Area sources are sources of pollution which emit a substance or radiation from a specified area.Examples of area sources include gas stations, dry-cleaners, print shops, autobody shops, furniture manufactures, and home sources such as wood stoves, pesticides, and cleaners. Area sources contribute to 26 percent of all man-made air toxic emissions according to EPA estimates.
For example, area sources ofair pollution are air pollutant emission sources which operate within a certain locale. TheU.S. Environmental Protection Agency has categorized 70 different categories of air pollution area source.[1]Locomotives operating on certain linear tracks are examples of aline source, whereas locomotives operating within a railyard are an example of an area source of pollution. Other area sources of air pollution are:
Water pollution manifestations of an area source—often callednonpoint source pollution—include:
In the 1950s or earlierhydrology transport models appeared to calculatesurface runoff, primarily for flood forecasting. Beginning in the early 1970s computer models were developed to analyze the transport of runoff carryingwater pollutants, which considereddissolution rates of various chemicals,infiltration into soils and ultimatepollutant load delivered toreceiving waters. One of the earliest models addressing chemical dissolution in runoff and resulting transport was developed in the early 1970s by theUnited States Environmental Protection Agency.[3][full citation needed] Thiscomputer model formed the basis of much of the regulatory framework that led to strategies for water pollution control vialand use and chemical handling techniques. People produce so much trash that half of it goes in water sources.[citation needed]