We fail to see how polluted the air that we breathe is. The reason behind this is that most of the air pollutants are not visible to the naked eye. One such pollutant is particulate matter (PM). Particulate air pollution is a mixture of solid, liquid or solid and liquid particles suspended in the air. Several components, like acids (sulphates and nitrates), organic chemicals, metals, and soil or dust particles, constitute particle matter. The particles vary in size, composition and origin, and are categorized into coarse, fine and ultrafine.