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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 2010 to 2022. 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.
The CCME standard for particulate matter 2.5 (PM 2.5) as of 2015 is 28 μg/m 3 (calculated using the 3-year average of the annual 98th percentile of the daily 24-hr average concentrations) and 10 μg/m 3 (3-year average of annual mean). PM 2.5 standards will increase in stringency in 2020. [273]
The following list of countries by air pollution sorts the countries of the world according to their average measured concentration of particulate matter in micrograms per cubic meter (μg/m 3). The World Health Organization's recommended limit is 10 micrograms per cubic meter, although there are also various national guideline values, which ...
The guidelines stipulate that PM 2.5 should not exceed 5 μg/m 3 annual mean, or 15 μg/m 3 24-hour mean; and that PM 10 should not exceed 15 μg/m 3 annual mean, or 45 μg/m 3 24-hour mean. [2] For ozone (O 3 ), the guidelines suggest values no higher than 100 μg/m 3 for an 8-hour mean and 60 μg/m 3 peak season mean. [ 2 ]
The highest AQI in India was recorded in New Delhi on 18th November 2024 with it being 1,081 and the concentration of PM2.5 - particulate matter measuring 2.5 microns or less in diameter that can be carried into lungs, causing deadly diseases and cardiac issues.
As an example, a measured NO x concentration of 45 ppmv in a dry gas having 5 volume % O 2 is: 45 × ( 20.9 - 3 ) ÷ ( 20.9 - 5 ) = 50.7 ppmv of NO x. when corrected to a dry gas having a specified reference O 2 content of 3 volume %. Note: The measured gas concentration C m must first be corrected to a dry basis before using the above equation.
0.5 ppm (1,300 μg/m 3) 3-hour Not to be exceeded more than once per year 40 CFR 50.5: Particulate matter (PM 10) Primary and Secondary 150 μg/m 3: 24-hour Not to be exceeded more than once per year on average over 3 years 40 CFR 50.6: Fine particulate matter (PM 2.5) Primary 9.0 μg/m 3 (12 μg/m 3 prior to May 6, 2024) [25] annual
Average global distribution of particulate matter (PM2.5) concentrations (2001-2006) Atmospheric particulate matter, also known as particulate matter, or PM, describes solids and/or liquid particles suspended in a gas, most commonly the Earth's atmosphere. [1]