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HOW THE RADON STUDY WAS DONE

In carrying out the first systematic geographic survey of radon in California, The Times assembled a scientific advisory panel of leading authorities on radon who assisted in developing a protocol for the study and in analyzing the data.

The panel included specialists from the state Department of Health Services and the University of California’s Lawrence Berkeley Laboratory.

Participants in the study were all employees of the Los Angeles Times. Because participants volunteered and were not randomly selected, The Times Poll conducted a random telephone survey of 462 individuals in Southern California to determine any differences between Times participants’ households and all other households.

Using standard statistical techniques, the results from The Times’ sample were then adjusted to permit conclusions to be drawn about radon levels in households throughout the region.

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Participants also completed a questionnaire in an attempt to determine if there were any correlations between elevated radon levels and various housing and soil characteristics.

Alpha-track radon detectors manufactured by Terradex Laboratories of Glenwood, Ill., were mailed to study participants in Los Angeles and Orange counties and in parts of Ventura, Riverside and San Bernardino counties. A total of 436 employee households completed the 12-month radon-measuring program. Ten additional measurements were made in San Diego County but the sample was not large enough to reach significant conclusions for that region. All the detectors were analyzed by Terradex to determine radon levels.

Participants were asked to place the detectors in a first-floor living area or, for those in multistory dwellings, on a floor as near the ground level as possible. Radon is generally believed to be more concentrated near ground level.

In addition, 66 of the participants were randomly selected to place a second detector in their homes to

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determine if radon levels are higher or lower in the winter. Radon levels are believed to be higher in the winter when doors and windows tend to remain closed because of the weather. Those 66 detectors were deployed for three months starting in December, 1987.

The average radon levels in the 66 residences for the winter period--while still low--were 35% higher than the average annual figure. This is a less extreme difference than has been found in Eastern climates.

Participants on the scientific advisory panel from the state Department of Health Services’ Air and Industrial Hygiene Laboratory were Steven Hayward, a research chemist and manager of the Indoor Air Quality Program; environmental epidemiologist Kai-Shen Liu, and statistician Fan-Yen Huang. Participating from the state Health Services Department’s radiological health branch was associate health physicist Gary Butner.

Also participating were Anthony V. Nero Jr., a physicist with Lawrence Berkeley Laboratory and a leading authority on radon, and Barbara Moed, a radiation geologist with Geo-Radon Services in Berkeley, and Richard Oswald, a health physicist with Terradex.


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