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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 ]
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]
The CCME standard for particulate matter 2.5 (PM 2.5) as of 2015 is 28 μg/m 3 (calculated using the 3-year average of the annual 98th percentile of the daily 24-hr average concentrations) and 10 μg/m 3 (3-year average of annual mean). PM 2.5 standards will increase in stringency in 2020. [273]
The World Health Organization's recommended limit is 10 micrograms per cubic meter, although there are also various national guideline values, which are often much higher. Air pollution is among the biggest health problems of modern industrial society and is responsible for more than 10 percent of all deaths worldwide (nearly 4.5 million ...
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.
Mothers who were exposed to PM2.5 weekly during gestation, were likely to have a child diagnosed with asthma by the age 6 years. Many of the mothers exposed to PM2.5 were ethnic minorities (54% Hispanic, 30% black), had 12 or fewer years of education (66%), and did not smoke in pregnancy (80%). [32]
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 Pollutant Standards Index (PSI) is a type of air quality index used in Singapore, which is a number used to indicate the level of pollutants in air.Initially PSI was based on five air pollutants, but since 1 April 2014 it has also included fine particulate matter (PM 2.5).