Urban Outdoor Pollution (UOP): It refers to the air pollution experienced by people living in and around urban areas, generally in open space, for example, roads.

Indoor Air Pollution (IAP) refers to pollutants found indoors, generally due to inefficient fuel consumption, chemical pollution to building material, and so on. UOP contributes to IAP. Nearly two million lives are lost due to Indoor Air Pollution, the most common victims being women, and children under the age 5.