AARST_Radon_Reporter_Q32022_FINAL

12 | January 2023 RESEARCH Ventilation type Measured multi-family houses Only values above 5.4 pCi/L (200 Bq/m 3 ) on floors above the ground floor Only values above 5.4 pCi/L (200 Bq/m 3 ) on the ground floor All 326 17 % 64 % Natural ventilation 81 25 % 50 % Mechanical exhaust 192 12 % 67 % Balanced ventilation with heat recovery 37 16 % 68 % Building year period Measured multi-family houses Only values above 5.4 pCi/L (200 Bq/m 3 ) on higher floors Only values above 5.4 pCi/L (200 Bq/m 3 ) on ground floors All 326 17 % 64 % -1959 108 27 % 44 % 1960-1979 58 10 % 67 % 1980-1999 84 11 % 77 % 2000-2022 67 13 % 79 % TABLE (7) RADON LEVELS ABOVE THE REFERENCE LEVELS ONLY ON HIGHER FLOORS IN SWEDISH MULTI-FAMILY HOUSES WITHOUT “BLUE CONCRETE” BUILDING MATERIAL RELATED TO VENTILATION TYPE TABLE (8) RADON LEVELS ABOVE THE REFERENCE LEVELS ONLY ON HIGHER FLOORS IN SWEDISH MULTI-FAMILY HOUSES WITHOUT “BLUE CONCRETE” BUILDING MATERIAL RELATED TO BUILDING YEAR PERIOD. Discussion Since the Swedish measurement protocol requires measurements of radon in all apartments on the ground floor with slab on grade foundation type but not for basements, measurement data where 5 or more measured apartments on the ground floor were separately analyzed for buildings with basement. This selection decreased the number of buildings with values above 5.4 pCi/L, only on higher floors, from 20% to 16%. For buildings with slab on grade foundation, the corresponding number was 7%. As can be seen in Table 5, data from workplaces show very similar results. Part of the multi-family buildings with basement where radon levels above the reference level only were found on higher floors might be explained with a smaller number of measurements on the ground floor as can be seen in Table 6. However, for buildings with slab on grade, the Swedish measurement protocol requires measurements in all apartments on the ground floor. Conclusion About 15-20% of Swedish multi-family houses, without the radon-emitting building material “Blue Concrete,” with basements and with radon levels above the Swedish reference level of 200 Bq/m 3 (5.4 pCi/L), would not have been found if no measurements were made on floors above the ground floor. For buildings with slab on grade, the corresponding number is 5-10% in the region. Some houses where higher floors have higher radon values than the ground floor have too high values on both ground and higher floors. The total amount of higher floors with higher values than the ground floor was almost 30% for the multi-family houses with a basement and a little more than 10% for houses with slab on grade. Measurements on the higher floors will give a better understanding of the building's radon situation, which could be important when mitigation work is planned. References 1) Strålsäkerhetsmyndigheten (Swedish Radiation Safety Authority), 2013. Mätning av radon i bostäder- metodbeskrivning, 2) ANSI/AARST, 2017. Protocol for Conducting Measurements of Radon and Radon Decay Products in Multifamily Buildings 3) Rönnqvist, T., 2021. Analysis of Radon Levels in Swedish Dwellings and Workplaces, Strålsäkerhetsmyndigheten , https://www.stralsak - erhetsmyndigheten.se/en/publications/reports/radiation-protection/2021/202128/ ,