Adust storm blankets houses inTexas, 1935Global oceanic distribution of dustdepositionMap of dust in 2017Three years of use without cleaning has caused thislaptopheat sink to become clogged withdust bunny, and it can no longer be used.Domestic dust on a finger
Dust in homes is composed of about 20–50% dead skincells.[2] The rest, and in offices and otherbuilt environments, is composed of small amounts of plantpollen, humanhairs, animalfur,textile fibers,paper fibers,minerals from outdoor soil, burntmeteorite particles, and many othermaterials which may be found in the local environment.[3]
Atmospheric
Presentation on imported dust in North American skiesLarge dust storm overLibya
Atmospheric or wind-bornefugitive dust, also known asaeolian dust, comes from dry regions where high-speed winds can remove mostly silt-sized material, abrading susceptible surfaces. This includes areas wheregrazing,ploughing,vehicle use, and otherhuman behaviors have further destabilized theland, though not all source areas have been largely affected byanthropogenic impacts.[4] Dust-producing surfaces cover one-third of the global land area. These are made up ofhyper-arid regions like theSahara, which covers 0.9 billion hectares, anddrylands, which occupy 5.2 billion hectares.[5]
Dust in the atmosphere is produced bysaltation andabrasive sandblasting of sand-sized grains, and it is transported through thetroposphere. This airborne dust is considered anaerosol, and once in the atmosphere, it can produce strong localradiative forcing. Saharan dust, in particular, can be transported and deposited as far as theCaribbean and theAmazon basin and may affect airtemperature, cause ocean cooling, and alter rainfall amounts.[4]
Middle East
Dust in the Middle East has been a historic phenomenon. Recently, because ofclimate change and the escalating process ofdesertification, the problem has worsened dramatically. As a multi-factor phenomenon, there is not yet a clear consensus on the sources or potential solutions to the problem.
Iran
The dust inIraq andIran are migratory systems that move from west to east or east to west in the spring and have the highest intensity, concentration, and extent until mid-summer. The causes of their occurrence are the lack of humidity, dry environment, low rainfall, and annual droughts. Due to the decrease of rainfall in areas such as Iraq and Syria, most of the dust in Iran also originates from the regions of Iraq, Syria, and Jordan.[6]
In addition to the foreign foci, there are areas inside the country that have either formed new dust foci in recent years or were from the past and their extent has increased. Among these areas, parts of southernTehran, south ofAlborz province – which in the past were plains, riverbeds, seasonal lakes, and seasonal reservoirs – andGavkhoni wetland ofIsfahan province can be mentioned because they have become dry and prone to dust. Among other areas that have become dust centers,Qom province, the Qom salt lake and its surroundings can be mentioned, as well as theUrmia lake, which due to strong winds and due to the dryness of the lake and the reduction of its size, some areas of its bed which were underwater in the past are subject to wind erosion.[6]
In Iran, the dust directly affects more than 5 million people and has become a serious government issue recently. In theKhuzestan province, it has led to the severe increase ofair pollution. The amount ofpollutants in the air has surpassed more than 50 times the normal level several times in a year. Recently, initiatives such as Project-Dust have been established to study dust in the Middle East directly.[citation needed]
The continuation of drought has causedwater scarcity or drying up of some wetlands and lakes such asHamon andUrmia Lake. This has turned them into centers of dust.[6]
Director General of the Office of Desert Affairs of Iran's Natural Resources and Watershed Organization stated that according to the data of the 2018 studies, 30 million hectares of land in the country are affected by wind erosion, and 14 million hectares of this area are considered to be the focal points of wind erosion, which causes serious damage to infrastructure.[7]
Dust kicked up by vehicles traveling onroads is a significant source of harmfulair pollution.[8] Road dust consists of deposits of vehicle and industrialexhaust gas, particles fromtire andbrake wear,dust from paved roads orpotholes, and dust fromconstruction sites. Road dust is a significant contributor to the generation and release ofparticulates into the atmosphere.[9] Control of road dust is a significant challenge inurban areas, and also in other locations with high levels of vehicular traffic upon unsealed roads, such as mines andlandfills.
"Engine exhaust emissions, especially from those operating on diesel fuel, can be a significant source of fine particle generation from construction sites." Construction anddemolition activities can also produce a large amount ofconstruction waste. The dust andparticulates can become fugitive and airborne withvehicle movements both on and outside the sites, especially when it is windy and dry.[10]
Road dust may be suppressed by mechanical methods likestreet sweeper, vehicles equipped withvacuum cleaners,[11]vegetable oil sprays,[12] or with water sprayers.Calcium chloride can be used. Improvements inautomotive engineering have reduced the amount ofPM10s produced by road traffic; the proportion representing re-suspension of existing particulates has increased as a result.
Coal dust is responsible for therespiratory disease known aspneumoconiosis, includingcoal worker's pneumoconiosis disease that occurs amongcoal miners. The danger of coal dust resulted inenvironmental law regulating workplace air quality in some jurisdictions. In addition, if enough coal dust is dispersed within the air in a given area, in very rare circumstances, it can cause adust explosion. These circumstances are typically within confined spaces.
Control
Atmospheric
Tarps and netting are often used to reduce the amount of dust released fromconstruction sites.
Most governmental Environmental Protection Agencies, including theUnited States Environmental Protection Agency (EPA) mandate that facilities that generate fugitive dust, minimize or mitigate the production of dust in their operation. The most frequent dust control violations occur at new residential housing developments in urban areas. United States federal law requires that construction sites obtainplanning permissions to conduct earth moving and clearing of areas, so that plans to control dust emissions while the work is being carried out are specified. Control measures include such simple practices as spraying construction anddemolition sites with water, and preventing the tracking of dust onto adjacent roads.
Increasingcumulative effects—each new application builds on previous progress.
US federal laws require dust control on sources such as vacant lots, unpavedparking lots, anddirt roads. Dust in such places may be suppressed by mechanical methods,[citation needed] including paving or laying downgravel, or stabilizing the surface with water, vegetable oils[12] or otherdust suppressants, or by using water misters to suppress dust that is already airborne.[citation needed]
Domestic
House dust under a microscopeDomestic dust on a ribbonA video on reducing dust exposure in the workplace
Dust control is the suppression of solid particles with diameters less than 500micrometers (i.e. half a millimeter). Dust poses a health risk to children,[13] older people, and those with respiratory diseases.
House dust can become airborne easily. Care is required when removing dust to avoid causing the dust to become airborne. Afeather duster tends to agitate the dust so it lands elsewhere[citation needed].
CertifiedHEPA (tested to MIL STD 282) can effectively trap 99.97% of dust at 0.3 micrometers. Not all HEPA filters can effectively stop dust; while vacuum cleaners with HEPA filters, water, or cyclones may filter more effectively than without, they may still exhaust millions of particles per cubic foot of air circulated.Central vacuum cleaners can be effective in removing dust, especially if they are exhausted directly to the outdoors.
Air filters differ greatly in theireffectiveness. Laser particle counters are an effective way to measure filter effectiveness; medical grade instruments can test for particles as small as 0.3 micrometers. In order to test for dust in the air, there are several options available. Pre-weighed filter and matched weight filters made frompolyvinyl chloride or mixedcellulose ester are suitable for respirable dust (less than 10 micrometers in diameter).[14]
Dust resistant surfaces
A dust resistant surface is a state of prevention against dust contamination or damage, by a design or treatment of materials and items inmanufacturing or through a repair process[citation needed]. A reducedtacticity of a synthetic layer or covering can protect surfaces and release small molecules that could have remained attached. A panel, container or enclosure withseams may feature types of strengthenedstructural rigidity orsealant to vulnerableedges andjoins.
Outer space
Cosmic dust is widely present inouter space, where gas and dust clouds are the primary precursors forplanetary systems. Thezodiacal light, as seen in a dark night sky, is produced bysunlight reflected from particles of dust in orbit around theSun. The tails ofcomets are produced by emissions of dust and ionized gas from the body of the comet. Dust also covers solid planetary bodies, and vastdust storms can occur onMars which cover almost the entire planet. Interstellar dust is found between thestars, and high concentrations producediffuse nebulae andreflection nebulae.
Dust samples returned from outer space have provided information about conditions of the earlysolar system. Severalspacecraft have sought to gather samples of dust and other materials. Among these craft wasStardust, which flew past81P/Wild in 2004, and returned a capsule of the comet's remains to Earth.[16] In 2010 the JapaneseHayabusa spacecraft returned samples of dust from the surface of anasteroid.[17]
Atmospheric gallery
Dry, windy weather sends clouds of dust across south-eastern Australia.
House dust mites are present indoors wherever humans live.[18] Positive tests for dust mite allergies are extremely common among people with asthma. Dust mites are microscopicarachnids whose primary food is dead human skin cells, but they do not live on living people.[19] They and their feces and otherallergens are major constituents of house dust, but because they are so heavy they are not suspended for long in the air. They are generally found on the floor and other surfaces until disturbed (by walking, for example).[18] It could take between twenty minutes and two hours for dust mites to settle back out of the air.
Dust mites are a nesting species that prefer a dark, warm, and humidclimate. They flourish inmattresses,bedding,upholstered furniture, andcarpets.[20] Their feces includeenzymes that are released upon contact with a moist surface, which can happen when a person inhales, and these enzymes can kill cells within thehuman body.[21] House dust mites did not become a problem until humans began to use textiles, such asblankets andclothing.[22]
^van Bronswijk, J. E. M. H. (1981).House Dust Biology for Allergists, Acarologists and Mycologists. J. Bronswijk. p. 37.ISBN978-90-275-3501-6.OCLC9757081.
^Jickells, T. D.; An, Z. S.; Andersen, K. K.; Baker, A. R.; Bergametti, G.; Brooks, N.; Cao, J. J.; Boyd, P. W.; Duce, R. A.; Hunter, K. A.; Kawahata, H.; Kubilay, N.; Laroche, J.; Liss, P. S.; Mahowald, N.; Prospero, J. M.; Ridgwell, A. J.; Tegen, I.; Torres, R. (April 1, 2005). "Global Iron Connections Between Desert Dust, Ocean Biogeochemistry, and Climate".Science.308 (5718):67–71.Bibcode:2005Sci...308...67J.CiteSeerX10.1.1.686.1063.doi:10.1126/science.1105959.PMID15802595.S2CID16985005.
^Peel, G.; Michielen, M.; Parker, G. (July 8–12, 2001). "Some aspects of road sweeping vehicle automation".2001 IEEE/ASME International Conference on Advanced Intelligent Mechatronics. Proceedings (Cat. No.01TH8556). 2001 IEEE/ASME International Conference on Advanced Intelligent Mechatronics. Vol. 1.Como:Institute of Electrical and Electronics Engineers. pp. 337–342.doi:10.1109/AIM.2001.936477.ISBN978-0-7803-6736-4.
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