Particulate matter inside of the alveolar macrophage

Particulate matter is a mixture of solid particles and liquid droplets found in the atmosphere. These present a feature as inhalable particles whose diameters are ≤10 m, the fine particles with diameters ≤2.5 m and ultrafine ≤0.1 m. Also, they can be made up of metals, nonmetals, metalloids, internal transitional elements, sulfates and nitrates, organic and elemental carbon and biological elements.  Macrophage is the primary defense of the innate immune system in the lung since it engulfs the toxic or allergic particles. Morphologically, particulate matter inside of macrophage is observed as numerous round dark granules of various size. In a guinea pig, the inhalation of fine particles in real time showed single round dark granules inside of macrophage. Also, they increased in bronchoalveolar lavage. Ultrafine particles can inhibit the phagocytosis. Nevertheless, macrophages contribute to the inflammatory response and clear the pulmonary alveolus.