86 astatine ← radon → francium Xe ↑ Rn ↓ Uuo Periodic Table - Extended Periodic Table
General
Name, Symbol, Number	radon, Rn, 86
Chemical series	noble gases
Group, Period, Block	18, 6, p
Appearance	colorless
Standard atomic weight	(222) g·mol−1
Electron configuration	[Xe] 4f14 5d10 6s2 6p6
Electrons per shell	2, 8, 18, 32, 18, 8
Physical properties
Phase	gas
Density	(0 °C, 101.325 kPa) 9.73 g/L
Melting point	202 K (−71.15 °C, −96 °F)
Boiling point	211.3 K (−61.85 °C, −79.1 °F)
Critical point	377 K, 6.28 MPa
Heat of fusion	3.247 kJ·mol−1
Heat of vaporization	18.10 kJ·mol−1
Heat capacity	(25 °C) 20.786 J·mol−1·K−1
Vapor pressure P(Pa) 1 10 100 1 k 10 k 100 k at T(K) 110 121 134 152 176 211
Atomic properties
Crystal structure	cubic face centered
Oxidation states	0
Electronegativity	no data (scale Pauling)
Ionization energies	1st: 1037 kJ/mol
Atomic radius (calc.)	120 pm
Covalent radius	145 pm
Miscellaneous
Magnetic ordering	non-magnetic
Thermal conductivity	(300 K) 3.61 m W·m−1·K−1
CAS registry number	10043-92-2
Selected isotopes
Main article: Isotopes of radon iso NA half-life DM DE (MeV) DP 211Rn syn 14.6 h Epsilon 2.892 211At Alpha 5.965 207Po 222Rn 100% 3.824 d Alpha 5.590 218Po
References

Radon (pronounced /ˈreɪdɒn/) is a chemical element that has the symbol Rn and atomic number 86. Radon is a radioactive noble gas that is formed by the decay of radium. It is one of the heaviest gases and is considered to be a health hazard. The most stable isotope is ²²²Rn which has a half-life of 3.8 days and is used in radiotherapy. Radon is a significant contaminant that affects indoor air quality worldwide. Radon gas from natural sources can accumulate in buildings and reportedly causes 21,000 lung cancer deaths per year in the United States alone.^[1] Radon is a chemical element. ... General Name, Symbol, Number astatine, At, 85 Chemical series halogens Group, Period, Block 17, 6, p Appearance metallic (presumed) Standard atomic weight (210) g·mol−1 Electron configuration [Xe] 4f14 5d10 6s2 6p5 Electrons per shell 2, 8, 18, 32, 18, 7 Physical properties Phase solid Melting point 575 K... General Name, Symbol, Number francium, Fr, 87 Chemical series alkali metals Group, Period, Block 1, 7, s Appearance metallic Atomic mass (223) g·mol−1 Electron configuration [Rn] 7s1 Electrons per shell 2, 8, 18, 32, 18, 8, 1 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number xenon, Xe, 54 Chemical series noble gases Group, Period, Block 18, 5, p Appearance colorless Standard atomic weight 131. ... General Name, Symbol, Number ununoctium, Uuo, 118 Chemical series noble gases Group, Period, Block 18, 7, p Appearance unknown, probably colorless Atomic mass predicted, (314) g/mol Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p6 (guess based on radon) Electrons per shell 2, 8, 18, 32, 32, 18, 8 Phase... File links The following pages link to this file: Radon User:Femto/elements e7 Categories: GFDL images ... This is a standard display of the periodic table of the elements. ... An extended periodic table was suggested by Glenn T. Seaborg in 1969. ... This is a list of chemical elements, sorted by name and color coded according to type of element. ... A table of chemical elements ordered by atomic number and color coded according to type of element. ... A group, also known as a family, is a vertical column in the periodic table of the chemical elements. ... This article is about the chemical series. ... A group, also known as a family, is a vertical column in the periodic table of the chemical elements. ... In the periodic table of the elements, a period is a horizontal row of the table. ... A block of the periodic table of elements is a set of adjacent groups. ... The noble gases are a chemical series. ... A period 6 element is one of the chemical elements in the sixth row (or period) of the periodic table of the elements, including the Lanthanides. ... The p-block of the periodic table of elements consists of the last six groups. ... Color is an important part of the visual arts. ... The atomic mass (ma) is the mass of an atom at rest, most often expressed in unified atomic mass units. ... To help compare different orders of magnitude we list here masses between 60. ... Electron atomic and molecular orbitals In atomic physics and quantum chemistry, the electron configuration is the arrangement of electrons in an atom, molecule, or other physical structure (, a crystal). ... General Name, Symbol, Number xenon, Xe, 54 Chemical series noble gases Group, Period, Block 18, 5, p Appearance colorless Standard atomic weight 131. ... For other uses, see Electron (disambiguation). ... Example of a sodium electron shell model An electron shell, also known as a main energy level, is a group of atomic orbitals with the same value of the principal quantum number n. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... Gas can also refer to gasoline and natural gas and also hydrogen. ... For other uses, see Density (disambiguation). ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ... For other uses, see Kelvin (disambiguation). ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... For other uses, see Fahrenheit (disambiguation). ... Italic text This article is about the boiling point of liquids. ... For other uses, see Kelvin (disambiguation). ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... For other uses, see Fahrenheit (disambiguation). ... In physical chemistry, thermodynamics, chemistry and condensed matter physics, a critical point, also called a critical state, specifies the conditions (temperature, pressure) at which the liquid state of the matter ceases to exist. ... For other uses, see Kelvin (disambiguation). ... Standard enthalpy change of fusion of period three. ... The joule per mole (symbol: J·mol-1) is an SI derived unit of energy per amount of material. ... The standard enthalpy change of vaporization, ΔvHo, also (less correctly) known as the heat of vaporization is the energy required to transform a given quantity of a substance into a gas. ... The joule per mole (symbol: J·mol-1) is an SI derived unit of energy per amount of material. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. ... Enargite crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... The oxidation number of an element in a molecule or complex is the charge that it would have if all the ligands (basically, atoms that donate electrons) were removed along with the electron pairs that were shared with the central atom[1]. It means that the oxidation number is the... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... The ionization energy (IE) of an atom or of a molecule is the energy required to strip it of an electron. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... You have big harry skanky balls ... Atomic radius: Ionic radius Covalent radius Metallic radius van der Waals radius edit The covalent radius, rcov, is a measure of the size of atom which forms part of a covalent bond. ... You have big harry skanky balls ... For other senses of this word, see magnetism (disambiguation). ... K value redirects here. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... There are twenty known isotopes of Radon (Rn). ... For other uses, see Isotope (disambiguation). ... Natural abundance refers to the prevalence of different isotopes of an element as found in nature. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. ... The decay energy is the energy released by a nuclear decay. ... The electronvolt (symbol eV) is a unit of energy. ... In nuclear physics, a decay product, also known as a daughter product, is a nuclide resulting from the radioactive decay of a parent or precursor nuclide. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... The hour (symbol: h) is a unit of time. ... Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron... General Name, Symbol, Number astatine, At, 85 Chemical series halogens Group, Period, Block 17, 6, p Appearance metallic (presumed) Standard atomic weight (210) g·mol−1 Electron configuration [Xe] 4f14 5d10 6s2 6p5 Electrons per shell 2, 8, 18, 32, 18, 7 Physical properties Phase solid Melting point 575 K... Alpha decay is a form of radioactive decay in which an atomic nucleus ejects an alpha particle and transforms into a nucleus with mass number 4 less and atomic number 2 less. ... General Name, Symbol, Number polonium, Po, 84 Chemical series metalloids Group, Period, Block 16, 6, p Appearance silvery Standard atomic weight (209) g·mol−1 Electron configuration [Xe] 4f14 5d10 6s2 6p4 Electrons per shell 2, 8, 18, 32, 18, 6 Physical properties Phase solid Density (near r. ... Look up day in Wiktionary, the free dictionary. ... General Name, Symbol, Number polonium, Po, 84 Chemical series metalloids Group, Period, Block 16, 6, p Appearance silvery Standard atomic weight (209) g·mol−1 Electron configuration [Xe] 4f14 5d10 6s2 6p4 Electrons per shell 2, 8, 18, 32, 18, 6 Physical properties Phase solid Density (near r. ... Recommended values for many properties of the elements, together with various references, are collected on these data pages. ... The periodic table of the chemical elements A chemical element, or element, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... See also: List of elements by atomic number In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... This article is about the chemical series. ... General Name, Symbol, Number radium, Ra, 88 Chemical series alkaline earth metals Group, Period, Block 2, 7, s Appearance silvery white metallic Standard atomic weight (226) g·mol−1 Electron configuration [Rn] 7s2 Electrons per shell 2, 8, 18, 32, 18, 8, 2 Physical properties Phase solid Density (near r. ... For other uses, see Isotope (disambiguation). ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). ... Indoor Air Quality (IAQ) deals with the content of interior air that could affect health and comfort of building occupants. ...

Notable characteristics

Essentially chemically inert but radioactive, radon is the heaviest noble gas and one of the heaviest gases at room temperature. At standard temperature and pressure radon is a colorless gas, but when it is cooled below its freezing point (202 K ; −71 °C ; −96 °F) it has a brilliant phosphorescence which turns yellow as the temperature is lowered, and becomes orange-red at the temperatures air liquefies (below 93 K ; −180 °C). This article is about the chemical series. ... Temperature and air pressure can vary from one place to another on the Earth, and can also vary in the same place with time. ... Freezing point can refer to several things: For the chemistry term, see Melting point. ... A yellow Tulip. ... The orange, the fruit from which the modern name of the orange colour comes. ... For other uses, see Red (disambiguation). ...

Natural radon concentrations in Earth's atmosphere are so low that radon-rich water in contact with the atmosphere will continually lose radon by volatilization. Hence, ground water has a higher concentration of ²²²Rn than surface water, because it is continuously produced by radioactive decay of ²²⁶Ra present in rocks. Likewise, the saturated zone of a soil frequently has a higher radon content than the unsaturated zone because of diffusional losses to the atmosphere. Air redirects here. ... Volatilisation is the process whereby a dissolved sample is vaporised. ... Groundwater is any water found below the land surface. ... Surface water is water on the ground or in a stream, river, lake, sea or ocean; as opposed to groundwater. ... General Name, Symbol, Number radium, Ra, 88 Chemical series alkaline earth metals Group, Period, Block 2, 7, s Appearance silvery white metallic Standard atomic weight (226) g·mol−1 Electron configuration [Rn] 7s2 Electrons per shell 2, 8, 18, 32, 18, 8, 2 Physical properties Phase solid Density (near r. ...

History

Radon (named after radium) was discovered in 1900 by Friedrich Ernst Dorn, who called it radium emanation. In 1908 William Ramsay and Robert Whytlaw-Gray, named it niton (Latin nitens meaning "shining"; symbol Nt) and isolated it, determined its density, and determined that it was the heaviest known gas. It has been called "radon" since 1923. Friedrich Ernst Dorn (1848-1916) was a German physicist who discovered radon in 1898. ... Sir William Ramsay (October 2, 1852 – July 23, 1916) was a Scottish chemist who discovered the noble gases and received the Nobel Prize in Chemistry in 1904 (along with Lord Rayleigh who received the Nobel Prize in Physics that same year for the discovery of argon). ... Robert Whytlaw-Gray (1877-1958) was a chemist, born in Guttstadt, Germany. ... For other uses, see Latin (disambiguation). ... Gas can also refer to gasoline and natural gas and also hydrogen. ...

The first major studies of the health concern occurred in the context of uranium mining, first in the Joachimsthal region of Bohemia and then in the Southwestern United States during the early Cold War. Because radon is a product of uranium, uranium mines may have high concentrations of radon and its highly radioactive daughter products. Many uranium miners in the Four Corners region contracted lung cancer and other pathologies as a result of high levels of exposure to radon in the mid-1950s. The increased incidence of lung cancer was particularly pronounced among Native American and Mormon miners, because those goups normally have low rates of lung cancer. Safety standards requiring expensive ventilation were not widely implemented or policed during that period. Jáchymov (originally Thal, later Sankt Joachimsthal in German) is a spa town in the Czech Republic, located at the St. ... Flag of Bohemia Bohemia (Czech: ; German: ) is a historical region in central Europe, occupying the western and middle thirds of the Czech Republic. ... Regional definitions vary from source to source. ... For other uses, see Cold War (disambiguation). ... Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. ... Four Corners may refer to one of the following: Four Corners, a region of the United States the Four Corners Monument at that location Four Corners, a point in Canada Four Corners, an Australian news program Four Corners, a movie by James Benning four corners offense, a style of basketball... Lung cancer is the malignant transformation and expansion of lung tissue, and is the most lethal of all cancers worldwide, responsible for 1. ... This article is about the people indigenous to the United States. ... This article is about the history and use of the word Mormon. For information about the religious beliefs and culture of Mormons, see Mormonism. ...

The danger of radon exposure in dwellings was discovered in 1984 with the case of Stanley Watras, an employee at the Limerick nuclear power plant in Pennsylvania. Watras set off the radiation alarms on his way into work for two weeks straight while authorities searched for the source of the contamination. They were shocked to find that the source was astonishingly high levels of radon, around 100,000 Bq/m³ (2,700 pCi/L), in his house's basement and it was not related to the nuclear plant. The risks associated with living in his house were estimated to be equivalent to smoking 135 packs of cigarettes every day. Following this event, which was highly publicized, national radon safety standards were set, and radon detection and ventilation became a standard homeowner concern. The Limerick nuclear power facility in Pennsylvania has two General Electric boiling water reactor (BWR) units, cooled by natural draft cooling towers. ... Capital Harrisburg Largest city Philadelphia Largest metro area Delaware Valley Area  Ranked 33rd  - Total 46,055 sq mi (119,283 km²)  - Width 280 miles (455 km)  - Length 160 miles (255 km)  - % water 2. ... This article or section does not cite any references or sources. ... The becquerel (symbol Bq) is the SI derived unit of radioactivity, defined as the activity of a quantity of radioactive material in which one nucleus decays per second. ... The curie (symbol Ci) is a former unit of radioactivity, defined as 3. ... A townhouse with basement windows showing A basement is one or more floors of a building that are either completely or partially below the ground floor. ... The cigarette is the most common method of smoking tobacco. ... Two unlit filtered cigarettes. ...

Radon is the second most frequent cause of lung cancer, after cigarette smoking, and radon-induced lung cancer is thought to be the 6th leading cause of cancer death overall.^[2][3]

Occurrence

On average, there is one atom of radon in 1 x 10²¹ molecules of air.^{[citation needed]} Radon can be found in some spring waters and hot springs.^[4] The towns of Boulder, Montana, Misasa, Japan, and Bad Kreuznach, Germany boast radium-rich springs which emit radon. A natural spring on Mackinac Island in Michigan. ... Green Dragon Spring at Norris Geyser A hot spring is a place where warm or hot groundwater issues from the ground on a regular basis for at least a predictable part of the year, and is significantly above the ambient ground temperature (which is usually around 55~57 F or... Boulder is a town in Jefferson County, Montana, United States. ... Misasa (三朝町; -cho) is a town located in Tōhaku District, Tottori, Japan. ... Bad Kreuznach is the capital of Bad Kreuznach (district), Rheinland-Pfalz, Germany. ...

Radon emanates naturally from the ground all over the world, particularly in regions with soils containing granite or shale. However, not all granitic regions are prone to high emissions of radon. Depending on how houses are built and ventilated, radon may accumulate in basements and dwellings. The highest average radon concentrations in counties in the U.S. are found in Iowa and in the Appalachian Mountain areas in southeastern Pennsylvania. ^[5] Some of the highest readings ever have been recorded in the Irish town of Mallow, County Cork prompting local fears regarding lung cancer. For other uses, see granite (disambiguation). ... Shale Shale is a fine-grained sedimentary rock whose original constituents were clays or muds. ... Official language(s) English Capital Des Moines Largest city Des Moines Area  Ranked 26th  - Total 56,272 sq mi (145,743 km²)  - Width 310 miles (500 km)  - Length 199 miles (320 km)  - % water 0. ... The Appalachian Mountains are a vast system of mountains in eastern North America. ... WGS-84 (GPS) Coordinates: , Irish Grid Reference W549982 Statistics Province: Munster County: Elevation: 74 m (242 ft) Population (2006) 7,864  Website: www. ...

Radon, along with other noble gases krypton and xenon, is also produced during the operation of nuclear power plants. A small fraction of it leaks out of the fuel, through the cladding and into the cooling water, from which it is scavenged. It is then routed to a holding tank where it remains for a large number of half-lives. It is finally purged to the open air through a tall stack which is carefully monitored for radiation level. For other uses, see Krypton (disambiguation). ... General Name, Symbol, Number xenon, Xe, 54 Chemical series noble gases Group, Period, Block 18, 5, p Appearance colorless Standard atomic weight 131. ... A nuclear power plant (NPP) is a thermal power station in which the heat source is one or more nuclear reactors. ...

The European Union recommends that action should be taken starting from concentrations of 400 Bq/m³ (11 pCi/L) for old houses and 200 Bq/m³ (5 pCi/L) for new ones. After publication of the North American and European Pooling Studies, Health Canada has proposed a new guideline that lowers their action level from 800 to 200 Bq/m³ (22 to 5 pCi/L).^[6] The United States Environmental Protection Agency (EPA) strongly recommends action for any house with a concentration higher than 148 Bq/m³ (4 pCi/L)^[7], and encourages action starting at 74 Bq/m³ (2 pCi/L). EPA radon risk level tables including comparisons to other risks encountered in life are available in their citizen's guide.^[8] Nearly one in 15 homes in the U.S. has a high level of indoor radon according to their statistics. The U.S. Surgeon General and EPA recommend all homes be tested for radon. sex Canada (French: Santé Canada) is the department of the government of Canada with responsibility for national public health. ... EPA redirects here. ... The curie (symbol Ci) is a former unit of radioactivity, defined as 3. ... The curie (symbol Ci) is a former unit of radioactivity, defined as 3. ...

Radon emitted from the ground has been shown to accumulate in the air if there is a meteorological inversion and little wind.^[9]

Compounds

Some experiments indicate that fluorine can react with radon and form radon fluoride. Radon clathrates have also been reported. Distinguished from fluorene and fluorone. ... Radon fluoride (RnF) is a compound of radon, an inert or noble gas. ... A clathrate or clathrate compound is a chemical substance consisting of a Greek klethra, meaning bars (in the sense of a lattice). ...

Isotopes

Main article: isotopes of radon

There are twenty known isotopes of radon. The most stable isotope is ²²²Rn, which is a decay product (daughter product) of ²²⁶Ra, has a half-life of 3.823 days and emits alpha particles. ²²⁰Rn is a natural decay product of thorium and is called “thoron.” It has a half-life of 55.6 seconds and also emits alpha radiation. ²¹⁹Rn is derived from actinium, is called “actinon,” is an alpha emitter and has a half-life of 3.96 seconds. There are twenty known isotopes of Radon (Rn). ... For other uses, see Isotope (disambiguation). ... In nuclear physics, a decay product, also known as a daughter product, is a nuclide resulting from the radioactive decay of a parent or precursor nuclide. ... In nuclear physics, a decay product, also known as a daughter product, is a nuclide resulting from the radioactive decay of a parent or precursor nuclide. ... An alpha particle is deflected by a magnetic field Alpha radiation consists of helium-4 nuclei and is readily stopped by a sheet of paper. ... General Name, Symbol, Number thorium, Th, 90 Chemical series Actinides Group, Period, Block n/a, 7, f Appearance silvery white Standard atomic weight 232. ... General Name, Symbol, Number actinium, Ac, 89 Chemical series actinides Group, Period, Block 3, 7, f Appearance silvery Atomic mass (227) g·mol−1 Electron configuration [Rn] 6d1 7s2 Electrons per shell 2, 8, 18, 32, 18, 9, 2 Physical properties Phase solid Density (near r. ...

The full decay series of ²³⁸U which produces natural radon is as follows (with half-lives):

²³⁸U (4.5 x 10⁹ yr), ²³⁴Th (24.1 days), ²³⁴Pa (1.18 min), ²³⁴U (250,000 yr), ²³⁰Th (75,000 yr), ²²⁶Ra (1,600 yr), ²²²Rn (3.82 days), ²¹⁸Po (3.1 min), ²¹⁴Pb (26.8 min), ²¹⁴Bi (19.7 min), ²¹⁴Po (164 µs), ²¹⁰Pb (22.3 yr), ²¹⁰Bi (5.01 days), ²¹⁰Po (138 days), ²⁰⁶Pb (stable).

Nearly all the decay products of radioactive decay are themselves radioactive. ... There are two objects with this name: Unterseeboot 238 Uranium-238, the most common isotope of uranium This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... General Name, Symbol, Number thorium, Th, 90 Chemical series Actinides Group, Period, Block n/a, 7, f Appearance silvery white Standard atomic weight 232. ... General Name, Symbol, Number protactinium, Pa, 91 Chemical series actinides Group, Period, Block n/a, 7, f Appearance bright, silvery metallic luster Standard atomic weight 231. ... U-234 is an isotope of uranium. ... Thorium (Th) Standard atomic mass: 232. ... General Name, Symbol, Number radium, Ra, 88 Chemical series alkaline earth metals Group, Period, Block 2, 7, s Appearance silvery white metallic Standard atomic weight (226) g·mol−1 Electron configuration [Rn] 7s2 Electrons per shell 2, 8, 18, 32, 18, 8, 2 Physical properties Phase solid Density (near r. ... Polonium (Po) Has no stable isotopes. ... Lead (Pb) Standard atomic mass: 207. ... Bismuth (Bi) Standard atomic mass: 208. ...

Applications

Radon therapy

In the United States and Europe there are a few "radon spas," where people sit for minutes or hours in a high-radon atmosphere in the belief that low doses of radiation will invigorate or energize them. In addition personal testimonies of arthritis relief and other benefits, there is some (very limited) scientific evidence for this belief, known as hormesis. However, the general scientific community finds it unsubstantiated. There is no known biological mechanism by which such an effect could occur. In addition, it conflicts with the internationally recognized standard that there is no safe threshold for radiation exposure and that exposure should be limited to that "as low as reasonably achievable" (ALARA). A destination spa is a business establishment which people visit for personal health, life enhancement, fitness, personal care treatments such as massages, facials, in a resort setting. ... Radiation hormesis is the theory that low doses of ionizing radiation are beneficial. ... The linear no-threshold model or LNTM is a model of the damage cased by ionizing radiation, and particularly the increased risk of cancer. ... ALARA Alara king of Nubia The unifier of Kush and grandfather of king Taharqa ...

Radioactive water baths have been applied since 1906 in Jáchymov, Czech Republic, but even before radon discovery they were used in Bad Gastein, Austria. Hot radium-rich spring releasing radon is also used in traditional Japanese onsen in Misasa, Tottori prefecture. Drinking therapy is applied in Bad Brambach, Germany. Inhalation therapy is carried out in Gasteiner-Heilstollen, Austria, in Kowary, Poland and in Boulder, Montana, United States. Spa at the beginning of 20th century, photographed by Å echtl and Voseček For other places called Joachimsthal, see Joachimsthal (disambiguation) Jáchymov (IPA: ; in German originally Thal, later Sankt Joachimsthal or Joachimsthal, as it is also known in English) is a spa town in north-west Bohemia in the... Bad Gastein Bad Gastein is a city in Austria, situated in the middle of the National Park Hohe Tauern, at 1,000 metres above sea level, in fresh mountain air. ... Outdoor pool, Naruko, Miyagi Guidebook to Hakone from 1811 An onsen ) is a Japanese hot spring. ... Misasa (三朝町; -cho) is a town located in Tōhaku District, Tottori, Japan. ... Tottori (鳥取市; -shi) is the capital city of Tottori Prefecture in the Chugoku region of Japan. ... Bad Brambach is a municipality in the Vogtlandkreis district, in Saxony, Germany. ... Center of the town in winter Kowary (German: ) is a town in Jelenia Góra County, Lower Silesian Voivodeship, Poland, with 11,965 inhabitants (2004). ... Boulder is a town in Jefferson County, Montana, United States. ...

Hydrologic studies

Because of radon's rapid loss to air and comparatively rapid decay, radon is used in hydrologic research that studies the interaction between ground water and streams. Any significant concentration of radon in a stream is a good indicator that there are local inputs of ground water. Water covers 70% of the Earths surface. ... Butchers Creek, Omeo, Victoria A stream, brook, beck, burn or creek, is a body of water with a detectable current, confined within a bed and banks. ...

Geologic studies

Some researchers have looked at elevated soil-gas radon concentrations, or rapid changes in soil or groundwater radon concentrations, as a predictor for earthquakes. Results have been generally unconvincing but may ultimately prove to have some limited use in specific locations. This article is about the natural seismic phenomenon. ...

Radon soil-concentration has been used in an experimental way to map buried close-subsurface geological faults, because concentrations are generally higher over the faults. Similarly it has found some limited use in geothermal prospecting.

Atmospheric studies

Radon emanation from the soil varies with soil type and with surface uranium content, so outdoor radon concentrations can be used to track air masses to a limited degree. This fact has been put to use by some atmospheric scientists.

Radon is a known pollutant emitted from geothermal power stations, though it disperses rapidly, and no radiological hazard has been demonstrated in various investigations. The trend in geothermal plants is to reinject all emissions by pumping deep underground, and this seems likely to ultimately decrease such radon hazards further. Radon is also used in dating of oil contained soil because radon have a high affinity of oil like substance.

Health effects and epidemiology

The general effects of radon to the human body are caused by its radioactivity and consequent risk of radiation-induced cancer. As an inert gas, radon has a low solubility in body fluids which lead to a uniform distribution of the gas throughout the body.^[10] Radon gas and its solid decay products are carcinogens. The greatest health risks come from exposure to the inhaled solid radon gas decay products that are produced during the radioactive decay of radon gas. Two of these decay products, polonium-218 and 214, present a significant radiologic hazard.^[11] Once the radioactive decay products are inhaled into the lung, they undergo further radioactive decay, releasing small bursts of energy in the form of alpha particles that can either cause DNA breaks or create free radicals.^[11] The hazard symbol for carcinogenic chemicals in the Globally Harmonized System. ... General Name, Symbol, Number polonium, Po, 84 Chemical series metalloids Group, Period, Block 16, 6, p Appearance silvery Standard atomic weight (209) g·mol−1 Electron configuration [Xe] 4f14 5d10 6s2 6p4 Electrons per shell 2, 8, 18, 32, 18, 6 Physical properties Phase solid Density (near r. ... An alpha particle is deflected by a magnetic field Alpha particles or alpha rays are a form of particle radiation which are highly ionizing and have low penetration. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... In chemistry free radicals are uncharged atomic or molecular species with unpaired electrons or an otherwise open shell configuration. ...

Based on studies carried out by the National Academy of Sciences in the United States, radon is the second most common cause of lung cancer after cigarette smoking, accounting for 15,000 to 22,000 cancer deaths per year in the U.S.^[12] The Surgeon General of the United States has reported that over 20,000 Americans die each year of radon-related lung cancer.^[13] The United States Environmental Protection Agency (EPA) recommends homes be fixed if an occupant's long-term exposure will average 4 picocuries per liter (pCi/L) (148 Bq m⁻³) or higher.^[14] President Harding and the National Academy of Sciences at the White House, Washington, DC, April 1921 The National Academy of Sciences (NAS) is a corporation in the United States whose members serve pro bono as advisers to the nation on science, engineering, and medicine. ... US Public Health Service US Public Health Service Collar Device US Public Health Service Cap Device The Surgeon General of the United States is the head of the United States Public Health Service Commissioned Corps (PHSCC) and thus the leading spokesperson on matters of public health in the U.S... EPA redirects here. ... The curie (symbol Ci) is a former unit of radioactivity, defined as 3. ...

The most elaborate case-control epidemiologic radon study performed by R. William Field and colleagues demonstrated a 50% increased lung cancer risk with prolonged radon exposure at the EPA's action level of 4 pCi/L.^[15] Iowa has the highest average radon concentrations in the nation and a very stable population which added to the strength of the study. Pooled epidemiologic radon studies^[16][17] have also shown an increased lung cancer risk from radon below the EPA's action level of 4 pCi/L. R. William Field is an American Academic Associate Professor in the Department of Occupational and Environmental Health and Department of Epidemiology at the University of Iowa. ...

It is unknown whether radon causes other types of cancer, but recent studies suggest a need for further studies to assess the relationship between radon and leukemia.^[18][19] Leukemia or leukaemia(Greek leukos λευκός, “white”; aima αίμα, “blood”) (see spelling differences) is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells (leukocytes). ...

Testing and mitigation

ASTM E-2121 is a standard for reducing radon in homes as far as practicable below 4 picocuries per liter (pCi/L) in indoor air.^[20][21] ASTM International (ASTM) is an international standards developing organization that develops and publishes voluntary technical standards for a wide range of materials, products, systems, and services. ...

Radon test kits are commercially available. The kit includes a collector that the user hangs in the lowest livable floor of the house for 2 to 7 days. The user then sends the collector to a laboratory for analysis. The National Environmental Health Association provides a list of radon measurement professionals.^[22] Long term kits, taking collections for up to one year, are also available. An open land test kit can test radon emissions from the land before construction begins. The EPA and the National Environmental Health Association have identified 15 types of radon testing.^[23] A Lucas cell is one type of device. There are very few or no other articles that link to this one. ...

Radon levels fluctuate naturally. An initial test might not be an accurate assessment of your home's average radon level. Transient weather can affect short term measurements.^[24] Therefore, a high result (over 4 pc/l) justifies repeating the test before undertaking more expensive abatement projects. Measurements between 4 and 10 pc/l warrant a long term radon test. Measurements over 10 pc/l warrant only another short term test so that abatement measures are not unduly delayed. Purchasers of real estate are advised to delay or decline a purchase if the seller has not successfully abated radon to 4 pc/l or less.

The National Environmental Health Association administers a voluntary National Radon Proficiency Program for radon professionals consisting of individuals and companies wanting to take training courses and examinations to demonstrate their competency.^[25] A list of mitigation service providers is available.^[26] Indoor radon can be mitigated by sealing basement foundations, water drainage, or by sub-slab de-pressurization. In severe cases, mitigation can use air pipes and fans to exhaust sub-slab air to the outside. Indoor ventilation systems are more effective, but exterior ventilation can be cost-effective in some cases. Modern construction that conserves energy by making homes air tight exacerbates the risks of radon exposure if radon is present in the home. Older homes with more porous construction are more likely to vent radon naturally. Ventilation systems can be combined with a heat exchanger to recover energy in the process of exchanging air with the outside. Homes built on a crawl space can benefit from a radon collector installed under a radon barrier (a sheet of plastic that covers the crawl space).

Notes

A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... sex Canada (French: Santé Canada) is the department of the government of Canada with responsibility for national public health. ... EPA redirects here. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 145th day of the year (146th in leap years) in the Gregorian calendar. ... EPA redirects here. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 229th day of the year (230th in leap years) in the Gregorian calendar. ... The National Cancer Institute (NCI) is part of the United States Federal governments National Institutes of Health. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 229th day of the year (230th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 229th day of the year (230th in leap years) in the Gregorian calendar. ... EPA redirects here. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 229th day of the year (230th in leap years) in the Gregorian calendar. ... R. William Field is an American Academic Associate Professor in the Department of Occupational and Environmental Health and Department of Epidemiology at the University of Iowa. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 229th day of the year (230th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

External links

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• Iowa Radon Lung Cancer Study
• Los Alamos National Laboratory - Radon
• USGS Periodic Table - Radon
• EPA Iowa Radon Study
• World Health Organization International Radon Project
• Radon Occurrence and Health Risks
• WebElements.com - Radon
• U.S. Environmental Protection Agency — Indoor Air Radon
• Agency for Toxic Substances and Disease Registry — Radon Toxicity Case Study
• (U.S.) National Safety Council information
• U.K. Health Protection Agency information
• Ask TreeHugger: What Do Radon Tests Mean?