20.500.12556/RUL-135018 Analysis of ventilation efficiency as simultaneous control of radon and carbon dioxide levels in indoor air applying transient modelling The impact of ventilation efficiency on radon ($^{222}$Rn) and carbon dioxide (CO$_2$) concentrations in the indoor air of a residential building was studied by applying transient data analysis within the CONTAM 3.4 program. Continuous measurements of $^{222}$Rn and CO$_2$ concentrations, together with basic meteorological parameters, were carried out in an apartment (floor area about 27 m$^2$) located in Ljubljana, Slovenia. Throughout the experiment (October 3–15), frequent ventilation (several times per day), poor ventilation (once to twice per day) and no ventilation scenarios were applied, and the exact ventilation and occupancy schedule were recorded. Based on the measurements, a transient simulation of $^{222}$Rn and CO$_2$ concentrations was performed for six sets of scenarios, where the design ventilation rate (DVR) varied based on the ventilation requirements and recommendations. On the days of frequent ventilation, a moderate correlation between the measured and simulated concentrations (r = 0.62 for $^{222}$Rn, r = 0.55 for CO$_2$) was found. The results of the simulation indicated the following optimal DVRs: (i) 36.6 m$^3$ h$^{−1}$ (0.5 air changes per hour, ACH) to ensure a CO$_2$ concentration below 1000 ppm and a $^{222}$Rn concentration below 100 Bq m$^{−3}$; and (ii) 46.9 m$^3$ h$^{−1}$ (0.7 ACH) to ensure a CO$_2$ concentration below 800 ppm. These levels are the most compatible with the 5C_Cat I (category I of indoor environmental quality, defined by EN 16798-1:2019) scenario, which resulted in concentrations of 656 ± 121 ppm for CO$_2$ and 57 ± 13 Bq m$^{−3}$ for $^{222}$Rn. The approach presented is applicable to various types of residential buildings with high overcrowding rates, where a sufficient amount of air volume to achieve category I indoor environmental quality has to be provided. Lower CO$_2$ and $^{222}$Rn concentrations indoors minimise health risk, which is especially important for protecting sensitive and fragile occupants. ventilation residential buildings transient modelling radon carbon dioxide prezračevanje stanovanjske stavbe nestacionarno modeliranje radon ogljikov dioksid true false true Angleški jezik Slovenski jezik Članek v reviji 2022-02-17 11:54:18 2022-02-17 11:54:20 2022-09-14 04:11:12 0000-00-00 00:00:00 2022 0 0 20 str. iss. 4, art. 2125 Vol. 19 Feb. 2022 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 502/504:697.97 1660-4601 10.3390/ijerph19042125 97826563 RAZ_Dovjak_Mateja_2022.pdf RAZ_Dovjak_Mateja_2022.pdf 1 FF3F7B47AEBA970BAFECBD90A97789FF cc9109e63dfe93ebd32998468a6f8b32109b8c30751ae2e34825732d2d887d51 08469042-8fe0-11ec-abdb-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=153837 https://www.mdpi.com/1660-4601/19/4/2125 0 b721482a-8fdf-11ec-abdb-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=153836 Fakulteta za gradbeništvo in geodezijo 0 0 0