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Annual seasonal average particulate matter concentrations have been recorded as high as 279 μg/m 3 (micrograms per cubic meter). [citation needed] The World Health Organization's recommended annual mean PM 10 level is 20 μg/m 3, [296] which means that Ulaanbaatar's PM 10 annual mean levels are 14 times higher than recommended. [citation needed]
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]
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 Annual mean, averaged over 3 years 40 CFR 50.18: Secondary 15 μg/m 3: annual Annual mean ...
The AQI level is based on the level of six atmospheric pollutants, namely sulfur dioxide (SO 2), nitrogen dioxide (NO 2), suspended particulates smaller than 10 μm in aerodynamic diameter (PM 10), [19] suspended particulates smaller than 2.5 μm in aerodynamic diameter (PM 2.5), [19] carbon monoxide (CO), and ozone (O 3) measured at the ...
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.
Particulate matter (PM) in the atmospheric air or in any other gas cannot be expressed in terms of ppmv, ppbv, volume percent or mole percent. PM is most usually (but not always) expressed as mg/m 3 of air or other gas at a specified temperature and pressure.
In United States environmental law, a non-attainment area is an area that exceeds pollution limits for one or more criteria pollutants: ozone (O 3), atmospheric particulate matter (PM 2.5 /PM 10), lead (Pb), carbon monoxide (CO), sulfur oxides (SO x), and nitrogen oxides (NO x). [1]
Types of atmospheric particles include suspended particulate matter; thoracic and respirable particles; inhalable coarse particles, designated PM10, which are coarse particles with a diameter of 10 micrometers (μm) or less; fine particles, designated PM2.5, with a diameter of 2.5 μm or less; ultrafine particles; and soot.