Radon’s radioactive decay is the main natural source of small air ions near the ground. Its exhalation from soil is affected by meteorological factors, while aerosol pollution reduces air ion concentrations through ion-particle attachment. This study aimed to analyze correlations between radon, ions, and air pollution under varying conditions and to assess potential health impacts. Measurements were taken at two sites: in early autumn at a suburban part of Belgrade with relatively clean air, and in late autumn in central Belgrade under polluted conditions, with low temperatures and high humidity. Parameters measured included radon, small air ions, particle size distribution, PM mass concentration, temperature, humidity, and pressure. Results showed lower radon concentrations in late autumn due to high soil moisture and absence of nocturnal inversions. Radon and air ion concentrations exhibited a strong positive correlation for both polarities under suburban conditions, whereas measurements in the urban setting revealed a weak negative correlation, despite radon concentrations in soil gas being approximately equal at both sites. Small ion levels were also reduced, mainly due to suppressed radon exhalation and increased aerosol concentrations, especially ultrafine particles. A strong negative correlation (r < −0.5) was found between small air ion concentrations and particle number concentrations in the 20–300 nm range, while larger particles (300–1000 nm and >1 µm) showed weak or no correlation due to their lower and more stable concentrations. In contrast, early autumn measurements showed a diurnal cycle of radon, characterized by nighttime maxima and daytime minima, unlike the consistently low values observed in late autumn.

The application of energy-saving policies in buildings could lead to a decrease in the air exchange rate in dwellings, which could consequently lead to an increase in indoor radon concentration and, therefore, to an increase in resident exposure to ionizing radiation. The aim of the research presented in this paper is to investigate radiological exposure to residents due to the usage of different granites commonly used in Serbia as a building material. From the total of 10 analysed granite samples, a wide range of radon and thoron exhalation rates were found: from <161 μBq m⁻² s⁻¹ to 5220 ± 200 μBq m⁻² s⁻¹ and from <7 mBq m⁻² s⁻¹ to 5140 ± 320 mBq m⁻² s⁻¹, respectively. Assuming a low air exchange rate of 0.2 h⁻¹, the contribution of the measured granite material to the indoor radon concentration could go up to 150 Bq m⁻³. The estimated annual effective doses due to exposure to radon and thoron exhalation from the granite samples were (0.05–3.79) mSv and (<0.01–1.74) mSv, respectively. The specific activity of radionuclides ranged from 6.6 ± 0.5 Bq kg⁻¹ to 131.8 ± 9.4 Bq kg⁻¹ for ²²⁶Ra, from 0.5 ± 0.1 Bq kg⁻¹ to 120.8 ± 6.5 Bq kg⁻¹ for ²³²Th, and from 0.22 ± 0.01 Bq kg⁻¹ to 1321 ± 86 Bq kg⁻¹ for ⁴⁰K. The obtained external hazard index ranged from 0.03 to 1.48, with three samples above or very close to the accepted safety limit of 1. In particular, dwellings with a low air exchange rate (causing elevated radon) could lead to an elevated risk of radiation exposure.

An investigation of the effect of gamma radiation was carried out on the setting time of alkali-activated binder paste. Mechanically activated coal fly ash (FA), ground granulated blast furnace slag (BFS), and their 1:1 mass mixture (MIX) were activated by water glass with a module of 1.5. Fresh paste was cast into molds and exposed to Co-60 gamma radiation, at a dose rate of 9.62–9.53 Gy/h, until the final setting. The initial and final setting times were determined by measuring the penetration of the Vicat needle at regular intervals. The initial setting times were 1 h 3 min for BFS, 1 h 55 min for MIX, and 3 h 28 min for FA. The final setting times were 1 h 10 min for BFS, 2 h 13 min for MIX, and 4 h 1 min for FA. The received doses were 8.02 Gy for BFS, 17.54 Gy for MIX, and 34.14 Gy for FA. Exposure to gamma radiation resulted in a shorter initial setting time for BFS, a shorter final setting time for FA, and results with an insufficiently visible impact on MIX. For dose rates in the 9–10 Gy/h range, the irradiation by Co-60 gamma rays during setting did not lead to flash, nor did it delay the setting of alkali-activated binder pastes.

Ispitivanje intenziteta el. polјa u frekvencijskom opsegu od 27MHz do 6GHz je važno radi procene nivoa izloženosti ljudi elektromagnetnom(EM) zračenju, koje može da utiče na zdravlјe. Ispitivanja su izvršena u zoni gde je potencijalna izloženost nivoima EM polјa najveća. Ispitivane su karakteristične pozicije: viši spratovi i mesta gde je povećana frekventnost lјudi ali i neposredan dvorišni i okolni prostor do najbližeg autobuskog stajališta. Ispitivanje je izvršeno u skladu sa rasporedom postavlјene opreme predmetnog izvora ispitivanja, potencijalnih relevantnih izvora i potencijalnih uzroka perturbacije prema standardnoj akreditovanoj metodologiji ispitivanja EM polјa radio telekomunikacione opreme i sistema. Merna sonda postavlјena je u planiranoj geometriji u datom prostoru na distanci od 1,7m. Tokom merenja, osobe koje čine merni tim, udalјene su od merne sonde bar na distanci od 1,5m. Ovaj pristup osigurava pouzdanost i tačnost merenja bez nepotrebnih rizika po zdravlјe. Na predmetnoj lokaciji instalirana je četvorosektorska bazna stanica koja podržava mobilne tehnologije: GSM 900, LTE 800, LTE 1800 i LTE 2100. Na osnovu izvršenih merenja i proračuna se pokazalo da su intenziteti električnog polјa za LTE 800, LTE 1800 i UMTS sisteme manji od 15,5V/m, 23,4V/m i 24,4V/m, što su referentni granični nivoi za ove sisteme. Vrednosti faktora izloženosti u razmatranom slučaju manje su od 1 u svim zonama, što ukazuje na nizak nivo izloženosti u odnosu na dozvolјene granice.