A filter designated as P2 is a type of particulate filter for a respirator or half-mask, which falls into the second of three protection classes according to the European standard EN 143. This designation guarantees that the filter captures at least 94% of solid and liquid particles, so-called aerosols, dispersed in the air. It provides protection against moderately toxic and health-hazardous dusts, fumes, and aerosols, both water-based and oil-based. In practice, it is used, for example, when grinding wood, metal, or concrete, or when working with certain chemical substances in the form of fine powder or spray. Compared to the lower P1 class, which only protects against non-toxic particles, P2 offers a higher level of filtration. The highest protection is then provided by class P3, designed for highly toxic and carcinogenic substances.