Radon Individual Dose Calculator

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For educational purposes only. No warranty.
Calculation is an assumption only.

Calculate the radiation dose rate, dose, and estimated health risk for an individual exposed to a known concentration of radon and its decay products.

Enter the parameters and click the "Calculate" button below.
"t" means metric ton.

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Radon-222 Input Data
NumberUnitEquilibrium FactorRisk Factor
per WLM
(working level month)1 WL exposure for 170 hours
Bq/m3 EEC
pCi/l EEC
MBqh/(m3a) EEC
Occupancy and Dose Factor
worktime: h/year for years,
at worker's dose factor of mSv/WLM
indoor occupancy: % of year
for years,
at public's dose factor of mSv/WLM
outdoor occupancy: % of year



This calculator performs radiation dose calculations for individuals exposed to Radon-222 and its decay products.

The calculator only determines doses to exposed individuals.

The calculator only determines dose rates for situations, where the activity concentration or annual exposure of radon and/or its progeny is known.

Parameters shown are reasonable initial values which can be modified as needed.

This is ONLY an ESTIMATE. It does not take into account food you eat which contains radition.

Radioactivity or the strength of radioactive source is measured in units of becquerel (Bq).

1 Bq = 1 event of radiation emission per second.

One becquerel is an extremely small amount of radioactivity. Commonly used multiples of the Bq unit are kBq (kilobecquerel), MBq (megabecquerel), and GBq (gigabecquerel).

1 kBq = 1000 Bq, 1 MBq = 1000 kBq, 1 GBq = 1000 MBq.

An old and still popular unit of measuring radioactivity is the curie (Ci).

1 Ci = 37 GBq = 37000 MBq.

One curie is a large amount of radioactivity. Commonly used subunits are mCi (millicurie), µCi (microcurie), nCi (nanocurie), and pCi (picocurie).

1 Ci = 1000 mCi; 1 mCi = 1000 µCi; 1 µCi = 1000 nCi; 1 nCi = 1000 pCi.

Another useful conversion formula is:

1 Bq = 27 pCi.

Becquerel (Bq) or Curie (Ci) is a measure of the rate (not energy) of radiation emission from a source.

When a radioactive material gets in the body by inhalation or ingestion, the radiation dose constantly accumulates in an organ or a tissue. The total dose accumulated during the 50 years following the intake is called the committed dose. The quantity of committed dose depends on the amount of ingested radioactive material and the time it stays inside the body.

What are "working level" and "working level month"?

In underground uranium mines, as well in some other mines, radiation exposure occurs mainly due to airborne radon gas and its solid short-lived decay products, called radon daughters or radon progeny. Radon daughters enter the body with the inhaled air. The alpha particle dose to the lungs depends on the concentration of radon gas and radon daughters in the air.

The concentration of radon gas is measured in units of picocuries per litre (pCi/L) or becquerels per cubic metre (Bq/m3) of ambient air. The concentration of radon daughters is measured in working level (WL) units this is a measure of the concentration of potential alpha particles per litre of air.

The worker's exposure to radon daughters is expressed in units of Working Level Months (WLM). One WLM is equivalent to 1 WL exposure for 170 hours.

1 WL = 130,000 MeV alpha energy per litre air

          = 20.8 µJ (microjoules) alpha energy per cubic meter (m3) air

WLM = Working Level Month

         = 1 WL exposure for 170 hours

Often people use the concentration of radon gas (pCi/L) in the air to estimate the WL level of radon daughters. Such estimates are subject to error because the ratio of radon to its decay products (radon daughters) is not constant. (This is where the "Radon Busters" trick you.)

Ask your local radon busters about the ratio of radon gas to its decay products. Ask if the ratio is constant. It is not and this means the EPA and anyone who sells or tests using the (pCi/L) formula is selling you a SCAM ONLY. You would have got more for your money buying a 2lb bag of brazil nuts!!

Equilibrium factor is ratio of the activity of all the short-lived radon daughters to the activity of the parent radon gas. Equilibrium factor is 1 when both are equal. Radon daughter activities are usually less than the radon activity and hence the equilibrium factor is usually less than 1.


The radon business is a scam

Radon Busters

Foods that have above-average levels of radiation are potatoes, bananas, kidney beans, nuts , and sunflower seeds. Among the most naturally radioactive food known are brazil nuts, with activity levels that can exceed 12,000 picocuries per kg. There are approximately 120 nuts in a kilogram or 2.2 lbs. Bananas cause radiation exposure even when not ingested; for instance, standing next to a crate of bananas causes a measurable dose. The average radiologic profile of bananas is 3520 picocuries per kg, or roughly 520 picocuries per 150g banana.

(So eating 2 bannas  is about 1040 picocuries. So about 8 (a bunch) is like eating a 2.2 lbs of brazil nuts.) Estimated.

It has been suggested that since the body homeostatically regulates the amount of potassium it contains, bananas do not cause a higher dose. However, the body takes time to remove excess potassium, time during which a dose is accumulating. In fact, the biological half-life of potassium is longer than it is for tritium, a radioactive material sometimes leaked or intentionally vented in small quantities by nuclear plants. Also, bananas cause radiation exposure even when not ingested; for instance, standing next to a crate of bananas causes a measurable dose. Finally, the banana equivalent dose concept is about the prevalence of radiation sources in our food and environment, not about bananas specifically. Some foods (brazil nuts for example) are radioactive because of radium or other isotopes that the body does not keep under homeostatic regulation.

The radon business is a scam (Find out why here.)



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