atmospheric PM_2.5 concentration on the protective performance of respirators were studied. The results showed that the four factors had significant effects on the protective performance of the facemasks. The particle protective performance of facemasks increased with the increase of particle size. The protective performance of four types of KN95 or KN90 facemasks for actual atmospheric particles could reach 80%, while the protective performance of disposable medical surgical facemasks was far lower than the above four types. The inspiratory flow also significantly affected the protective performance of the facemask, possibly due to the difference in filter material performance and leakage rate at different flow rates. The influence of atmospheric PM_2.5 concentration on the protective performance of different facemasks was complex 

and there was not a simple correlation.

选取5种口罩对北京市不同污染程度的真实环境中4种大气颗粒物的防护作用进行分析, 研究颗粒物粒径、口罩种类、吸气流速和环境大气PM_2.5浓度对口罩防护作用的影响。结果表明, 4种因素均对口罩防护作用具有显著影响。口罩的颗粒物防护作用呈现随颗粒物粒径增加而升高的趋势。4种KN95或KN90口罩对实际大气颗粒物的防护作用可以达到80%, 一次性医用外科口罩的防护作用远低于以上4种。气体流速也显著地影响口罩的防护作用, 可能是由于在不同流速下滤料性能和泄漏率的差异。环境大气_PM2.5浓度对不同口罩防护作用的影响较为复杂, 未呈现简单的相关性。