Dust are fine particles of solid matter.[1] It generally consists of particles in the atmosphere that come from various sources such as soil, dust lifted by wind (an aeolian process), volcanic eruptions, and pollution. Dust in homes, offices, and other human environments contains small amounts of plant pollen, human and animal hairs, textile fibers, paper fibers, minerals from outdoor soil, human skin cells, burnt meteorite particles, and many other materials which may be found in the local environment.[2]

A dust storm blankets Texas houses, April 1935
Global oceanic distribution of dust deposition
Map of dust in 2017

Dust Mites

Laptop dust
Three years of use without cleaning has caused this laptop heat sink to become clogged with dust, and it can no longer be used as it may overheat.
Hausstaub auf einem Finger
Domestic dust on a finger

House dust mites are present indoors wherever humans live. Positive tests for dust mite allergies are extremely common among people with asthma. Dust mites are microscopic arachnids whose primary food is dead human skin cells, but they do not live on living people. They and their feces and other allergens which they produce 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). It could take somewhere between twenty minutes and two hours for dust mites to settle back down out of the air.

Dust mites are a nesting species that prefers a dark, warm, and humid climate. They flourish in mattresses, bedding, upholstered furniture, and carpets. Their feces include enzymes that are released upon contact with a moist surface, which can happen when a person inhales, and these enzymes can kill cells within the human body.[3] House dust mites did not become a problem until humans began to use textiles, such as western style blankets and clothing.[4]


Presentation on imported dust in North American skies
Dust storm over Libya
Large dust storm over Libya

Atmospheric or wind-borne fugitive dust, also known as aeolian dust, comes from arid and dry regions where high velocity winds are able to remove mostly silt-sized material, deflating susceptible surfaces. This includes areas where grazing, ploughing, vehicle use, and other human activities have further destabilized the land, though not all source areas have been largely affected by anthropogenic impacts.[5] One-third of the global land area is covered by dust-producing surfaces, made up of hyper-arid regions like the Sahara which covers 0.9 billion hectares, and drylands which occupy 5.2 billion hectares.[6]

Dust in the atmosphere is produced by saltation and sandblasting of sand-sized grains, and it is transported through the troposphere. This airborne dust is considered an aerosol and once in the atmosphere, it can produce strong local radiative forcing. Saharan dust in particular can be transported and deposited as far as the Caribbean and the Amazon basin, and may affect air temperatures, cause ocean cooling, and alter rainfall amounts.[5]

Middle East

Dust in the Middle East has been a historic phenomenon. Recently, because of climate change and the escalating process of desertification, 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.

In Iran, the dust is already affecting more than 5 million people directly, and has emerged as a serious government issue in recent years. In the province of Khuzestan it has led to the severe reduction of air quality. The amount of pollutants 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 directly study the Middle Eastern dust.


Dust kicked up by vehicles traveling on roads[7] may make up 33% of air pollution.[8] Road dust consists of deposits of vehicle exhausts and industrial exhausts, particles from tire and brake wear, dust from paved roads or potholes, and dust from construction sites. Road dust is a significant source contributing to the generation and release of particulate matter into the atmosphere.[9] Control of road dust is a significant challenge in urban areas, and also in other locations with high levels of vehicular traffic upon unsealed roads, such as mines and landfill dumps.

Road dust may be suppressed by mechanical methods like street sweeper vehicles equipped with vacuum cleaners,[10] vegetable oil sprays,[11] or with water sprayers. Improvements in automotive engineering have reduced the amount of PM10s produced by road traffic; the proportion representing re-suspension of existing particulates has increased as a result.


Coal dust is responsible for the lung disease known as pneumoconiosis, including black lung disease that occurs among coal miners. The danger of coal dust resulted in environmental legislation regulating work place 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 create an explosion hazard under certain circumstances. These circumstances are typically within confined spaces.



Most governmental EPAs, including the United 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 obtain permits to conduct earth moving, clearing of areas, to include plans to control dust emissions when the work is being carried out. Control measures include such simple practices as spraying construction and demolition sites with water, and preventing the tracking of dust onto adjacent roads.

Some of the issues include:

  • Reducing dust related health risks that include allergic reactions, pneumonia and asthmatic attacks.
  • Improving visibility and road safety.
  • Providing cleaner air, cleaner vehicles and cleaner homes and promoting better health.
  • Improving crop productivity in agriculture.
  • Reducing vehicle maintenance costs by lowering the levels of dust that clog filters, bearings and machinery.
  • Reducing driver fatigue, maintenance on suspension systems and improving fuel economy.
  • Increasing cumulative effect - each new application builds on previous residuals reducing re-application rate *while improving performance.

US federal laws require dust control on sources such as vacant lots, unpaved parking lots, and unpaved roads. Dust in such places may be suppressed by mechanical methods, including paving or laying down gravel, or stabilizing the surface with water, vegetable oils[11] or other dust suppressants, or by using water misters to suppress dust that is already airborne.


Domestic Dust on a Ribbon
2014 Filtr powietrza DEMCiflex
Dust on the air filter
A video on reducing dust exposure in the workplace

Dust control is the suppression of solid particles with diameters less than 500 micrometers. Dust poses a health threat to children,[12] older people, and those with respiratory illnesses.

House dust can become airborne easily. Care is required when removing dust to avoid causing the dust to become airborne. A feather duster tends to agitate the dust so it lands elsewhere. Products like Pledge and Swiffer are specifically made for removing dust by trapping it with sticky chemicals.

Certified HEPA (tested to MIL STD 282) can effectively trap 99.97% of dust at 0.3 micrometers. Not all HEPA (type/media) filters can effectively stop dust; while vacuum cleaners with HEPA (type/media) 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 filtering appliances differ greatly in their effectiveness. 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 weighted filter and matched weight filters made from polyvinyl chloride or mixed cellulose ester are suitable for respirable dust (less than 10 micrometers in diameter).[13]

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 in manufacturing or through a repair process. A reduced tacticity of a synthetic layer or covering can protect surfaces and release small molecules that could have remained attached. A panel, container or enclosure with seams may feature types of strengthened rigidity or sealant to vulnerable edges and joins.

Outer space

Cosmic dust is widely present in space, where gas and dust clouds are primary precursors for planetary systems. The zodiacal light, as seen in a dark night sky, is produced by sunlight reflected from particles of dust in orbit around the Sun. The tails of comets are produced by emissions of dust and ionized gas from the body of the comet. Dust also covers solid planetary bodies, and vast dust storms occur on Mars that cover almost the entire planet. Interstellar dust is found between the stars, and high concentrations produce diffuse nebulae and reflection nebulae.

Dust is widely present in the galaxy. Ambient radiation heats dust and re-emits radiation into the microwave band, which may distort the cosmic microwave background power spectrum. Dust in this regime has a complicated emission spectrum, and includes both thermal dust emission and spinning dust emission.[14]

Dust samples returned from outer space may provide information about conditions in the early solar system. Several spacecraft have sought to gather samples of dust and other materials. Among these craft was Stardust, which flew past Comet Wild 2 in 2004, and returned a capsule of the comet's remains to Earth in January 2006. In 2010 the Japanese Hayabusa spacecraft returned samples of dust from the surface of an asteroid.

Atmospheric gallery

Dust over Southeast Australia

Dry, windy weather sends clouds of dust across south-eastern Australia.

Spring Bloom and Dust off Argentina

A pale brown plume of dust sweeps out of Argentina’s Pampas.

Dust Extends from Saudi Arabia to Iran

A thick dust plume over Kuwait and the north-western tip of the Persian Gulf.

See also


  1. ^ "Dust". Merriam-Webster. Archived from the original on 2017-03-14.
  2. ^ Hess-Kosa, Kathleen (2002). Indoor Air Quality: sampling methodologies. CRC Press. p. 216.
  3. ^ Abadi, Sara (August 2009). "The Great American Hygiene Survey Results Revealed". AOL Health. Archived from the original on 2009-08-26. Retrieved 2018-10-10.
  4. ^ Matthew J. Colloff, Dust Mites
  5. ^ a b Middleton, N. J.; Goudie, A. S. (2001). "Saharan dust: Sources and trajectories". Transactions of the Institute of British Geographers. 26 (2): 165. doi:10.1111/1475-5661.00013.
  6. ^ 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. (2005). "Global Iron Connections Between Desert Dust, Ocean Biogeochemistry, and Climate". Science. 308 (5718): 67–71. Bibcode:2005Sci...308...67J. CiteSeerX doi:10.1126/science.1105959. PMID 15802595.
  7. ^ "Road Dust - Something To Sneeze About". Sciencedaily.com. 1999-11-30. Archived from the original on 2012-10-30. Retrieved 2012-11-18.
  8. ^ [1] Archived July 11, 2011, at the Wayback Machine
  9. ^ "Environment Canada - Pollution and Waste - Tracking Pollution in Canada". Ec.gc.ca. 2012-07-05. Archived from the original on 2006-09-24. Retrieved 2012-11-18.
  10. ^ Peel, G.; Michielen, M.; Parker, G. (2001). "Some aspects of road sweeping vehicle automation". IEEE Xplore - Some aspects of road sweeping vehicle automation. 1. Ieeexplore.ieee.org. pp. 337–342. doi:10.1109/AIM.2001.936477. ISBN 978-0-7803-6736-4. Retrieved 2012-11-18.
  11. ^ a b "Questions and Answers: Road Dust Control with Soapstock-A Soybean Oil By- Product". Usroads.com. 1998-06-01. Archived from the original on 2013-01-11. Retrieved 2012-11-18.
  12. ^ "Dust mites in the humid atmosphere of Bangalore trigger around 60% of asthma" "Archived copy". Archived from the original on 2009-01-13. Retrieved 2008-10-03.CS1 maint: Archived copy as title (link)
  13. ^ Denger Dust Archived 2016-02-05 at the Wayback Machine
  14. ^ D. P. Finkbeiner, M. Davis and D. J. Schlegel (1999). "Extrapolation of Galactic Dust Emission at 100 Microns to CMBR Frequencies Using FIRAS". Astrophys. J. 524 (2): 867–886. arXiv:astro-ph/9905128. Bibcode:1999ApJ...524..867F. doi:10.1086/307852.


External links

Another One Bites the Dust

"Another One Bites the Dust" is a song by the British rock band Queen. Written by bass guitarist John Deacon, the song featured on the group's eighth studio album The Game (1980). The song was a worldwide hit, charting number one on the US Billboard Hot 100 for three weeks, from 4 October to 18 October (their second number-one single in the country). The song spent fifteen weeks in the Billboard top ten (the longest running top ten song of 1980), including thirteen weeks in the top five, and 31 weeks total on the chart (more than any other song in 1980). It reached number two on the Hot Soul Singles chart and the Disco Top 100 chart, and number seven on the UK Singles Chart. The song is credited as Queen's best-selling single, with sales of over 7 million copies. This version was ranked at number 34 on Billboard's All-Time Top Songs.The song won an American Music Award for Favorite Rock Single and also garnered a Grammy Award nomination for Best Rock Performance by a Duo or Group with Vocal. "Another One Bites the Dust" has been covered, remixed and sampled by many artists since its release, and has also appeared in TV shows, commercials, films and other media. The song is also commonly used at sports events, aimed at the losing opponent.

Asteroid belt

The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets. The asteroid belt is also termed the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System such as near-Earth asteroids and trojan asteroids. About half the mass of the belt is contained in the four largest asteroids: Ceres, Vesta, Pallas, and Hygiea. The total mass of the asteroid belt is approximately 4% that of the Moon, or 22% that of Pluto, and roughly twice that of Pluto's moon Charon (whose diameter is 1200 km).

Ceres, the asteroid belt's only dwarf planet, is about 950 km in diameter, whereas 4 Vesta, 2 Pallas, and 10 Hygiea have mean diameters of less than 600 km. The remaining bodies range down to the size of a dust particle. The asteroid material is so thinly distributed that numerous unmanned spacecraft have traversed it without incident. Nonetheless, collisions between large asteroids do occur, and these can produce an asteroid family whose members have similar orbital characteristics and compositions. Individual asteroids within the asteroid belt are categorized by their spectra, with most falling into three basic groups: carbonaceous (C-type), silicate (S-type), and metal-rich (M-type).

The asteroid belt formed from the primordial solar nebula as a group of planetesimals. Planetesimals are the smaller precursors of the protoplanets. Between Mars and Jupiter, however, gravitational perturbations from Jupiter imbued the protoplanets with too much orbital energy for them to accrete into a planet. Collisions became too violent, and instead of fusing together, the planetesimals and most of the protoplanets shattered. As a result, 99.9% of the asteroid belt's original mass was lost in the first 100 million years of the Solar System's history. Some fragments eventually found their way into the inner Solar System, leading to meteorite impacts with the inner planets. Asteroid orbits continue to be appreciably perturbed whenever their period of revolution about the Sun forms an orbital resonance with Jupiter. At these orbital distances, a Kirkwood gap occurs as they are swept into other orbits.Classes of small Solar System bodies in other regions are the near-Earth objects, the centaurs, the Kuiper belt objects, the scattered disc objects, the sednoids, and the Oort cloud objects.

On 22 January 2014, ESA scientists reported the detection, for the first definitive time, of water vapor on Ceres, the largest object in the asteroid belt. The detection was made by using the far-infrared abilities of the Herschel Space Observatory. The finding was unexpected because comets, not asteroids, are typically considered to "sprout jets and plumes". According to one of the scientists, "The lines are becoming more and more blurred between comets and asteroids."

Cosmic dust

Cosmic dust, also called extraterrestrial dust or space dust, is dust which exists in outer space, or has fallen on Earth. Most cosmic dust particles are between a few molecules to 0.1 µm in size. Cosmic dust can be further distinguished by its astronomical location: intergalactic dust, interstellar dust, interplanetary dust (such as in the zodiacal cloud) and circumplanetary dust (such as in a planetary ring).

In the Solar System, interplanetary dust causes the zodiacal light. Solar System dust includes comet dust, asteroidal dust, dust from the Kuiper belt, and interstellar dust passing through the Solar System. Thousands of tons of cosmic dust are estimated to reach the Earth's surface every year, with each grain having a mass between 10−16 kg (0.1 pg) and 10−4 kg (100 mg). The density of the dust cloud through which the Earth is traveling is approximately 10−6/m3.Cosmic dust contains some complex organic compounds (amorphous organic solids with a mixed aromatic–aliphatic structure) that could be created naturally, and rapidly, by stars. A smaller fraction of dust in space is "stardust" consisting of larger refractory minerals that condensed as matter left by stars.

Interstellar dust particles were collected by the Stardust spacecraft and samples were returned to Earth in 2006.

Dust Bowl

The Dust Bowl was a period of severe dust storms that greatly damaged the ecology and agriculture of the American and Canadian prairies during the 1930s; severe drought and a failure to apply dryland farming methods to prevent the aeolian processes (wind erosion) caused the phenomenon. The drought came in three waves, 1934, 1936, and 1939–1940, but some regions of the high plains experienced drought conditions for as many as eight years. With insufficient understanding of the ecology of the plains, farmers had conducted extensive deep plowing of the virgin topsoil of the Great Plains during the previous decade; this had displaced the native, deep-rooted grasses that normally trapped soil and moisture even during periods of drought and high winds. The rapid mechanization of farm equipment, especially small gasoline tractors, and widespread use of the combine harvester contributed to farmers' decisions to convert arid grassland (much of which received no more than 10 inches (~250 mm) of precipitation per year) to cultivated cropland.During the drought of the 1930s, the unanchored soil turned to dust, which the prevailing winds blew away in huge clouds that sometimes blackened the sky. These choking billows of dust – named "black blizzards" or "black rollers" – traveled cross country, reaching as far as the East Coast and striking such cities as New York City and Washington, D.C. On the plains, they often reduced visibility to 3 feet (1 m) or less. Associated Press reporter Robert E. Geiger happened to be in Boise City, Oklahoma, to witness the "Black Sunday" black blizzards of April 14, 1935; Edward Stanley, Kansas City news editor of the Associated Press coined the term "Dust Bowl" while rewriting Geiger's news story. While the term "the Dust Bowl" was originally a reference to the geographical area affected by the dust, today it usually refers to the event itself (the term "Dirty Thirties" is also sometimes used).

The drought and erosion of the Dust Bowl affected 100,000,000 acres (400,000 km2) that centered on the panhandles of Texas and Oklahoma and touched adjacent sections of New Mexico, Colorado, and Kansas.The Dust Bowl forced tens of thousands of poverty-stricken families to abandon their farms, unable to pay mortgages or grow crops, and losses reached $25 million per day by 1936 (equivalent to $450,000,000 in 2018). Many of these families, who were often known as "Okies" because so many of them came from Oklahoma, migrated to California and other states to find that the Great Depression had rendered economic conditions there little better than those they had left.

The Dust Bowl has been the subject of many cultural works, notably the novel The Grapes of Wrath (1939) by John Steinbeck, the folk music of Woody Guthrie, and photographs depicting the conditions of migrants by Dorothea Lange.

Dust devil

A dust devil is a strong, well-formed, and relatively long-lived whirlwind, ranging from small (half a metre wide and a few metres tall) to large (more than 10 metres wide and more than 1000 metres tall). The primary vertical motion is upward. Dust devils are usually harmless, but can on rare occasions grow large enough to pose a threat to both people and property.They are comparable to tornadoes in that both are a weather phenomenon involving a vertically oriented rotating column of wind. Most tornadoes are associated with a larger parent circulation, the mesocyclone on the back of a supercell thunderstorm. Dust devils form as a swirling updraft under sunny conditions during fair weather, rarely coming close to the intensity of a tornado.

Dust jacket

The dust jacket (sometimes book jacket, dust wrapper or dust cover) of a book is the detachable outer cover, usually made of paper and printed with text and illustrations. This outer cover has folded flaps that hold it to the front and back book covers. Often the back panel or flaps are printed with biographical information about the author, a summary of the book from the publisher (known as a blurb) or critical praise from celebrities or authorities in the book's subject area. In addition to its promotional role, the dust jacket protects the book covers from damage. However, since it is itself relatively fragile, and since dust jackets have practical, aesthetic and sometimes financial value, the jacket may in turn be wrapped in another jacket, usually transparent, especially if the book is a library volume.

Dust storm

A dust storm is a meteorological phenomenon common in arid and semi-arid regions. Dust storms arise when a gust front or other strong wind blows loose sand and dirt from a dry surface. Fine particles are transported by saltation and suspension, a process that moves soil from one place and deposits it in another.

Drylands around North Africa and the Arabian peninsula are the main terrestrial sources of airborne dust. It has been argued that poor management of the Earth's drylands, such as neglecting the fallow system, are increasing dust storms size and frequency from desert margins and changing both the local and global climate, and also impacting local economies.The term sandstorm is used most often in the context of desert dust storms, especially in the Sahara Desert, or places where sand is a more prevalent soil type than dirt or rock, when, in addition to fine particles obscuring visibility, a considerable amount of larger sand particles are blown closer to the surface. The term dust storm is more likely to be used when finer particles are blown long distances, especially when the dust storm affects urban areas.


A hardcover or hardback (also known as hardbound, and sometimes as case-bound) book is one bound with rigid protective covers (typically of Binder's board or heavy paperboard covered with buckram or other cloth, heavy paper, or occasionally leather). It has a flexible, sewn spine which allows the book to lie flat on a surface when opened. Following the ISBN sequence numbers, books of this type may be identified by the abbreviation Hbk.

Hardcover books are often printed on acid-free paper, and they are much more durable than paperbacks, which have flexible, easily damaged paper covers. Hardcover books are marginally more costly to manufacture. Hardcovers are frequently protected by artistic dust jackets, but a "jacketless" alternative is becoming increasingly popular: these "paper-over-board" or "jacketless hardcover" bindings forgo the dust jacket in favor of printing the cover design directly onto the board binding.

House dust mite

House dust mites (HDM, or simply dust mites) are a large number of mites found in association with dust in dwellings.The main species are identified as:

Dermatophagoides farinae (American house dust mite)

Dermatophagoides microceras

Dermatophagoides pteronyssinus (European house dust mite)

Euroglyphus maynei (Mayne's house dust mite)

Martian soil

Martian soil is the fine regolith found on the surface of Mars. Its properties can differ significantly from those of terrestrial soil, including its toxicity due to the presence of perchlorates. The term Martian soil typically refers to the finer fraction of regolith. On Earth, the term "soil" usually includes organic content. In contrast, planetary scientists adopt a functional definition of soil to distinguish it from rocks. Rocks generally refer to 10 cm scale and larger materials (e.g., fragments, breccia, and exposed outcrops) with high thermal inertia, with areal fractions consistent with the Viking Infrared Thermal Mapper (IRTM) data, and immobile under current aeolian conditions. Consequently, rocks classify as grains exceeding the size of cobbles on the Wentworth scale.

This approach enables agreement across Martian remote sensing methods that span the electromagnetic spectrum from gamma to radio waves. ‘‘Soil’’ refers to all other, typically unconsolidated, material including those sufficiently fine-grained to be mobilized by wind. Soil consequently encompasses a variety of regolith components identified at landing sites. Typical examples include: bedform armor, clasts, concretions, drift, dust, rocky fragments, and sand. The functional definition reinforces a recently proposed genetic definition of soil on terrestrial bodies (including asteroids and satellites) as an unconsolidated and chemically weathered surficial layer of fine-grained mineral or organic material exceeding centimeter scale thickness, with or without coarse elements and cemented portions.Martian dust generally connotes even finer materials than Martian soil, the fraction which is less than 30 micrometres in diameter. Disagreement over the significance of soil's definition arises due to the lack of an integrated concept of soil in the literature. The pragmatic definition "medium for plant growth" has been commonly adopted in the planetary science community but a more complex definition describes soil as "(bio)geochemically/physically altered material at the surface of a planetary body that encompasses surficial extraterrestrial telluric deposits." This definition emphasizes that soil is a body that retains information about its environmental history and that does not need the presence of life to form.


Nicotine is a stimulant and potent parasympathomimetic alkaloid that is naturally produced in the nightshade family of plants and used for the treatment of tobacco use disorders as a smoking cessation aid and nicotine dependence for the relief of withdrawal symptoms. Nicotine acts as a receptor agonist at most nicotinic acetylcholine receptors (nAChRs), except at two nicotinic receptor subunits (nAChRα9 and nAChRα10) where it acts as a receptor antagonist.Nicotine constitutes approximately 0.6–3.0% of the dry weight of tobacco. Usually consistent concentrations of nicotine varying from 2–7 µg/kg (20–70 millionths of a percent wet weight) are found in the edible family Solanaceae, such as potatoes, tomatoes, and eggplant. Some research indicates that the contribution of nicotine obtained from food is substantial in comparison to inhalation of second-hand smoke. Others consider nicotine obtained from food to be trivial unless exceedingly high amounts of certain vegetables are eaten. It functions as an antiherbivore chemical; consequently, nicotine was widely used as an insecticide in the past, and neonicotinoids, such as imidacloprid, are widely used.

Nicotine is highly addictive. It is one of the most commonly abused drugs. An average cigarette yields about 2 mg of absorbed nicotine; high amounts can be harmful. Nicotine induces both behavioral stimulation and anxiety in animals. Nicotine addiction involves drug-reinforced behavior, compulsive use, and relapse following abstinence. Nicotine dependence involves tolerance, sensitization, physical dependence, and psychological dependence. Nicotine dependency causes distress. Nicotine withdrawal symptoms include depressed mood, stress, anxiety, irritability, difficulty concentrating, and sleep disturbances. Mild nicotine withdrawal symptoms are measurable in unrestricted smokers, who experience normal moods only as their blood nicotine levels peak, with each cigarette. On quitting, withdrawal symptoms worsen sharply, then gradually improve to a normal state.Nicotine use as a tool for quitting smoking has a good safety history. The general medical position is that nicotine itself poses few health risks, except among certain vulnerable groups, such as youth. The International Agency for Research on Cancer indicates that nicotine does not cause cancer. Nicotine has been shown to produce birth defects in some animal species, but not others; consequently, it is considered to be a possible teratogen in humans. The median lethal dose of nicotine in humans is unknown, but high doses are known to cause nicotine poisoning.

Nuclear fallout

Nuclear fallout, or fallout, is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and the shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes. The amount and spread of fallout is a product of the size of the weapon and the altitude at which it is detonated. Fallout may get entrained with the products of a pyrocumulus cloud and fall as black rain (rain darkened by soot and other particulates).

This radioactive dust, usually consisting of fission products mixed with bystanding atoms that are neutron activated by exposure, is a highly dangerous kind of radioactive contamination.

Nutritional yeast

Nutritional yeast is a deactivated yeast, often a strain of Saccharomyces cerevisiae, which is sold commercially as a food product. It is sold in the form of flakes or as a yellow powder and can be found in the bulk aisle of most natural food stores. It is popular with vegans and vegetarians and may be used as an ingredient in recipes or as a condiment.It is a significant source of some B-complex vitamins and contains trace amounts of several other vitamins and minerals. Sometimes nutritional yeast is fortified with vitamin B12.

Nutritional yeast has a strong flavor that is described as nutty, cheesy, or creamy, which makes it popular as an ingredient in cheese substitutes. It is often used by vegans in place of cheese, for example in mashed and fried potatoes, in scrambled tofu, or as a topping for popcorn.In Australia, it is sometimes sold as "savoury yeast flakes." In New Zealand, it has long been known as Brufax. In the United States, it is sometimes referred to as "hippie dust" or "nooch". Though "nutritional yeast" usually refers to commercial products, inadequately fed prisoners of war have used "home-grown" yeast to prevent vitamin deficiency.

Nutritional yeast is different from yeast extract, which has a very strong flavour and comes in the form of a dark brown paste.

Opportunity (rover)

Opportunity, also known as MER-B (Mars Exploration Rover – B) or MER-1, and nicknamed "Oppy", is a robotic rover that was active on Mars from 2004 to late 2018. Launched on July 7, 2003, as part of NASA's Mars Exploration Rover program, it landed in Meridiani Planum on January 25, 2004, three weeks after its twin Spirit (MER-A) touched down on the other side of the planet. With a planned 90-sol duration of activity (slightly more than 90 Earth days), Spirit functioned until it got stuck in 2009 and ceased communications in 2010, while Opportunity was able to stay operational for 5111 sols after landing, maintaining its power and key systems through continual recharging of its batteries using solar power, and hibernating during events such as dust storms to save power. This careful operation allowed Opportunity to exceed its operating plan by 14 years, 46 days (in Earth time), 55 times its designed lifespan. By June 10, 2018, when it last contacted NASA, the rover had traveled a distance of 45.16 kilometers (28.06 miles).Mission highlights included the initial 90-sol mission, finding extramartian meteorites such as Heat Shield Rock (Meridiani Planum meteorite), and over two years of exploring and studying Victoria crater. The rover survived moderate dust storms and in 2011 reached Endeavour crater, which has been described as a "second landing site". The Opportunity mission is considered one of NASA's most successful ventures.Due to the planetary 2018 dust storm on Mars, Opportunity ceased communications on June 10 and entered hibernation on June 12, 2018. It was hoped it would reboot once the weather cleared, but it did not, suggesting either a catastrophic failure or that a layer of dust had covered its solar panels. NASA hoped to re-establish contact with the rover, citing a windy period that could potentially clean off its solar panels. On February 13, 2019, NASA officials declared that the Opportunity mission was complete, after the spacecraft had failed to respond to over 1,000 signals sent since August 2018.


Sawdust or wood dust is a by-product or waste product of woodworking operations such as sawing, milling, planing, routing, drilling and sanding. It is composed of fine particles of wood. These operations can be performed by woodworking machinery, portable power tools or by use of hand tools. Wood dust is also the byproduct of certain animals, birds and insects which live in wood, such as the woodpecker and carpenter ant. In some manufacturing industries it can be a significant fire hazard and source of occupational dust exposure.

Sawdust is the main component of particleboard. Wood dust is a form of particulate matter, or particulates. Research on wood dust health hazards comes within the field of occupational health science, and study of wood dust control comes within the field of indoor air quality engineering.


Silicosis (also known as miner's phthisis, grinder's asthma, potter's rot and other occupation-related names, or by the invented name pneumonoultramicroscopicsilicovolcanoconiosis) is a form of occupational lung disease caused by inhalation of crystalline silica dust, and is marked by inflammation and scarring in the form of nodular lesions in the upper lobes of the lungs. It is a type of pneumoconiosis.Silicosis (particularly the acute form) is characterized by shortness of breath, cough, fever, and cyanosis (bluish skin). It may often be misdiagnosed as pulmonary edema (fluid in the lungs), pneumonia, or tuberculosis.

Silicosis resulted in 46,000 deaths globally in 2013 down from 55,000 deaths in 1990.The name silicosis (from the Latin silex, or flint) was originally used in 1870 by Achille Visconti (1836–1911), prosector in the Ospedale Maggiore of Milan. The recognition of respiratory problems from breathing in dust dates to ancient Greeks and Romans. Agricola, in the mid-16th century, wrote about lung problems from dust inhalation in miners. In 1713, Bernardino Ramazzini noted asthmatic symptoms and sand-like substances in the lungs of stone cutters. With industrialization, as opposed to hand tools, came increased production of dust. The pneumatic hammer drill was introduced in 1897 and sandblasting was introduced in about 1904, both significantly contributing to the increased prevalence of silicosis.

Tinker Bell

Tinker Bell is a fictional character from J. M. Barrie's 1904 play Peter Pan and its 1911 novelization Peter and Wendy. She has appeared in multiple film and television adaptations of the Peter Pan stories, in particular the 1953 animated Walt Disney picture Peter Pan. She also appears in the official sequel Peter Pan in Scarlet by Geraldine McCaughrean commissioned by Great Ormond Street Hospital as well as the "Peter and the Starcatchers" book series by Ridley Pearson and Dave Barry.

At first only a supporting character described by her creator as "a common fairy", her animated incarnation was a hit and has since become a widely recognized unofficial mascot of The Walt Disney Company, and the centrepiece of its Disney Fairies media franchise including the direct-to-DVD film series Tinker Bell and Walt Disney's Wonderful World of Color.

Vacuum cleaner

A vacuum cleaner, also known as a sweeper or hoover, is a device that uses an air pump (a centrifugal fan in all but some of the very oldest models), to create a partial vacuum to suck up dust and dirt from floors and from other surfaces such as upholstery and draperies.

The dirt is collected by either a dustbag or a cyclone for later disposal. Vacuum cleaners, which are used in homes as well as in industry, exist in a variety of sizes and models—small battery-powered hand-held devices, wheeled canister models for home use, domestic central vacuum cleaners, huge stationary industrial appliances that can handle several hundred litres of dust before being emptied, and self-propelled vacuum trucks for recovery of large spills or removal of contaminated soil. Specialized shop vacuums can be used to suck up both dust and liquids.

Waste container

A waste container is a container for temporarily storing waste, and is usually made out of metal or plastic. Some common terms are dustbin, garbage can, and trash can. The words "rubbish", "basket" and "bin" are more common in British English usage; "trash" and "can" are more common in American English usage. "Garbage" may refer to food waste specifically (when distinguished from "trash") or to municipal solid waste in general. In 1875, the first household rubbish bins were introduced in Britain to create a regulated system of collection.

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