Zoology · Ch 13 — Environmental Issues
Sources
Sources
Air pollution sources are grouped into four broad categories. Transport sources include cars, buses, airplanes, trucks, and trains -- mobile emitters that release pollutants as they move. Stationary sources are fixed-location emitters such as power plants, incinerators, oil refineries, and other industrial facilities and factories. Area sources are diffuse, spread-out sources rather than single points, such as agricultural wood or stubble burning and fireplaces. Natural sources include wind-blown dust, wildfires, volcanoes, and lightning -- pollution that occurs without any human activity. Understanding which category a given source of pollution falls into matters for control strategy: mobile and area sources generally need behavioural or regulatory intervention (like emission standards or burning …
What this figure shows. A schematic diagram titled 'Sources of air pollution' that sorts air-pollution sources into four labelled categories arranged around a central 'Pollutant emissions' node. The Natural category lists lightning, volcanoes and wildfires as sources that occur without human activity. The Area category lists fertilizer application and similar diffuse agricultural sources. The Stationary category lists industry, power plants and sewage treatment plants as fixed-location emitters, alongside cities as a general urban stationary-source grouping. The Mobile category lists airplanes, cars, trucks, buses, and three- and two-wheelers as sources that move while emitting, with a separate 'Oil & Gas' extraction-and-processing source noted alongside the mobile category. The figure functions as a single-glance sorting chart showing that air pollution arises from a genuinely wide spread …