The Menace of Air Pollution: An Update

Particulate MatterParticulate matter is a mixture of very fine solid particles and liquid droplets found in the air, such as sulfates, nitrates, ammonia, sodium chloride, black carbon, mineral dust, and water. 6It is classified according to its diameter: Coarse particles: 10-2.5 m. Fine particles: 2.5-0.1 m. Ultrafine particles: <0.1 m (100 nm).Particulate matter 2.5 and PM10 refer to particles that are <2.5 microns and 10 microns in diameter, respectively.A PM2.5 particle is 30 times thinner than a human hair and easily penetrates the respiratory system via inhalation, causing or worsening respiratory disease such as asthma, emphysema, and bronchitis, cardiovascular diseases, central nervous system (CNS) and reproductive dysfunction, and cancer.PM can originate from both indoor and outdoor sources.Indoor sources include soil or dust particles, smoke from cooking to cigarette smoking, while in public enclosed spaces such as metro trains and buses, PM may comprise metals such as iron, copper, manganese, and chromium, and even viruses.Outdoor sources include smoke from vehicles, coal power plants,