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This study presents the results of a spatiotemporal analysis of indoor radon concentration dynamics at the Al-Farabi Kazakh National University (Almaty, Republic of Kazakhstan), located near the Almaty tectonic fault. The research is based on a 2.5-year monitoring campaign of radon levels using the RAMON-02A radiometer. The radon activity concentration ranged from 1.29 ± 0.19 to 149 ± 22 Bq/m3. The distribution of radon concentrations was found to follow a lognormal law, with a skewness coefficient of 1.55 and kurtosis of 4.7. The mean values were 28.7 ± 4.2 Bq/m3 (arithmetic mean) and 24.5 ± 3.6 Bq/m3 (geometric mean). Distinct seasonal and monthly variations were observed: the lowest concentrations were recorded during the summer months (August—20.8 ± 3.1 Bq/m3), while the highest were observed in spring and winter (May—34.0 ± 4.9 Bq/m3, December—34.2 ± 4.9 Bq/m3). The springtime increase in radon levels is attributed to thermobaric effects, limited ventilation, and precipitation, which contributes to soil sealing. Autocorrelation analysis revealed diurnal, seasonal, and annual fluctuations, as well as quasi-periodic variations of approximately 150 days, presumably linked to geophysical processes. Correlation analysis indicated a weak positive relationship between radon concentration and air temperature during winter and spring (≈0.2), and a pronounced negative correlation with atmospheric pressure in winter (−0.57). The influence of humidity was found to be minor and seasonally variable.

Radon is a major source of naturally occurring radioactivity, and its measurement is considered extremely important in radiation protection, given its association with lung cancer. This pilot study aimed to estimate the annual effective dose received by students and staff based on monitoring data on the concentration of radon in the buildings of al-Farabi Kazakh National University (Almaty, Republic of Kazakhstan), based on the distance to the tectonic fault. The measurements were recorded daily from February 2021 to September 2022 using a RAMON-02 radiometer (SOLO LLP, Almaty, Kazakhstan). All measurements were taken from the basement to the top floor under normal conditions of use. The average accumulated concentrations of radon in the studied buildings ranged from 16.34 to 78.33 Bq/m3, which is below the maximum level of 100 Bq/m3 established by the World Health Organization (WHO) and the legislation of the Republic of Kazakhstan (200 Bq/m3). Relatively high values were recorded in the basement of the Faculty of Physics and Technology building (282.0 Bq/m3 in winter, 1742.0 Bq/m3 in spring, 547.7 Bq/m3 in summer, and 550.7 Bq/m3 in autumn), which is located closest to the tectonic fault and poorly ventilated. In almost all rooms (94%), radon levels were within the WHO-recommended reference level. The averaged results show the influence of the distance to the fault on the average indoor radon levels. The annual effective dose of radon for university students and staff ranged from 1.09 mSv/year to 1.53 mSv/year. The excess lifetime risk of developing cancer ranged from 0.44% to 0.61%.

The radon decay product 210Pb is a known component of tobacco. In this study, the activity concentration of 210Pb in the most popular cigarette brands (six samples) for Kazakhstan consumers was determined by beta spectrometry. The activity levels of 210Pb ranged between 2.69 ± 0.27 and 27.42 ± 2.74 mBq per cigarette. Higher activity concentrations for 210Pb were found in Sample No.4 and showed an excess of the world average by 1.8 times. The average activity concentrations of 210Pb in cigarette tobacco were 10.42 ± 1.04 mBq cig−1. The daily activities inhaled in the lungs of a smoker, and the resulting effective doses due to cigarette smoking were calculated. Effective doses per year due to cigarette smoking were calculated assuming that 42.13% of the 210Pb in tobacco were retained in the lungs of the smokers. It is concluded that for a smoker in Kazakhstan, the average effective dose ranges from 9.1 ± 0.9 μSv/year to 92.8 ± 9.3 μSv/year for a cigarette consumption of one pack of cigarettes per day. The results indicate that the annual effective doses from inhalation of 210Pb due to smoking one pack of cigarettes per day are from 7 to 58 times (for different types of cigarettes) greater than the annual effective doses from ingestion of radionuclides via the diet.