Background: With growing concern during the COVID-19 pandemic, indoor environmental quality has received significant attention. Radon, a radioactive gas produced from the decay of radium found in soil, rocks, and building materials, can accumulate indoors, posing serious health risks such as lung cancer. University environments, where occupants spend significant time indoors, are particularly susceptible to prolonged radon exposure. Method: This study focused on the estimation of indoor radon concentrations from multiple university buildings in Shanghai. A field investigation was conducted between June 2020 and August 2022. Continuous radon measurements were conducted in the dormitories and classroom buildings. Environmental factors include indoor air temperature and relative humidity. Results: Radon concentrations were influenced by season, floor level, and measurement period, with the highest concentrations recorded during summer and on lower floors due to reduced ventilation. The mean radon concentration in dormitories was 14.8 +/- 9.2 Bq/m3, and in classrooms 12.6 +/- 6.7 Bq/m3, both below national safety limits and lower than those in the pre-pandemic era. Seasonal effect, floor level, and time of measurement were the significant factors for indoor radon concentrations. Conclusion: This study has identified the main factors that affect indoor radon concentration in university campus. The radon concentrations at the lower floor levels remain the highest in the building. The results provide evidence for conducting refined radon monitoring and risk assessment in campus environment, especially during the summer.

Radon is a naturally occurring radioactive gas found in rocks, soil, and building materials. Precisely because of its gaseous nature, it tends to concentrate in indoor environments, resulting in a danger to human health. The effects of radon have been described, documented, and attested by the international scientific community and recognized as the second cause of lung cancer after cigarette smoking and in synergy with it. In December 2013, the Council of the European Union issued Council Directive 2013/59/Euratom, which establishes basic safety standards relating to protection against the dangers deriving from exposure to ionized radiation and managing the health risks associated with radon. In addition, designing buildings against radon risk in synergy with the use of low environmental impact materials is one of the objectives of building sustainability certifications. This work presents how radon creeps into buildings and reports several technologies that are needed to remove and mitigate the risk associated with indoor radon in existing and new buildings.