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Particulate pollution is pollution of an environment that consists of particles suspended in some medium. There are three primary forms: atmospheric particulate matter, [1] marine debris, [2] and space debris. [3] Some particles are released directly from a specific source, while others form in chemical reactions in the atmosphere.
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]
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 ...
Particulate matter (PM), also known as particulates, atmospheric particulate matter (APM), or fine particles, are microscopic solid or liquid particles suspended in a gas. [76] Aerosol is a mixture of particles and gas. Volcanoes, dust storms, forest and grassland fires, living plants, and sea spray are all sources of particles. Aerosols are ...
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.
Looking down from the Hollywood Hills, with Griffith Observatory on the hill in the foreground, air pollution is visible in downtown Los Angeles on a late afternoon.. Air pollution is the introduction of chemicals, particulate matter, or biological materials into the atmosphere that cause harm or discomfort to humans or other living organisms, or damage ecosystems.
The road itself wears and releases particulate matter into the air. [2] The friction between the tire surface and the road surface, which leads to tire abrasion, is also liable to abrade the road surface, especially where this is already fragmenting. Hence, road surface wear particles are also released into the atmosphere. [12]
Fossil fuel and biomass soot have significantly greater amounts of black carbon than climate-cooling aerosols and particulate matter, making reductions of these sources particularly powerful mitigation strategies. For example, emissions from the diesel engines and marine vessels contain higher levels of black carbon compared to other sources. [45]