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Worldwide, PM 10 concentrations of 70 μg/m 3 and PM 2.5 concentrations of 35 μg/m 3 have been shown to increase long-term mortality by 15%. [29] More so, approximately 4.2 million of all premature deaths observed in 2016 occurred due to airborne particulate pollution, 91% of which occurred in countries with low to middle socioeconomic status.
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 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]
Particulates or atmospheric particulate matter (see below for other names) are microscopic particles of solid or liquid matter suspended in the air.The term aerosol refers to the particulate/air mixture, as opposed to the particulate matter alone, [1] though it is sometimes defined as a subset of aerosol terminology. [2]
For example, the yearly averages of NO 2, PM 10 and PM 2.5 are divided by 40 μg/m 3, 40 μg/m 3 and 20 μg/m 3, respectively. The overall background or traffic YACAQI for a city is the arithmetic mean of a defined subset of these sub-indices. [22]
Below is a list of 526 cities sorted by their annual mean concentration of PM2.5 (μg/m 3) in 2022. [1] [2] By default the least polluted cities which have fewest particulates in the air come first.
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 ...
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