Bequerel (Bq) and Bq/m3
Bequerel is the international standard unit for
radioactivity; that is the rate that radioactive materials decay.
One Bq is one decay per second. The US unit
of radioactivity is the Curie(Ci). One Ci is 3.7x 1010 decays per second. Bq/m3
is the international unit for volumetric activity concentration. The relationship between
activity concentrations is that 1 pCi/L = 37 Bq/m3
Dose units: RAD, REM, Gray(Gy), Sievert (Sv)
There are some thorny details that I will omit in this
definition to give you the basic idea: Dose is a measure of energy absorbed in matter. The
basic units are RAD (US) and Gray (international). 1 Gy=100 RAD. Dose Equivalent
includes the energy deposited and the effectiveness of that dose at producing damage in
biological cells. The basic units are REM (US) and Sv (international). 1 Sv=100 REM.
Effective Dose Equivalent includes the sensitivity of the human organ to
the Dose Equivalent. It is a new concept and is only given in units of Sv.
Environmental radiation is energy created by the decay of
naturally-occurring radioactive elements like uranium, thorium, and potassium.
These elements are found in the soil, air, water, building materials, and food.
Mitigation is the process of reducing radon gas related
exposure in the home or workplace. It usually involves a change in the building's
structure or systems. Often it requires a new device or system to achieve the desired
level of reduction. Common mitigation techniques include increasing indoor
ventilation (open windows, air-to-air heat exchangers), removing radon progeny from the
air (filters, fans), or ventilating the soil surrounding the building.
picoCurie and pCi/L
The US unit of radioactivity is the Curie(Ci). One Ci is 3.7x
1010 decays per second. One picoCurie is 3.7x 10-2decays per second
or 3.7x 10-2Bq. pCi/L is the US unit for volumetric activity
concentration. The relationship between activity concentrations is that 1 pCi/L = 37 Bq/m3
Radiation dose is the
effective energy absorbed by human tissue when struck by radiation. The risk of
developing a cancer is proportional to dose, at least for doses above a “yet to
be determined” threshold. Top
Radiation risks are an increased chance of
developing a cancer when exposed to high doses of environmental or anthropogenic
A nickname for the isotope 222Rn of the element
Radon. 222Rn has a 3.8 day half-life, the longest of any Radon isotope. It is a
noble gas generated by the decay of radium found in rocks and derived materials. It decays
via alpha and beta emission through a series of short-lived progeny, 218Po,214Pb,214Bi,
214Po to a moderately long-lived (21 years) isotope of lead; 210Pb. 210Po
is radon's last mortal daughter. She decays into 206Pb.
The series of nuclei that are produced when radon decays
Nucleus: 222Rn > 218Po>214Pb>214Bi>
214Po> 210Pb>210Bi> 210Po > 206Pb
4d 3 min 27 min 20 min
<1ms 21y 5d
Retrospective means looking to the past. Radon leaves a
residue in glass surfaces that can be used to estimate the average radon
concentration over past decades. Top
A nickname for the isotope 220Rn of the
element Radon. 220Rn has a 55 second half-life, much shorter than 222Rn.
It is a noble gas generated by the decay of radium found in rocks and derived materials.
It decays via alpha and beta emission through a series of short-lived progeny. It is not
as common as radon in the environment. Indoors it is thought to contribute about 10% of
the total airborne radiation dose.
More to come....let me know if there are terms you would like to see
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Last revised :
15 July, 2004
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