Development and distribution of radon risk maps in New York State

Radon maps for each county in New York State have been developed onthe township level indicating the percent of homes with .148 Bq/m 3 (4 pCi/l)in the indoor air of the basement and living area. Estimates are based ona combination of nearly 45,000 basement-screening measurements and correlationsto surficial geology. Many of the towns and cities in the State with the highestaverage indoor radon concentrations are located on highly-permeable gravellysoils formed during the retreat of the Wisconsinan Glaciation. As many towns(32% of total) had .5 measurements, a project to obtain additional measurementsin high-risk towns produced results comparable to estimates based on correlationsto surficial geology. Radon risk maps for each county have been distributedto municipal governments, schools, and professionals in activities relatedto homes, buildings, and indoor air quality.