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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.
Types of atmospheric particles include suspended particulate matter; thoracic and respirable particles; [4] inhalable coarse particles, designated PM 10, which are coarse particles with a diameter of 10 micrometers (μm) or less; fine particles, designated PM 2.5, with a diameter of 2.5 μm or less; [5] ultrafine particles, with a diameter of ...
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 tiniest of these — known as PM 2.5 because they are less than 2.5 microns in diameter — can get deep into human lungs and are mostly created by burning fuels. Coarser particles, known as PM 10, are linked to agriculture, roadways, mining or the wind blowing eroded dust, according to the WHO.
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.
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 ...
These units express the concentration of air pollution in terms of the mass or volume of the pollutant, and they are commonly used for measurements of both gaseous pollutants, such as nitrogen dioxide, and coarse (PM 10) and fine (PM 2.5) particulates.
[1] Annual arithmetic mean of a minimum of 104 measurements in a year at a particular site, such as taken twice weekly as uniform 24-hour samples. [2] 24/8/1 hourly monitored values, as applicable, shall be complied with 98% of the time, they may exceed the limits but not on two consecutive days of monitoring.