eng Science and Education Publishing Applied Ecology and Environmental Sciences 2328-3920 2021-06-03 9 6 580 584 10.12691/aees-9-6-1 AEES2021961 article B. Kharkamni 1 D.D. Wahlang donn.weg@gmail.com 1 Department of Physics, Lady Keane College, Shillong, Meghalaya, India, 793001 Measurement of indoor radon gas and its progeny was carried out in the rooms and laboratories of Lady Keane College, Shillong, using LR-115 films, Type II, which is a Solid State Nuclear Track Detector (SSNTD). The radon concentration in the different rooms varies from 27.88 Bqm-3 to 61.01 Bqm-3, with an average of 42.02 Bqm-3. The results obtained were well within the prescribed safety limit of 100 Bqm-3 as laid down by the World Health Organization. The average indoor radon concentration was slightly higher than the world average of 40 Bqm-3. The Potential Alpha Energy Concentration (PAEC) recorded a maximum of 6.60 mWL and a minimum of 3.01 mWL, with the average being 4.54 mWL. The Annual Effective Dose Equivalent (AEDE) ranges from 0.16 mSv/y to 0.35 mSv/y, which was also well within the prescribed limit of 3mSv/y - 10 mSv/y. The average of the Annual Effective Dose Equivalent was 0.24 mSv/y which was also below the world average of 1.15 mSv/y. http://pubs.sciepub.com/aees/9/6/1/aees-9-6-1.pdf radon progeny indoor LR-115 films dose