Fresh water is a finite resource. The amount of fresh water supply provided by the hydrological cycle does not increase. Water everywhere on the planet is an integral part of the global hydrologic cycle. Precipitation originates as evaporation from land and the oceans.
EPA is currently reviewing the adequacy of the ozone and PM 10 standards. Largely in response to a court decision in favor of environmentalists Sierra Club v. Ruckelshaus, the amendments included a program for the prevention of significant deterioration PSD of air that was already clean.
This program would prevent polluting the air up to the national levels in areas where the air was cleaner than the standards. In Class I areas, areas with near pristine air quality, no new significant air pollution would be allowed.
Class I areas are airsheds over larger national parks and wilderness areas. In Class II areas a moderate degree of air quality deterioration would be allowed.
And finally, in Class III areas, air deterioration up to the national secondary standards would be allowed. Related to the prevention of significant deterioration is a provision to protect and enhance visibility in national parks and wilderness areas even if the air pollution is not a threat to human health.
The impetus of this section of the bill was the growing visibility problem in parks, especially in the Southwest. Throughout the s efforts to further amend the Clean Air Act were stymied.
President Ronald Reagan was opposed to any strengthening of the Act, which he argued would hurt the economy. In Congress, the controversy over acid rain between members from the Midwest and the Northeast further contributed to the stalemate. Over the next two years, the issues were hammered out between environmentalists and industry and between different regions of the country.
Major amendments to the Clean Air Act were finally passed in the fall of These amendments addressed four major topics: Most of this reduction came from old utility power plants. The law also creates marketable pollution allowances, so that a utility that reduces emissions more than required can sell those pollution rights to another source.
Economists argue that such an approach should become more widespread for all pollution control, to Courtesy of U.
Due to the failure of the toxic air pollutant provisions of the Clean Air Act, new, more stringent provisions were adopted requiring regulations for all major sources of varieties of toxic air pollution within 10 years. Areas of the country still in nonattainment for criteria pollutants will be given from three to 20 years to meet these standards.
These areas are also required to impose tighter controls to meet these standards. To help these areas and other parts of the country, the act requires stiffer motor vehicle emissions standards and cleaner gasoline. Finally, three chemical families that contribute to the destruction of the stratospheric ozone layer chlorofluorocarbons [CFCs], hydrochlorofluorocarbons [HCFCs], and methyl chloroform are to be phased out of production and use.
The Clean Air Act has met with mixed success. The national average pollutant levels for the criteria pollutants have decreased.
Nevertheless, many localities have not achieved these standards and are in perpetual nonattainment. Not surprisingly, major urban areas are those most frequently in nonattainment. The pollutant for which standards are most often exceeded is ozone, or smog.The National Wildlife Federation brings nature to life in the pages of our publications, inspiring people of all ages and reading levels to develop a deeper relationship with our natural world.
The Berlin Wall—symbol of a divided city within a divided nation within a divided continent—was grounded in decades-old historical divisions at the end of World War II. National Water Summary on Wetland Resources United States Geological Survey Water Supply Paper Wetland Management and Research Wetland Protection Legislation By Todd H.
Votteler, University of Texas This is done to compensate for the authorized destruction of the existing wetland. Air pollution is a general term that covers a broad range of contaminants in the atmosphere. Pollution can occur from natural causes or from human activities.
Number of species: Click on thumbnail photo for a larger version of image. Click on the scientific name for additional photos and information.
In reality, there is no natural boundary between the classes that humans define on these gradients (wetland/upland), and this issue is highlighted by the U.S. Fish and Wildlife Service's definition from Classification of Wetlands and Deepwater Habitats of the United States, which defines wetlands as "lands transitional between terrestrial and.