Radon problem

The key point to remember, in the merits of year-round radon removal, is that there is no guarantee that radon problems will not be present even in the summer months. The radon levels found in individual houses are a complex result of radon source strength, soil transport, the number, size, and location of entry points, weather, and the way the house is operated.2 To be certain of maintaining low radon levels in the house normally requires that an SSD mitigation system works properly 24 h per day, 365 days per year. It is for this reason that durability and system performance are very important considerations. The performance level goal for the system is 100% on-time operation for the life of the building. This requires excellent durability of system components and a reliable means for determining whether the system is fully operational at all times. 

The first problems on the list are not specific to radon control but are encountered on nearly every construction job. In spite of quality control and communication problems and the understandable wariness builders show when asked to build something in a different way, the residential construction industry has responded to new techniques, materials, and public demands. The average house being built today is very different from a home built 20 years ago. If a product or a method can be demonstrated to reliably keep radon out without presenting significant problems with cost, scheduling, or installation, many builders would learn to use it. The major difficulty faced by mechanical barrier approaches is the thoroughness that seems to be required to ensure that no radon problem will occur. 

The French drain (also called a channel drain or floating slab) is a construction feature that appears to provoke strong reaction from its defenders and detractors alike. French drains are only a concern in basement foundations. This slab detail is a standard feature in new houses in parts of the country as varied as New York and Colorado, but in other places it is virtually unknown. French drains are used in areas with expansive soils, such as parts of Colorado, to protect the slab from damage if the wall moves. In central New York State, the main function of the French drain is to drain away water that may seep down the walls. One national builder has discontinued and now prohibits the use of French drains in houses because of the potential for radon problems. This builder states that French drains also have been found to significantly increase indoor moisture levels. 

When siting new residential construction, builders would like to determine the potential for radon problems associated with each building site. Unfortunately, at present there are no reliable, easily... 

In an effort to evaluate the risk of an indoor radon problem occurring in a home built on a particular site, researchers have made many types of measurements. The measurements commonly made include9... 

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. 

Between 2% and 5% of the radon problems found in the United States can be attributed to radon in water.50 The most significant radon-in-water problems observed so far in the United States have occurred in the New England states. Houses with individual or community wells seem to have the greatest potential for a problem since the water in those systems is usually not well aerated. 

Radon dissolves into groundwater from rocks or soils. When the water is exposed to the atmosphere, some of the dissolved radon is released. As a rule of thumb, there is an increase of about 1 pCi/L in the air inside a house for every 10,000 pCi/L of radon in the household water.50 Higher radon levels have been observed in individual rooms when water is heated or agitated, such as during shower use.51 Builders should be aware that houses require groundwater as the house water supply could have a radon problem. The only way to be certain that the groundwater is not a potential radon source is to have the water from the well tested. Some states and private companies provide test kits for this purpose. It should also be noted that radon concentrations in water, like radon concentrations in the air, can vary significantly. 

If a well has not been drilled, a nearby well may be an indicator of potential radon problems. Identifying potential radon-in-water problems by using the results from adjacent wells is subject to the same problems that were mentioned earlier. There is no guarantee that the neighbor s well is producing water with the same characteristics as the new well will produce since it may not be from the same stratum. The limited data available on houses with radon-in-water problems indicate that adjacent houses with similar wells sometimes produce similar radon-in-water problems and sometimes do not. However, few isolated radon-in-water problem houses have been observed. 

Osborne, M.C., Resolving the radon problem in Clinton, NJ, houses, in Indoor Air 87 Proceedings of the 4th International Conference on Indoor Air Quality and Climate, Vol. 2, Berlin, Germany, pp. 305-309, August 1987. 

This volume contains the reports presented at a symposium held as part of the 191th National Meeting of the American Chemical Society. The chapters present recent findings on a number of aspects of the indoor radon problem. In this introductory chapter, an overview of these reports is presented that highlights some of these results and suggests areas where uncertainties still remain. 

It is clear that some proper planning in the design phase of new houses can lead to less likelihood of indoor radon problems and make provision for lower cost modifications later to mitigate against such problems. The experience in Sweden is that houses with low radon concentrations can be constructed on high risk soils by proper design and construction practices. 

This volume represents a collection of papers that provide a considerable amount of recent results and reflect the current level of scientific understanding of radon related problems. However, with the increased public interest and the resulting increased scientific study, it can be expected that there will be many important new findings and our knowledge of the nature and extent of the indoor radon problem will be greatly expanded in the next few years. 

Snihs,J.O., The Approach to Radon Problems in Non-Uranium Mines in Sweden, in Proc. Third Int. Congr. Prot. Assoc, p 909 (IRPA), U.S.A.E.C. Conf. 73097-P.2. (1973). 

HOPKE Indoor Radon Problem Explained for the Layman... 

Hopke P. 1987. The indoor radon problem explained for the layman. In Hopke P, ed. Radon and its decay products. Washington, DC American Chemical Society, 572-586. 

Snihs J. 1974. The approach to radon problems in non-uranium mines in Sweden. In Snyder W, ed. Proceedings 3rd International Congress on International Radiation Protection Association. U.S. Atomic Energy Commission. CONF-730907-P2, 900-911. 

W.J. Angell. The U.S. Radon Problem, Policy, Program and Industry Achievements, Challenges and Strategies, Radiation Protection Dosimetry 1-6 (2008). 

Other short-lived isotopes can, however, still be detected in nature. The element number 86, radon (Rn), has several isotopes, the most long-lived of which has a half-life of only 3.8 days. How is it then possible that we have radon problems in our mines and our houses The answer is that radon certainly disintegrates rapidly but is also being formed continuously. Radon is part of the radioactive uranium decay series ... 

In order to find the stable refracted 3D seismic problem (in a layer), which reduces to a sequence of 2D Radon problems with weight, we need to use a completely different foliation with nonlinear slides. In the case Vq = m + hz, we encounter spherical slices, as we will see in the next section. 

After travel times are measured we use an inversion formula (21) that reduces our problem to the planar 2D Radon problems in discs. Then we use algorithms from [3] for inverting it. 

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