Radon measurement

Since radon is a colorless, odorless, and tasteless gas, the only way to detect its presence is to sample and analyze an area s air using a conventional radon measurement test. If the test reveals elevated radon levels, the homeowner will have to decide what steps to take to reduce the levels.7 The higher the level of radon present in a home, the more likely an active radon reduction system such as subslab depressurization (SSD)8 may be required. Lower radon levels may require only a passive reduction system, such as simple sealing. 

Radon measurements in the interstitial soil and bedrock pores. 

It is clear from Table 31.3 that soil radon measurements that varied over an order of magnitude produced significantly less than a factor of 2 difference in the indoor radon levels. Predictions of radon potential based on soil radon measurements would be highly suspect based on these data. 

The major drawback to using the Florida study to support the correlation between indoor and soil measurements was that the indoor measurements were obtained from 3-day closed-house charcoal measurements, and soil radon was obtained from 1-month alpha track measurements buried 1 ft beneath the soil surface. Comparisons of charcoal and alpha track data are generally not recommended since they are quite different measurement techniques, and represent radon levels over different time periods. However, the study was subjected to numerous quality control checks including deployment of alpha track detectors in 10% of the houses to obtain a check on indoor air measurements made by charcoal canisters. In spite of the measurement drawbacks, the study indicates that soil radon measurements taken alone are not a dependable predictor of potential indoor radon concentration. 

Using the permeability and soil radon measurements for the gravel soils in New York State to compare with the Swedish guidelines would result in a recommendation for radon-resistant techniques to be used in a large fraction of new houses in all the areas listed, except Long Island. 

The major difference between these data and the Florida survey data in Table 31.3 is that this portion of the NEWHEP data was collected from newly constructed houses where passive radon-resistant construction features were being tested. There are no data on control houses in the same area that did not have those built-in features, making it difficult to compare soil radon measurements with indoor radon concentrations. It appears, however, that passive-only building techniques do not consistently result in indoor radon levels below 4 pCi/L. 

Aside from the difficulty in correlating soil radon measurements with indoor radon measurements, various field studies have also shown that obtaining a representative soil gas measurement is difficult. Soil gas radon measurements were made with a permeameter in seven central Florida houses.42... 

Indoor Radon and Soil Radon Measurements in Colorado and Michigan... 

Steinhausler (1987) and Martell (1987) review the dosimetric models and related model studies. Their view is that there are still very large uncertainties in the existing data and in the extrapolation from the exposure and response data for underground miners and experimental animals to the health effects of the radon progeny levels to which the general public is exposed. B.L. Cohen (1987) describes his work to relate radon measurements with lung cancer rates for various geographical areas to test the concept of a dose threshold. 

This inverse relationship between equilibrium factor and "unattached" fraction and their relationship to the resulting dose is important in considering how to most efficiently and effectively monitor for exposure. This inverse relationship suggests that it is sufficient to determine the radon concentration. However, it is not clear how precisely this relationship holds and if the dose models are sufficiently accurate to fully support the use of only radon measurements to estimate population exposure and dose. 

Table III shows the average radon in the air when water is used on a typical day. The average is taken from the periods of water use of greater than 5 gallons in 10 minutes. These time intervals begin with the water use and extend to 2 hours after the water use. All radon measurements in the air during this water use time interval are averaged in Column 3. The non-water-use times are averaged in Column 2. Columns 2 and 3 have the average picocuries per liter taken in the 10 minute time intervals. Houses 3016, 3045, 3090,...

Reading Prong in Pennsylvania. The distributions of the radon measurements from the Chester, NJ region and the nearby region centered around Morris County, NJ and that at Syracuse, NY are similar to those measured in Northern Virginia and Maryland and the Wilkes-Barre/Scranton area and are not plotted in Figure 3 to avoid overcrowding. 

George, A. C., and J. Eng, Indoor Radon Measurements in New Jersey, New York and Pennsylvania, Health Phys. 45 397 (1981). 

The objectives of this study are to determine the frequency distribution of radon levels in residential structures on a nationwide basis and to investigate factors which affect these levels. This study is needed to obtain a more accurate estimate of the average radon level in homes and to provide reliable data on the number of homes exceeding various radon levels. Such information will provide a better understanding of the magnitude of the public health problem associated with indoor radon levels. In addition this information will establish the base line level against which results of other surveys and indoor radon measurements can be compared. 

A relatively large number of indoor radon measurements have already been made, particularly during the last 6-12 months. However, most of these measurements are not useful in defining the national frequency distribution of indoor radon levels because there are a number of uncertainties and limitations associated with these measurements. These uncertainties include the different purposes for the measurements, the widely varying sample designs, and the many different sample collection and measurement procedures used. 

Annamaki M., 1978, Radon Measurements in Finnish Dwellings, Nordic Society for Radiation Protection, 5th, Visby. (In Finnish.)... 

Castren 0., Winqvist K., Makelainen 1 and Voutilainen, A., 1984, Radon Measurements in Finnish Houses, Radiation Protection Dosimetry, 7, 33-337. 

In the 1955-56 study the radon measurements were usually taken in the living rooms. The gamma measurements were made in several rooms. All samples were taken before noon. With regard to the ventilation, the houses were divided into two groups one termed "ventilated", where the dwelling had been aired one or two hours before the measurements. The dwellings in the group named "unventilated" had not been aired since the day prior to the measurements. 

Fleischer, R.L. and Turner, L.G., Indoor radon measurements in the New York capital district, Health Phys, 46 5, pp. 999-1011,... 

Figure 4) shows some correlation with,theTindoor radon measurements. 

Castren, 0., K. Winqvist, I. Makelainen and A. Voutilainen, Radon measurements in Finnish houses. Radiation Protection Dosimetry 7 333- 336 (1984). 

M kel inen, I., Calibration of bare LR-115 film for radon measurements in dwellings. Radiation Protection Dosimetry J 195-197 (1984). 

Figure 4. Cumulative frequency distributions of radon concentration for dwellings with different house constructions traditional wooden, ferro-concrete and prefabricated. Numbers, arithmetic means and S.D.s, geometric means, medians, and ranges of radon measurements are also indicated at the bottom of the figure.

We have made the DSC the standard method for the radon measurement. The calibration procedures have been described elsewhere (Shimo et al., 1983) Briefly, the Rn-222 emanating from a standard Ra-226 hydrochloric acid solution (37 kBq) contained in a bubbling bottle entered a large stainless steel container (937 ). 

Negro, V. C. and S. Watnick, "FUNGI A Radon Measuring Instrument with Fast Response, IEEE Trans. Nuclear Science, 25 757-761 (1975). 

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