KN95 rated half-face particulate respirators are the standard issue in China. This mask have been tested and rated to match the N95 United States threshold for 95% filtration. Our masks are CE certified FPP2, manufactured to the EN 149:2001 standards with CE mark as required in Europe (and ruled acceptable by the FDA on March 24th, 2020 for domestic American healthcare providers, and formally adopted by the CDC). Mask provides the intended effectiveness of filtering 95 percent of particles with a mass median diameter of 0.3 micrometers. Therefore, these masks can protect you well from PM10, PM2 .5, and even smaller particles.Only 1 respirator is included.