Particulate matter (PM) air pollution is a product of modern civilization and poses a serious health hazard to the mankind.
According to the WHO, ambient (outdoor) air pollution, in both cities and rural areas, caused about 4.2 million premature deaths worldwide in 2016; the cause of mortality was exposure to the fine particulate matter (PM2.5).
Particulate matter (PM) is the term that refers to a mixture of solid and liquid particles of organic and inorganic substances suspended in the air. PM10 refers to the particles having diameters of 10 micrometers (microns or µm) or lesser. PM10 is also known as coarse particulate matter (coarse PM). PM2.5 refers to the particles having diameters of 2.5 micrometers or lesser. PM2.5 is also known as fine particulate matter (fine PM). Particles having a diameter of less than 0.1 micrometer are known as ultrafine particles.