Radon “action level

U.S. EPA estimates that one in every 15 homes nationwide has a high radon level at or above the recommended radon action level of 4pCi/L per liter of air. Radon is the second leading cause of lung... 

The Clinton experience can be contrasted with radon observations in Boyertown, Pennsylvania, where buildings with radon concentrations over 500 times the U.S. EPA action level were found adjacent to buildings below the action level.48 Therefore, the presence of elevated-radon buildings in a neighborhood is at best only an indication that the probability of having a radon problem has increased. 

It is noted that the ICRP has assumed a higher conversion coefficient between annual effective dose equivalent and radon concentration (ICRP, 1984) in recommending an action level for remedial measures in homes, i.e. 1 mSv y"1 per 10 Bq m"3 of equilibrium equivalent radon gas concentration (9 mSv per WLM). If this conversion coefficient were applied to our regional survey data, we would estimate, from the distribution parameters given in table 3, that about 15% of the residents of certain areas of Devon and... 

It is to be noted that the conversion factor of 20 mSv effective dose equivalent per 200 Bq m 3 equilibrium equivalent radon concentration, considered by the ICRP (ICRP, 1984) in recommending an Action Level for remedying high indoor radon concentrations, corresponds to a dose rate of about 40 pGy per y per Bq m 3 radon gas concentration. 

Before standards for indoor exposure to radon can be formally established, work is necessary to determine whether remedies are feasible and what is likely to be involved. Meanwhile, the Royal Commission on Environmental Pollution (RCEP) in the UK has considered standards for indoor exposure to radon decay products (RCEP, 1984). For existing dwellings, the RCEP has recommended an action level of 25 mSv in a year and that priority should be given to devising effective remedial measures. An effective dose equivalent of 25 mSv per year is taken to correspond to an average radon concentration of about 900 Bq m 3 or an average radon decay-product concentration of about 120 mWL, with the assumption of an equilibrium factor of 0.5 and an occupancy factor of 0.83. 

If the equilibrium factor is 0.5, then the NCRP recommended action level is equivalent to 8 pCi/1 or twice the current EPA guidline of 4 pCi/1. It is important to note that NCRP has made its recommendation on the decay product not the radon concentration. There is currently some uncertainty as to the precise level at which action should be taken. There is general agreement that remedial action is clearly needed above 20 pCi/1 and at levels of 100 pCi/1 and higher, immediate action is required. 

Id. at 15. For pnrposes of this stndy, EPA considered screening measnrements eqnal to or in excess of the action level of 4 pCi/L to be elevated. However, there has not been any safe level of radon exposnre established. 

The updated citizen s guide published as provided in subsection (a) of this section shall include a description of a series of action levels indicating the health risk associated with different levels of radon exposure. 

The EPA set a concentration of 4 pCi/1 of air inside homes as an action level, the average radon level in homes is normally around 1.25 pCi/1. Although there is US Congress Legislation from 1988 establishing the goal not to exceed 0.2-0.7 pCi/1 in homes, this has not been found to be practical because of radon levels in ambient air indoors. 

Radon gas concentrations are measured in units called Becquerels per cubic metre Bq/m and a level of 200 RqInP (max) is considered as the action level for homes. This value is double for offices, taking into account that more time is usually spent in the home than at work. The usual level of radon observed normally is 1/10th of the action level (20 Bq/m ). In a study done in UK, it was shown that levels of radon vary considerably from location to location with the possibility of reaching values well above the action level suggested (called high radon potential areas ) [55]. 

It has been estimated that nearly 1 in 15 homes in the United States is affected by radon contamination. Levels higher than 4 picocuries per liter of air (4 pCi/L) have been designated the action level by the U.S. Environmental Protection Agency (EPA). Some level of radon could probably be detected in homes in almost every state. 

This EPA action level is important for two reasons. First, levels of radon higher than 4 pCi/L should be reduced because levels above this are judged to lead to unacceptable risks of lung cancer. Second, it is dilScult to lower the level of radon in most contaminated homes below 4 pCi/L. This last point is an acceptance of the fact that radiation exposure will always be with us. 

If the radon radiation level is above 4 pCi/U EPA reguires that some form of remediation action be taken. 

Additionally, some special circumstances with respect to the regulations and monitoring of the doses are also recommended. Among them, for radon ( Rn) in workplaces, the yearly average activity concentration should be less than 1,000 Bq m in air, as an action level The ICRP derived radon conversion coefficient based on epidemiological determinations corresponds to 6 nSv (Bq h... 

To avoid an unacceptably high exposure from radon, many countries have introduced limitations on the radon concentration in dwellings for chronic exposures. Action levels have been designated above which protective actions should be carried out to decrease chronic exposure. In most countries, action levels for dwellings are established between 200 and 600 Bq m for the annual average radon concentration, based on representative measurements and other parameters. 

The average indoor residential radon level in the United States is about 1.3 picocuries per liter (pCi/L), over three times the average outdoor level of -0.4 pCi/L. While there is no safe level of radon, the action level for mitigation set by the EPA is 4 pCi/L. (One curie of radioactivity is equivalent to the quantity of a given nuclide that provides 3.700 x 10 ° disintegrations per second). Radon levels are often evaluated at the time of a house purchase. However, testing can be carried out at any time by a professional or with a self-test kit. 

Working in mines and other workplaces where radon levels exceed a specified action level ... 

A particular house has an ACH of 0.45/hr during the winter heating season. Due to seepage of radon through the basement floor and walls, the wintertime radon concentration averages 3.1 pCi/liter, below EPA s action level of 4 pCi/liter. 

The known health effect associated with exposure to elevated levels of radon above the action or guidance level is an increased risk of developing lung cancer. The guideline levels for radon in existing homes are as follows ... 

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