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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]
There is no safe level of particulates. Worldwide, exposure to PM 2.5 contributed to 4.1 million deaths from heart disease, stroke, lung cancer, chronic lung disease, and respiratory infections in 2016. [9] Overall, ambient particulate matter is one of the leading risk factor for premature death globally. [10]
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 2.5, also called fine particulate matter, consists of particles 2.5 μm and smaller. [29]
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 ...
This method raised the PM2.5 (particulate matter with a diameter smaller than 2.5 microns) per cubic meter to between 200 and 350. We then ran an air purifier at either maximum or auto setting.
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 5 micrograms per cubic meter, although there are also various national guideline values, which are ...
PM is most usually (but not always) expressed as mg/m 3 of air or other gas at a specified temperature and pressure. For gases, volume percent = mole percent 1 volume percent = 10,000 ppmv (i.e., parts per million by volume) with a million being defined as 10 6 .