Review on polymeric, inorganic, and composite materials for air filters: From processing to properties

Abstract

Particulate and gaseous air pollutants pose a threat to human health and contribute to climate change. By today, air filters, stationary and portable, are markedly improved and can often provide innocuous air pollution levels. After introducing the classification and standards on air filters, the influence of the processing route and its parameters on the resulting air filter properties and consequently its performance are discussed. Numerous tools are presented to adjust structural properties such as fiber or pore diameter, specific surface area, surface charge, hydrophilicity, or photocatalytic activity to achieve the desired performance in terms of high filtration efficiencies, sufficient mechanical stability, regeneration eligibility, antimicrobial and optical properties. In particular, inorganic and composite materials as well as nonfibrous structures are covered, which are currently holding an outsider position in an air filter community dominated by polymeric materials and fibrous structures.