Testing was not performed in the schools. Instead, the study uses state data for residential homes between 1999 and 2022 that are in the same ZIP codes as schools examined by the study. Yang and his coauthors then averaged the radon readings across the ZIP codes to estimate how many picocuries per liter students and faculty might be exposed to on an average day for Allentown, Bethlehem Area, Northampton Area, Southern Lehigh and Northwestern Lehigh school districts. The study says that the meaningful radon exposure differences between households and schools are minimal.
All the study ' s estimates were above the EPA ' s action level. The highest estimated levels were in Northwestern Lehigh, at 18.7 to 20.1 picocuries per liter. Northampton and Southern Lehigh were not too far behind, with estimates ranging from 11.2 to 19.3 picocuries per liter and 7 to 20.1 picocuries per liter, respectively. Allentown and Bethlehem were the lowest, with most of their schools estimated to have levels between 5 and 7 picocuries per liter ‐ still above the EPA action level.
According to the study, 7,651 children ‐ 44 % at the elementary level ‐ attend public schools where radon levels were estimated to be nearly three times greater than the EPA action level. The study also estimates that some children may have been exposed to more than double the amount of radon‐based radiation than the average American.
" If you were going to the doctor and they were going to expose you to that much radiation, they would probably give you a significant warning of what you ' re being exposed to," Yang said. For a lot of students, especially someone who could be potentially very young, they could be affected more by radiation, Yang said.
How districts are responding
Representatives from two of the five districts examined by the study told The Morning Call that they test for radon regularly, and leaders from two others said they plan to test in the near future. All said they have taken the study and inquiries from the public about radon seriously.
Jennifer Holman, superintendent of Northwestern Lehigh, said the district performs radon sampling in school buildings every three years. They did it most recently in June 2022 and all classrooms measured fell below the Pennsylvania DEP and EPA action level of 4 picocuries per liter.
Melissa Reese, spokesperson for Allentown School District, said in an emailed statement that the district performs radon testing in its schools every two years, ensuring that all facilities meet or exceed state and federal health and safety guidelines.
She said in 2017 the district conducted a comprehensive radon assessment across all schools and the majority tested below the Pennsylvania DEP ' s action level.
" In six schools, isolated areas showed levels near or slightly above the guideline, though licensed environmental professionals confirmed that none of the readings posed an immediate health risk," Reese said.