Particulate

Particulates, alternatively referred to as particulate matter (PM) or fine particles, are tiny particles of solid or liquid suspended in a gas. In contrast, aerosol refers to particles and the gas together. Sources of particulate matter can be man made or natural. Some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and various industrial processes also generate significant amounts of aerosols. Averaged over the globe, "anthropogenic" aerosols—those made by human activities—currently account for about 10 percent of the total amount of aerosols in our atmosphere. Increased levels of fine particles in the air are linked to health hazards such as heart disease, altered lung function and lung cancer.

cale classification

Among the most common categorizations imposed on particulates are those with respect to size, referred to as fractions. As particles are often non-spherical (for example, Asbestos fibers), there are many definitions of particle size.The most widely used definition is the "aerodynamic diameter". A particle with an aerodynamic diameter of 10 micrometers moves in a gas like a sphere of unit density (1 gram per cubic centimeter) with a diameter of 10 micrometers. PM diameters range from less than 10 nanometers to more than 100 micrometers. These dimensions represent the continuum from a few molecules up to the size where particles can no longer be carried by a gas.

The notation PM₁₀ is used to describe particles of 10 micrometers or less and PM_2.5 represents particles less than 2.5 micrometers in aerodynamic diameter. cite web
url = http://www.epa.gov/OCEPAterms/pterms.html
title = "Glossary: P"
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But because no sampler is perfect in the sense that no particle larger than its cutoff diameter passes the inlet, all reference methods allow a high margin of error.These are also sometimes referred to with other equivalent numeric values. Everything below 100 nm, down to the size of individual molecules is classified as ultrafine particles (UFP or UP)cite web
url = http://enhs.umn.edu/5103/particles/character.html
title = "A Review of the Measurement, Emission, Particle Characteristics and Potential Human Health Impacts of Ultrafine Particles: Characterization of Ultrafine Particles"
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coauthors = Thomas P. Brunshidle, Brian Konowalchuk, Ismail Nabeel, James E. Sullivan
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work = PubH 5103; Exposure to Environmental Hazards; Fall Semester 2003 course material
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The most concentrated particulate matter pollution tends to be in densely populated metropolitan areas in developing countries. The primary cause is the burning of fossil fuels by transportation and industrial sources.

Aerosol science

The field of aerosol science and technology has grown in response to the need to understand and control natural and manmade aerosols.

References

Further reading

* [http://earthobservatory.nasa.gov/Library/Aerosols/ Article at earthobservatory.nasa.gov describing the possible influence of aerosols on the climate]
* [http://www.grida.no/climate/ipcc_tar/wg1/160.htm The Intergovernmental Panel on Climate Change (the principal international scientific body on climate change) chapter on atmospheric aerosols and their radiative effects]
* [http://insideepa.com/secure/insider_display.asp?f=epa_2001.ask&docid=142006_links] InsideEPA.com, Study Links Air Toxics To Heart Disease In Mice Amid EPA Controversy
* Preining, Othmar and E. James Davis (eds.), "History of Aerosol Science," Österreichische Akademie der Wissenschaften, ISBN 3700129157 (pbk.)
* G Invernizzi et al., "Particulate matter from tobacco versus diesel car exhaust: an educational perspective". [http://tc.bmjjournals.com/cgi/reprint/13/3/219?ijkey=330b5aea15a8e36fcc2f4208cf99da58d84150f3 Tobacco Control 13, S.219-221] (2004)
* Sheldon K.Friedlander, "Smoke, Dust and Haze".
*JEFF CHARLTON "Pandemic planning: a review of respirator and mask protection levels."
* Hinds, William C., "Aerosol Technology: Properties, Behavior, and Measurement of Airborne Particles", Wiley-Interscience, ISBN 0471194107

See also

* Adequately wet
* Aerosol science
* Air pollution
* Biological warfare
* Clouds
* Criteria air contaminants
* Deposition
* Diesel particulate matter
* Dust
* Fog
* Global dimming
* Global warming
* Global Atmosphere Watch
* Haze
* Medical geology
* National Ambient Air Quality Standards (USA)
* Particulate mask
* "Pea soup" fog
* Pollution
* Radiological weapon
* Respirator
* Scrubber

External links

* [http://www.npi.gov.au/database/substance-info/profiles/69.html National Pollutant Inventory - Particulate matter fact sheet]
*WHO-Europe reports: [http://www.who.dk/document/e79097.pdf Health Aspects of Air Pollution (2003)] (PDF) and " [http://www.euro.who.int/document/E82790.pdf Answer to follow-up questions from CAFE (2004)] (PDF)
* [http://www.aaar.org American Association for Aerosol Research]
* [http://www.greenfacts.org/air-pollution/particulate-matter-pm/index.htm Particulate Air Pollution]
* [http://www.aerosol-soc.org.uk/history.asp Aerosol Society] - The Development of Aerosol Science in the United Kingdom
* [http://www.abc.net.au/catalyst/stories/s1630007.htm Watch and read 'Dirty Little Secrets'] , 2006 Australian science documentary on health effects of fine particle pollution from vehicle exhausts
* [http://www.tandf.co.uk/journals/titles/02786826.asp Aerosol Science and Technology]
* [http://www.hc-sc.gc.ca/ewh-semt/air/out-ext/reg_e.html#2 Canada-Wide Standards]
* [http://siteresources.worldbank.org/INTDATASTA/64199955-1178226923002/21322619/LGDB2007.pdf Little Green Data Book 2007] , World Bank. Lists C02 and PM statistics by country.
* [http://econ.worldbank.org/WBSITE/EXTERNAL/EXTDEC/EXTRESEARCH/0,,contentMDK:20785646~pagePK:64214825~piPK:64214943~theSitePK:469382,00.html Air Pollution in World Cities (PM10 Concentrations)]
* [http://themes.eea.europa.eu/Specific_media/air/indicators/particulates European Environment Agency]