Global systems are of concern because massive pollution in one part of the world can influence this area. In the area, the visual quality or visibility is affected by several of these. Locally, the system is sensitive to contributions to the air quality as well as how the air characteristics influence other factors of the environment of the area. The primary law influencing the air is the Clean Air Act of 1977 with amendments and the law of 1990. In addition to effects to human, air pollution can have a major influence on soil and nutrient availability to plants, on litter decomposition, and to lichen and other plants.
Health influences the quality of plants as forage for animals.
Air quality standards have ben established that specify maximum allowable levels for each major air pollutant. Even after massive amounts of research and great success, major questions about air pollutants remain. Research is needed to help protect human health and the environment from air pollution by providing the scientific and technical information needed to evaluate options for improving air quality in timely and cost-effective ways. Many air quality issues face legislative mandated assessments, regulatory actions, or other important policy decision within coming years. The environmental issues pose potentially large, but often unquantified, risks to human health and well-being.