Air Quality Related Values (AQRV) Summaries
View graphical summaries and reports of the status and trends of air-quality-related values (AQRVs) and other metrics in National Parks and other federal lands.
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Regional Haze
Vistas in national parks and wilderness areas are diminished by haze that causes discoloration, loss of texture, and diminished visual range. Visibility in Class I areas is Protected and regulated by the Regional Haze Rule.
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Ozone
Elevated ozone levels adversely affect human health and plants in sensitive ecosystems. Ozone concentrations are regulated by the primary and secondary National Ambient Air Quality Standards (NAAQS).
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Fine Particulate Matter (PM2.5)
Elevated amounts of PM2.5 adversely affect human health, visibility, and fine particulate deposition can contribute to ecosystem effects. PM2.5 levels are regulated by the National Ambient Air Quality Standards (NAAQS).
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Sulfur and Nitrogen Deposition
Deposition of sulfur and nitrogen compounds contributes to the acidification and eutrophication of sensitive terrestrial and aquatic ecosystems.
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Mercury
Mercury can bio-accumulate in fish, insects, and mammals. Human consumption of fish can cause adverse health effects.
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Featured Substance
Nitric acid | Name: | Nitric acid | | FormulaHTML: | HNO3 | | CASNum: | 7697-37-2 | | ACXNumber: | X1002177-5 | | Density: | 1.383 | | DOTNumber: | UN 2031 Oxidizer; UN 2032; NA 1760 Corrosive material; NA 1477 Oxidizer | | Comments: | Colorless, yellow, or red fuming liquid with an acrid, suffocating odor detectable at <5.0 ppm. Color fixative. OXIDIZING MATERIAL. | | MolecularWeight: | 63.0128 | | MeltingPoint: | -42 | | BoilingPoint: | 121 | | WaterSolubility: | miscible |
Featured Term
VOC Volatile organic carbons
Air Quality News
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