Urban particulate matter in air pollution penetrates into the barrier-disrupted skin and produces ROS-dependent cutaneous inflammatory response in vivo

Particulate matters (PMs) are mixtures of particles suspended in the air. Their sources include factories, power plants, refuse incinerators, automobile, construction activities, fires and natural windblown dust [1]. Major components of PM are metals, organic compounds, materials of biologic origin, ions, and particle carbon core [2]. It also contains gases that are adsorbed onto the particles. PMs can be classified according to particulate size as PM0.1 (ultrafine particles, ≤ 0.1 μm), PM2.5 (fine particles, ≤ 2.5 μm), and PM10 (≤ 10 μm).