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  2. Air quality index - Wikipedia

    en.wikipedia.org/wiki/Air_quality_index

    It is a health protection tool used to make decisions to reduce short-term exposure to air pollution by adjusting activity levels during increased levels of air pollution. The Air Quality Health Index also provides advice on how to improve air quality by proposing a behavioral change to reduce the environmental footprint.

  3. Air pollution in the United States - Wikipedia

    en.wikipedia.org/wiki/Air_pollution_in_the...

    Looking down from the Hollywood Hills, with Griffith Observatory on the hill in the foreground, air pollution is visible in downtown Los Angeles on a late afternoon.. Air pollution is the introduction of chemicals, particulate matter, or biological materials into the atmosphere that cause harm or discomfort to humans or other living organisms, or damage ecosystems.

  4. Pollution in the United States - Wikipedia

    en.wikipedia.org/wiki/Pollution_in_the_United_States

    Air pollution is caused predominantly by burning fossil fuels, cars, and much more. [4] Natural sources of air pollution include forest fires, volcanic eruptions, wind erosion, pollen dispersal, evaporation of organic compounds, and natural radioactivity. These natural sources of pollution often soon disperse and thin settling near their locale.

  5. NowCast (air quality index) - Wikipedia

    en.wikipedia.org/wiki/NowCast_(air_quality_index)

    PM 2.5 AQI of US monitors, calculated utilizing NowCast, courtesy US EPA PM2.5 AQI map, calculated utilizing NowCast, courtesy US EPA. The PM (particulate matter) NowCast is a weighted average of hourly air monitoring data used by the United States Environmental Protection Agency (USEPA) for real-time reporting of the Air Quality Index (AQI) for PM (PM 10 - particles less than 10 micrometers ...

  6. List of least-polluted cities by particulate matter concentration

    en.wikipedia.org/wiki/List_of_least-polluted...

    For instance, some places like Africa and South America lack air pollution reporting tools, so their pollution levels are probably not reflected in this list. Moreover, many cities from a certain country are featured in the list may only mean that they have large and wide air pollution monitoring networks, which may or may not be an indicator ...

  7. National Ambient Air Quality Standards - Wikipedia

    en.wikipedia.org/wiki/National_Ambient_Air...

    US counties that are designated "nonattainment" for the Clean Air Act's NAAQS, as of September 30, 2017. The U.S. National Ambient Air Quality Standards (NAAQS, pronounced / ˈ n æ k s / naks) are limits on atmospheric concentration of six pollutants that cause smog, acid rain, and other health hazards. [1]

  8. Environmental issues in the United States - Wikipedia

    en.wikipedia.org/wiki/Environmental_issues_in...

    Pollution from the Exxon Valdez oil spill. As with many countries, pollution in the United States is a concern for environmental organizations, government agencies, and individuals. Billions of pounds of toxic chemicals are released into the air, land, and waterways in the U.S. each year.

  9. Air pollution measurement - Wikipedia

    en.wikipedia.org/wiki/Air_pollution_measurement

    Air pollution measurement is the process of collecting and measuring the components of air pollution, notably gases and particulates. The earliest devices used to measure pollution include rain gauges (in studies of acid rain ), Ringelmann charts for measuring smoke , and simple soot and dust collectors known as deposit gauges . [ 1 ]