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  2. Air pollutant concentrations - Wikipedia

    en.wikipedia.org/wiki/Air_pollutant_concentrations

    Correcting concentrations for altitude. Air pollutant concentrations expressed as mass per unit volume of atmospheric air (e.g., mg/m 3, μg/m 3, etc.) at sea level will decrease with increasing altitude. The concentration decrease is directly proportional to the pressure decrease with increasing altitude.

  3. Air quality index - Wikipedia

    en.wikipedia.org/wiki/Air_quality_index

    An air quality index (AQI) is an indicator developed by government agencies [1] to communicate to the public how polluted the air currently is or how polluted it is forecast to become. [2][3] As air pollution levels rise, so does the AQI, along with the associated public health risk. Children, the elderly and individuals with respiratory or ...

  4. List of most-polluted cities by particulate matter concentration

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

    The January 2024 version of the WHO database contains results of ambient (outdoor) air pollution monitoring from almost 5,390 towns and cities in 63 countries. Air quality in the database is represented by the annual mean concentration of particulate matter (PM10 and PM2.5, i.e. particles smaller than 10 or 2.5 micrometers, respectively). [1 ...

  5. Air pollution - Wikipedia

    en.wikipedia.org/wiki/Air_pollution

    e. Air pollution is the contamination of air due to the presence of substances called pollutants in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. [1] It is also the contamination of the indoor or outdoor environment either by chemical, physical, or biological ...

  6. Air pollution measurement - Wikipedia

    en.wikipedia.org/wiki/Air_pollution_measurement

    Air quality monitoring sensors in Port Pirie, South Australia. 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 ...

  7. List of countries by air pollution - Wikipedia

    en.wikipedia.org/wiki/List_of_countries_by_air...

    Air pollution can affect nearly every organ and system of the body, negatively affecting nature and humans alike. Air pollution is a particularly big problem in emerging and developing countries, where global environmental standards often cannot be met. The data in this list refers only to outdoor air quality and not indoor air quality, which ...

  8. National Ambient Air Quality Standards - Wikipedia

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

    National Ambient Air Quality Standards. The U.S. National Ambient Air Quality Standards (NAAQS, pronounced / ˈnæks / naks) are limits on atmospheric concentration of six pollutants that cause smog, acid rain, and other health hazards. [1] Established by the United States Environmental Protection Agency (EPA) under authority of the Clean Air ...

  9. Air pollution in the United States - Wikipedia

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

    Regulation of air pollution is a shared responsibility between federal, state, and local governments. Since 1999, the EPA has used the air quality index (AQI) to communicate air pollution risk to the public, on a scale from 0 to 500, with six levels from Good to Hazardous. [10] (.