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  2. Air quality guideline - Wikipedia

    en.wikipedia.org/wiki/Air_quality_guideline

    The World Health Organization guidelines were most recently updated in 2021. [1] The guidelines offer guidance about these air pollutants: particulate matter (PM), ozone (O 3), nitrogen dioxide (NO 2), sulfur dioxide (SO 2) and carbon monoxide (CO). [2] The WHO first released the air quality guidelines in 1987, then updated them in 1997. [2]

  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. Particulates - Wikipedia

    en.wikipedia.org/wiki/Particulates

    Average levels of PM 2.5 were measured using aqicn.org's World Air Quality Index data, and a formula developed by AirNow was used to convert the PM 2.5 figure into micrograms per cubic meter of air (⁠ μg / m 3 ⁠) values. Among the 70 capital cities investigated, Baghdad, Iraq is the worst performing one, with PM 2.5 levels going up +31.6 ...

  5. Particulate pollution - Wikipedia

    en.wikipedia.org/wiki/Particulate_pollution

    Particulate pollution is observed around the globe in varying sizes and compositions and is the focus of many epidemiological studies. Particulate matter (PM) is generally classified into two main size categories: PM 10 and PM 2.5. PM 10, also known as coarse particulate matter, consists of particles 10 micrometers (μm) and smaller, while PM 2 ...

  6. National Ambient Air Quality Standards - Wikipedia

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

    PM 10, coarse particles: 2.5 micrometers (μm) to 10 μm in size (although current implementation includes all particles 10 μm or less in the standard) PM 2.5, fine particles: 2.5 μm in size or less. Particulate Matter (PM) was listed in the 1996 Criteria document issued by the EPA.

  7. List of countries by air pollution - Wikipedia

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

    Rank Country particulate matter in (μg/m 3) WHO-Guideline=5 Loss of life expectancy (years) 1 Bangladesh 76.90 −6.93 2 India 55.80 −4.98 3 Pakistan 47.13 −4.13 4

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

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

    This list contains the top 500 cities by PM2.5 annual mean concentration measurement as documented by the World Health Organization covering the period from 2008 to 2017. The 2018 version of the WHO database contains results of ambient (outdoor) air pollution monitoring from almost 2700 towns and cities in 91 countries.

  9. Pollutant Standards Index - Wikipedia

    en.wikipedia.org/wiki/Pollutant_Standards_Index

    The Pollutant Standards Index ( PSI) is a type of air quality index used in Singapore, which is a number used to indicate the level of pollutants in air. Initially PSI was based on five air pollutants, but since 1 April 2014 it has also included fine particulate matter (PM 2.5 ). In addition to the PSI derived by averaging data collected for ...