brochures, and do-it-yourself guides. Three factors were important to influencing the number of households that mitigated radon: educating the public about mitigation and ensuring availability of qualified contractors, a radon-awareness campaign, and promoting the widespread testing of residential radon levels.
Several studies have described the problems of communicating risk to the general public; a broad review of radon-related risk communication was done by the EPA's Science Advisory Board (1995). A telephone survey was used to assess information about homeowners with indoor air concentrations greater than 740 Bq m-3 (Field and others 1993). Of these homeowners, only 19% identified lung cancer as a possible health outcome of high radon exposure, and fewer than one-third remembered the value measured in their home to within 370 Bq m-3, even within the first 3 months after receiving their test results. In another study 99 homeowners were randomly selected in a community. In this group, 64% expressed concern about radon but only 7% tested their homes (Kennedy and others 1991). These findings tend to show that knowledge about the hazard does not necessarily lead to actions to reduce the risk. A survey of 275 adults showed that 92% had heard of radon and believed it to be a health risk though only 4% believed that they were exposed to high levels of radon gas (Mainous and Hagen 1993). The phenomenon of believing that exposure happens only to others appears common. In this study, younger and less-educated people were more likely to perceive radon as presenting a health risk and women were found to be 3.5 times as likely as men to perceive radon as a risk. Finally, Sandman (1993) showed that among 3,329 homeowners, the likelihood of radon testing was predicted by the degree of general knowledge about radon and a decision to test was related to each individual's perception of the seriousness of the risk.
Three states have detailed results of testing and mitigation programs. New Jersey examined the short-term home radon-test results, including real-estate tests, by month from 1991 to 1997 (J. Lipoti, State Radiation Protection Program of NJ, private communication). Non-real-estate tests make up about 25% of all the tests for radon in houses. When high radon was found in a test, especially airborne concentrations in excess of 3,700 Bq m-3, free radon packets were sent to homeowners within a I mile radius. Roughly one fourth of the homes that received packets used them. These tests were done from January 1996 through April 1997. Another investigation was of the fraction of homes testing high for radon that were not mediated by state-certified contractors. These homes were not reported to have been mitigated. For houses found to have indoor radon concentrations greater than 150 Bq m-3, the percent of dwellings not mitigated ranged from 64 to 72% during the period 1992–1996.
New York state tested radon awareness, testing, and remediation with a survey (NYDH 1997b). The survey included information about ethnic background, age, education, and income and involved more than 1,000 interviews. Of 993 respondents, 152 had tested for radon and 12 had radon concentrations in excess of 150 Bq m-3. Of those in the high-radon group, nine undertook mitiga-