In order to make clear the filtration efficiency of respirators on particulate matter (PM) based on real respiratory environment, three kinds of face masks were selected to study the effects of mask type, wearing mode, inspiratory rate on PM filtration efficiency and risk reduction. Results show that the general trend for PM filtration efficiencies of masks was KN95 mask > surgical mask > activated carbon mask. The air leakage from the gaps between the face and the masks played an important role in achieving high protection performance, while the effect of inspiratory rate on the filtration efficiency of the mask was not obvious. The filtration efficiency of wearing masks under real-life conditions for different size particles showed a tendency to increase with the particle size. More than 93.5% reduction rate for the deposition flux of coarse and fine particles in the human respiratory system in the waste plastic crushing workshop was obtained by wearing KN95 mask. It is suggested that workers can select different types of masks according to the air conditions and the work tasks in the workshop.