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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.
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]
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 .
Two alternative size-selective criteria, often used in atmospheric monitoring, are PM 10 and PM 2.5. PM 10 is defined by ISO as particles which pass through a size-selective inlet with a 50% efficiency cut-off at 10 μm aerodynamic diameter and PM 2.5 as particles which pass through a size-selective inlet with a 50% efficiency cut-off at 2.5 ...
CiteairII stated that having an air quality index that would be easy to present to the general public was a major motivation, leaving aside the more complex question of a health-based index, which would require, for example, effects of combined levels of different pollutants. The main aim of the CAQI was to have an index that would encourage ...
PM can be different sizes, such as PM 2.5 which are tiny particles of 2.5 microns in width or smaller, compared with PM 10 which are classified as 10 microns in diameter or less. A study in California found that increased exposure to PM 2.5 led to decreased sperm motility and increased abnormal morphology.
Various definitions of pollution exist, which may or may not recognize certain types, such as noise pollution or greenhouse gases.The United States Environmental Protection Administration defines pollution as "Any substances in water, soil, or air that degrade the natural quality of the environment, offend the senses of sight, taste, or smell, or cause a health hazard.
In 2013, the PM 2.5 level was 153 μg/m 3. These levels are considered very unhealthy. In Gwalior, the city with the worst air quality in India, the PM 10 and PM 2.5 levels were 329 μg/m 3 and 144 μg/m 3 respectively. For comparison, the PM 10 and PM 2.5 levels in London were 22 μg/m 3 and 16 μg/m 3 respectively. The PM levels in Delhi have ...