Background radiation is a measure of the level of ionizing radiation present in the environment at a particular location which is not due to deliberate introduction of radiation sources.
Radon is a chemical element; it has symbol Rn and atomic number 86. It is a radioactive noble gas and is colorless and odorless. Of the three naturally occurring radon isotopes, only 222Rn has a sufficiently long half-life for it to be released from the soil and rock where it is generated. Radon isotopes are the immediate decay products of radium isotopes. The instability of 222Rn, its most stable isotope, makes radon one of the rarest elements. Radon will be present on Earth for several billion more years despite its short half-life, because it is constantly being produced as a step in the decay chains of 238U and 232Th, both of which are abundant radioactive nuclides with half-lives of at least several billion years. The decay of radon produces many other short-lived nuclides, known as "radon daughters", ending at stable isotopes of lead. 222Rn occurs in significant quantities as a step in the normal radioactive decay chain of 238U, also known as the uranium series, which slowly decays into a variety of radioactive nuclides and eventually decays into stable 206Pb. 220Rn occurs in minute quantities as an intermediate step in the decay chain of 232Th, also known as the thorium series, which eventually decays into stable 208Pb.
Radium Hot Springs, informally and commonly called Radium is a village of 1,339 residents in the East Kootenay region of British Columbia. The village is named for the hot springs in the nearby Kootenay National Park. From Banff, Alberta, it is accessible via Highway 93.
Tehran Metro is a rapid transit system serving Tehran, the capital of Iran. It is the largest metro system in the Middle East. The system is owned and operated by Tehran Urban and Suburban Railway. It consists of six operational metro lines, with construction under way on seven lines including northwestern extension of line 4, south extension line 6, northwestern and east extension line 7, east extension line 2 and Line 10, Line 8 and 9.
Radon mitigation is any process used to reduce radon gas concentrations in the breathing zones of occupied buildings, or radon from water supplies. Radon is a significant contributor to environmental radioactivity and indoor air pollution. Exposure to radon can cause serious health problems such as lung cancer.
Krypton-85 (85Kr) is a radioisotope of krypton.
Radium and radon are important contributors to environmental radioactivity. Radon occurs naturally as a result of decay of radioactive elements in soil and it can accumulate in houses built on areas where such decay occurs. Radon is a major cause of cancer; it is estimated to contribute to ~2% of all cancer related deaths in Europe.
The Emam Khomeini Metro Station is the junction of Tehran Metro Line 1 and Line 2. The station was opened on 21 February 2000, it is located in Toopkhaneh Square between Panzdah-e-Khordad Metro Station and Saadi Metro Station in Line 1 and Mellat Metro Station and Hasan Abad Metro Station in Line 2.
Mirdamad Metro Station is a station in Tehran Metro Line 1, located next to Mirdamad Boulevard. It was opened on 19 May 2009. The station has an outdoor parking facility for commuters.
Doctor Shariati Metro Station is a station in Tehran Metro Line 1. It is located in Shariati Street. It is between Mirdamad Metro Station and Gholhak Metro Station. It was opened on 19 May 2009.
Gholhak Metro Station is a station of Tehran Metro Line 1. It is located in Shariati Street in Gholhak neighborhood. The neighboring stations are Shariati and Shahid Sadr. It was opened on 19 May 2009.
Darvazeh Shemiran Metro Station is the junction of Tehran Metro Line 2 and Tehran Metro Line 4. It is located in junction of Baharestan Street and Mazandaran Street and Namjou Street nad Sepah Street. It is between Imam Hossein Metro Station and Baharestan Metro Station in Line 2 and Meydan-e Shohada Metro Station and Darvazeh Dowlat Metro Station in Line 4.
Ferdowsi Metro Station is a station in Tehran Metro Line 4. It is located in Ferdowsi Square the junction of Enghelab Street and Ferdowsi Street. It is between Darvaze Dolat Metro Station and Teatr-e Shahr Metro Station. It has connection to Tehran Bus BRT1.
Tehran (Sadeghiyeh) Metro Station is the junction of Tehran Metro Line 2 and Tehran Metro Line 5. It is located in Sadeghiye neighborhood near Mohammad Ali Jenah Expressway and Tehran-Karaj Freeway. It is the west end of Line 2 and the east end of Line 5. The next station in Line 2 is Tarasht Metro Station and the next station in Line 5 is Eram-e Sabz Metro Station. It also has a big parking lot and is considered as the most crowded Tehran metro station. It is currently the only above ground station on Tehran Metro Line 2.
The health effects of radon are harmful, and include an increased chance of lung cancer. Radon is a radioactive, colorless, odorless, tasteless noble gas, which has been studied by a number of scientific and medical bodies for its effects on health. A naturally-occurring gas formed as a decay product of radium, radon is one of the densest substances that remains a gas under normal conditions, and is considered to be a health hazard due to its radioactivity. Its most stable isotope, radon-222, has a half-life of 3.8 days. Due to its high radioactivity, it has been less well studied by chemists, but a few compounds are known.
Farhangsara Metro Station is the eastern end of Tehran Metro Line 2, in Iran. It was opened in 2010, with Mohammad-Bagher Ghalibaf attending the inauguration. It is located in Jashnvareh Street in Tehranpars neighborhood. The next station is Tehran Pars Metro Station.
Rahahan Metro Station is a metro station in line3 of Tehran metro, located in Rahahan Square. As suggested by the name, it is connected with Tehran Railway Station
Working level (WL) is a historical unit of concentration of radioactive decay products of radon, applied to uranium mining environment. One working level refers to the concentration of short-lived decay products of radon in equilibrium with 3,700 Bq/m3 (100 pCi/L) in air. These decay products would emit 1.3 × 105 MeV in complete decay. The Nuclear Regulatory Commission uses this definition.
Hossein Abad Metro Station is a metro train station in line 3 of the Tehran Metro. It is located on Mozhdeh Street at Hossein Abad neighbourhood in Northwestern Tehran.
Tetra Cave Natural Monument is a karst cave 1.6 km northwest of Tskaltubo in Tskaltubo Municipality in Imereti region of Georgia. Locally known as White Cave it is located 140 meters above sea level.
Chubtarash Street- 
