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Air Pollution Impacts

Everglades National Park

Natural and scenic resources in Everglades National Park (NP) are susceptible to the harmful effects of air pollution. Mercury, nitrogen, sulfur, ozone, and fine particles impact natural resources such as wildlife, surface waters, and vegetation, and scenic resources such as visibility. Click on the tabs below to learn more about air pollutants and their impacts on natural and scenic resources at Everglades NP.

  • Toxics & Mercury
  • Nitrogen & Sulfur
  • Ozone
  • Visibility
Photo of a Florida panther at Everglades NP, Florida.
Animals such as the Florida panther at Everglades NP in Florida are sampled to analyze mercury levels.

Airborne toxics, including heavy metals like mercury, can be deposited by rain or dry deposition (e.g., dust) into park ecosystems and accumulate in organisms. When mercury converts to methylmercury in the environment and enters the food chain, effects can include reduced reproductive success, impaired growth and development, and decreased survival. Other toxic air contaminants of concern include pesticides, industrial by-products, and more recently developed chemicals such as flame retardants for fabrics, some of which are also known or suspected to cause cancer or other serious health effects in humans and wildlife.

Effects of mercury and toxics at Everglades NP include:

  • Comparatively high mercury deposition at the park (NPS 2010 [pdf, 2.8 MB]), likely because of large nearby sources of mercury such as coal-burning power plants and waste incinerators;
  • Elevated mercury levels in sediment, vegetation, and in all levels of the food chain, from frogs, fish, wading birds, to fish-eating birds such as the great egret and the bald eagle, pythons, alligators, and the endangered Florida panther (Guentzel et al. 1998; Krabbenhoft 2010; Rumbold et al. 2002; Rumbold 2005; Sundlof et al. 1994; Ugarte et al. 2005);
  • Mercury levels in wading birds at concentrations typically associated with neurologic and reproductive impairment (Sundlof et al. 1994);
  • Mercury levels in frogs and pythons above human health thresholds (Krabbenhoft 2010; Ugarte et al. 2005), a concern for areas that permit harvesting and consumption;
  • Statewide mercury fish consumption advisory for freshwater, coastal, and other waterbodies (EPA 2008), and additional fish consumption advisories for contaminants such as dioxin, PCBs, and pesticides (Florida DOH 2009 [pdf, 918 KB]);
  • Elevated concentrations of pesticides, particularly endosulfan, in sediment, surface waters, and several native fish (Carriger et al. 2006; Carriger and Rand 2008a and b; Rand and Carriger 2004; Rand et al. In Prep).

Get Mercury Data »


River of Grass at Everglades NP, Florida, a wetland ecosystem sensitive to nutrient nitrogen.
Wetland plants adapted to low nitrogen environments at Everglades NP, Florida, are sensitive to the effects of atmospheric nitrogen deposition.

Nitrogen and sulfur compounds deposited from air pollution can harm surface waters, soils, and vegetation. Nitrogen acts as a fertilizer, contributing to overenrichment and eutrophication in the park, adding to problems caused by phosphorus runoff from agriculture. Wetland plant species adapted to low nitrogen environments are particularly sensitive to the effects of nutrient nitrogen enrichment as species relationships are altered, sometimes increasing the establishment of non-native species at the expense of the rare species. These nutrient inputs can also cause changes to soil nutrient cycling (Sullivan et al. 2011a; Sullivan et al. 2011b [pdf, 12 MB]). Concentrations of ammonium in wet deposition, an indication of nearby agricultural sources, contribute to nitrogen deposition and levels are increasing at the park (NPS 2010 [pdf, 2.8 MB]). Nitrogen, together with sulfur, can also acidify soils and waterbodies, but the freshwater and saltwater ecosystems at Everglades NP are well-buffered from these effects. Sulfur, however, has an essential role in the methylation of mercury, leading to toxic accumulation of mercury in fish and wildlife. Although the main source of sulfur is runoff from northern Everglades agriculture, local emissions from coal-burning power plants might contribute to this problem (more »).

Get Nitrogen & Sulfur Data »


Photo of a healthy Sambucus canadensis (American elder) at Everglades NP, Florida.
While ground-level ozone concentrations are generally low at Everglades NP, Florida, there are a few ozone-sensitive species present in the park, such as sambucus canadensis (American elder).

Naturally-occurring ozone in the upper atmosphere absorbs the sun’s harmful ultraviolet rays and helps to protect all life on earth. However, in the lower atmosphere, ozone is an air pollutant, forming when nitrogen oxides from vehicles, power plants, and other sources combine with volatile organic compounds from gasoline, solvents, and vegetation in the presence of sunlight. In addition to causing respiratory problems in people, ozone can injure plants. Ozone enters leaves through pores (stomata), where it can kill plant tissues, causing visible injury, or reduce photosynthesis, growth, and reproduction.

There are a few ozone-sensitive plants in Everglades NP including Sambucus canadensis (American elder) and Spartina alterniflora (smooth cordgrass). The low levels of ozone exposure at Everglades NP make the risk of foliar ozone injury to plants low (Kohut 2004 [pdf, 130 KB]).

Search the list of ozone-sensitive plant species (pdf, 184 KB) found at each national park.

Get Ozone Data »


Photograph of a bird's-eye-view of a scenic vista at Everglades NP, Florida.
Human-caused haze and fine particles of air pollution sometimes reduce visibility of scenic vistas like this one at Everglades NP, Florida.

Visitors come to Everglades NP to enjoy sights of the some of the most rare and endangered species in the U.S., including the manatee, American crocodile, and plant communities such as mangrove and cypress swamps. Unfortunately, park vistas are sometimes obscured by haze caused by fine particles in the air. Many of the same pollutants that ultimately fall out as nitrogen and sulfur deposition contribute to this haze and visibility impairment. Organic compounds, soot, and dust reduce visibility as well.

Visibility effects at Everglades NP include:

  • Reduced visibility due to human-caused haze and fine particles of air pollution;
  • Reduction of the average natural visual range from about 100 miles (without the effects of pollution) to about 40 miles because of pollution at the park;
  • Reduction of the visual range to below 20 miles on high pollution days.

(Source: IMPROVE 2010)

Explore scenic vistas through a live webcam at Everglades National Park.

Get Visibility Data » 


Featured Content

Studies and Monitoring icon

Studies and monitoring help the NPS understand the environmental impacts of air pollution. Access air quality data and see what is happening with Studies and Monitoring at Everglades NP.

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Last Updated: December 30, 2016