Pollution: atmospheric inputs

Nonpoint Source Pollution

Pollution: Atmospheric Inputs

caption Pollutants that industrial facilities discharge become airborne pollutants that are washed out of the atmosphere and deposited in rain or snowfall. This type of nonpoint source pollution can result in acid rain that can slow forest growth and contaminate soil. (Source: NOAA)

Industrial facilities often discharge pollutants into the atmosphere, typically through some type of smokestack. These airborne pollutants (for example, hydrocarbons, metals) can travel long distances. The pollutants are then deposited on surfaces (dry deposition) or washed out of the atmosphere in rain or snowfall (wet deposition).

Although the pollutants may have originated from a point source of air pollution such as a factory, the long-range transport and multiple sources of the pollutant make it a nonpoint source of pollution. Scientists estimate that approximately two-thirds of the lead and mercury and over half of the other trace elements that enter the Great Lakes originate from atmospheric inputs[1].

Acid rain has also become a major concern in some areas of the United States. Acid rain is created when sulfur dioxide and nitrogen oxides are discharged from industrial plants that burn fossil fuels like coal, oil, and natural gas. These compounds react with water, oxygen, and other atmospheric compounds to form acid rain.

Acid rain causes a cascade of effects that harm or kill fish and other aquatic organisms. As acid rain flows over and through soils, it releases aluminum into lakes and streams. Increased levels of aluminum are very toxic to fish. In addition, increased levels of aluminum cause fish to become chronically stressed. While chronic stress may not kill individual fish, it leads to lower body weight and smaller size, making the fish less able to compete for food and habitat[2].

Acid rain also damages forests. For example, acid rain can damage the surfaces of leaves and needles, reduce a tree's ability to withstand cold, and inhibit plant germination and reproduction. Prolonged exposure can cause forest soils to lose valuable nutrients like calcium and magnesium. Lack of nutrients causes trees to grow more slowly or to stop growing altogether.


  1. ^Hill, M.S. 1997. Understanding Environmental Pollution. Cambridge, UK: Cambridge University Press. 316 pp.
  2. ^USEPA. 2003. Cuyahoga River Area of Concern.
  3. NOAA National Ocean Service Education—Nonpoint Source Pollution: Atmospheric Inputs

Further Reading



(2011). Pollution: atmospheric inputs. Retrieved from http://www.eoearth.org/view/article/51cbeea57896bb431f699591


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C Michael Hogan wrote: 09-01-2011 17:02:38

Milton Beychok's comment is right on target. NOAA has produced a strange amalgamation of topics here. The EoE needs fresh articles on air pollution point, line and area sources. I shall message you on how we might go about this. Thanks for your insights.

Milton Beychok wrote: 08-30-2011 18:37:42

I don't quite understand why a photo of a point source of air pollution emissions (a single smokestack) is used in an article about nonpoint pollution sources. Nonpoint sources of air pollutant emissions are most commonly defined as being either: * Line sources — A line source is one-dimensional source of air pollutant emissions (for example, the emissions from the vehicular traffic on a roadway). * Area source — An area source is a two-dimensional source of diffuse air pollutant emissions (for example, the emissions from a forest fire, a landfill or the evaporated vapors from a large spill of volatile liquid). * Volume source — A volume source is a three-dimensional source of diffuse air pollutant emissions. Essentially, it is an area source with a third (height) dimension (for example, the emissions from an automobile paint shop with multiple roof vents or multiple open windows. Milton Beychok