IEA_AARST_Radon_Reporter_JUNE_2024

18 | June 2024 DATA/MAPPING Results of Upper Floor Tests The question often arises: since radon comes from the ground, why does the measurement standard require testing on upper floors, such as in an apartment building or high-rise condos? One reason is that radon gets released from some concrete floors and walls. In one Florida skyscraper, a condo many floors above the ground was found to have elevated radon levels. At one time, concrete manufacturers used radioactive waste material (called phosphogypsum) left behind from Florida’s phosphate mining industry as aggregate for the concrete. Aggregate, which is material such as sand or gravel, makes up approximately 60-75% of concrete. Elevated radon on upper floors is a significant problem in Florida: 24.2% of upper-level radon tests conducted were 4.0 pCi/L or higher. Evidence from the Radon Map Data Sheets can be used by radon professionals in FL to assure their clients of the necessity of upper floor testing, even if the specific project does not require it. The EPA Radon Zone Map vs the Florida Radon Map Project In 1993 the EPA created a map to help identify areas in the U.S. with different levels of radon risk. Based on the results of testing for radon in 5700 homes, geologic factors, and ambient air data, the EPA categorized 3000 plus U.S counties into one of three radon zones based on the predicted indoor radon levels: • Zone 1: High potential; predicted average indoor radon levels greater than 4 pCi/L • Zone 2: Moderate potential; predicted average indoor levels from 2.0 to 3.9 pCi/L • Zone 3: Low potential; predicted average indoor levels less than 2.0 pCi/L. Although EPA has stated that the county data and map are no substitute for testing a home, and that its map should not be used to determine if a home should be tested, home builders, building codes, realtors and others use this information to determine whether to test or to require testing. UPPER FLOOR TEST DATA Total number of upper floor test conducted 34,408 4.0 pCi/L or above 24.2% (8,334) Highest floors with elevated radon. 44th floor – 4.1 pCi/L – Miami Dade County 37th Floor – 6.5 pCi/L Broward County 33rd Floor – 6.0 pCi/L Lee County Highest radon on an upper floor. 72 pCi/L on 3rd Floor – Broward County 68.6 pCi/L on 5th Floor – Leon County 58 pCi/l on 5th floor - Broward County Counties with highest amount of elevated radon on upper floors. County # Elevated Results % Elevated Results Brevard 95 52.5% Palm Beach 1615 41.7% Broward 1765 39.5% Sarasota 77 30.4% Lee 1560 29.7% Orange 330 25.2% Collier 2356 23.9% Miami-Dade 777 12.7%