Radon concentration measurements were performed at Technical College of Applied Sciences in
Zrenjanin during summer, as part of the “Radon level measurements” studies financed by the
Provincial Secretariat for Higher Education and Scientific Research (the project is currently
going on). The two lowest level rooms of the College building were examined, the basement
and the ground floor. Measurements were performed with the active type radon detector based
on alpha spectrometry (brand Airthings) which is capable of both long-term (up to 1 year) and
short-term (a few days) continuous monitoring. The detector measured radon for 48 h in each of
the rooms. The doors and the windows were closed during this period and the rooms were not
ventilated for at least 12 h prior to the procedure. For short term measurements in 12 rooms
radon level ranged from 10 $Bq/m^3$ to 36 $Bq/m^3$ with a mean value of 20 $Bq/m^3$. The results are
compared with the previous results obtained in the same rooms during spring time
measurements campaign. Spring time data were slightly higher and the ratio of the spring over
summer medium radon concentration is 1.31. The maximum measured radon gas concentration at TCAS is below National Reference Level Limits of 400 $Bq/m^3$.