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Article

Radon Concentration Assessment in Urban Romanian Buildings: A Multistory Analysis

by
Ștefan Florică
1,2,
Alexandru-Iulian Lupulescu
1,*,
Tiberius Dicu
1,*,
Ancuța Cristina Țenter
1,2,
Mircea-Claudiu Moldovan
1,
Gabriel-Cristian Dobrei
1,
Luana Copaci
1 and
Alexandra Cucoș
1
1
“Constantin Cosma” Radon Laboratory—LiRaCC, Faculty of Environmental Science and Engineering, Babes, Bolyai University of Cluj-Napoca, 400294 Cluj-Napoca, Romania
2
S.C. RADON CONTROL S.A., 400294 Cluj-Napoca, Romania
*
Authors to whom correspondence should be addressed.
Atmosphere 2024, 15(11), 1267; https://doi.org/10.3390/atmos15111267
Submission received: 20 September 2024 / Revised: 16 October 2024 / Accepted: 21 October 2024 / Published: 23 October 2024
(This article belongs to the Special Issue Atmospheric Radon Concentration Monitoring and Measurements (2nd Edition))
Browse Figures
Versions Notes

Abstract

:
Radon (Rn 222) is a significant contributor to natural radiation exposure in residential environments such as single-family houses and multistory buildings. This study monitored radon activity concentration (RAC) in 455 apartments in 30 multistory buildings in Buzău, Romania. Integrated measurements of the RAC using CR-39 nuclear track detectors were conducted for a period of 3 to 4 months. The results revealed that the RAC varies between buildings, with an annual average between 33 and 77 Bq/m3. This variation may be attributed to poor ventilation and the chimney effect in common ventilation ducts, which may facilitate radon displacement vertically. Also, apartments with low occupancy or inadequate ventilation showed higher radon levels of up to 285 Bq/m3. The study highlights the potential risk of increased radon exposure in energy-efficient buildings due to poor ventilation, emphasizing the need for special attention to radon mitigation measures in building design. The results emphasize that the RAC is influenced by building characteristics, room use, and ventilation, with significant implications for health risks in urban residential environments.

1. Introduction

Radon (222Rn) is a radioactive gas that originates from the decay of Uranium (238U), which is encapsulated in various mineral forms in all types of rocks. Therefore, radon is found everywhere in the environment, and the amount contained depends on the minerals in the rocks in the area, their emanation coefficient, and the interaction between geology and pedology, since the way the soil forms affects the emanation coefficient directly. However, a series of variables primarily related to construction and architectural details influence the migration and accumulation of radon inside buildings [1]. Radon is widely recognized as the primary cause of natural radiation exposure for humans, making a considerable contribution to the overall radiation dosage, especially in indoor environments where it can accumulate to significant levels [2,3,4,5].
The International Agency for Research on Cancer (IARC) and the World Health Organization (WHO) have classified radon as a human carcinogen, where radon exposure is also recognized as the second most common cause of lung cancer after smoking [4,6]. Studies have shown that non-smokers account for a substantial percentage of lung cancer cases, and the risk of lung cancer increases with both the level and duration of radon exposure [3].
The inherent tendency of individuals to spend significant amounts of their time indoors increases the probability of being exposed to radon. According to the World Health Organization (WHO), most individuals spend considerable amounts, somewhere between 80% and 90% of their time, within enclosed environments such as homes, workplaces, or educational premises [4]. Therefore, this form of exposure becomes more significant, as radon levels exhibit higher concentrations in homes due to the lack of ventilation in comparison to other building types [7,8].
It is acknowledged that single-family homes typically contain higher radon concentrations than multistory buildings [9,10]. This is likely because single-family homes have more direct and extensive ground contact, which may facilitate the easier infiltration of radon indoors [9].
Regarding the variability of radon activity concentrations (RACs) in apartment buildings, lower floors often exhibit higher radon levels compared to upper floors, with the RAC decreasing with increasing height [11,12,13,14,15]. First and foremost, this tendency can be attributed to the proximity of the lower floors to the most significant radon source, namely the soil. Such close contact can result in elevated levels of radon, especially on the bottom floor, as radon infiltrates through cracks and gaps in the foundation and floors [16,17]. Conversely, as we ascend to higher floors, radon levels generally decline due to the growing distance from the ground and the diminishing influence of its impact in relation to elevation [17,18]. Additionally, upper floors generally avail themselves of more effective ventilation, as they are more exposed to stronger air currents [19] that can also facilitate the dispersion of radon. Furthermore, in high-rise buildings, the layers of construction and the materials used for insulation can serve as an extra obstacle to radon, restricting its flow toward the upper floors [20].
However, several studies have reported different situations in which the RAC in multistory buildings increased as the height of the building grew [21]. Phenomena, like the chimney effect, particularly in tall buildings and colder climates, can explain these cases by drawing radon from lower floors to higher ones [17]. Additionally, specific ventilation and air conditioning systems have the potential to transfer air laden with radon, resulting in elevated levels of concentrations on higher levels of the building [22].
In Romania, studies focusing on the RAC in residential environments have primarily targeted single-family homes [1,23,24,25,26], while research on radon levels in apartment buildings has been much less frequent [27,28]. This focus can be explained by the fact that, at the European level, including the indoor radon map developed by the Joint Research Centre (JRC), measurements have specifically concentrated on ground floors, as these are the areas with the highest radon exposure [29,30,31]. Single-family homes have been particularly targeted because they tend to have the highest RAC due to direct contact with the soil [29,32].
According to Eurostat statistics [33], approximately 35% of Romania’s population lives in apartment buildings, predominantly located in urban areas. From 2022 to 2023, there was a slight increase of 2% in the construction of apartments in urban areas, indicating a growing trend towards urbanization and a predilection for apartment living. Romania is currently engaged in vigorous efforts to improve the energy efficiency of its residential buildings, especially multi-family residential structures such as apartment complexes. The initiative is a component of wider European Union policies, including the European Green Deal, and Romania’s obligations under the Energy Performance of Buildings Directive (EPBD) of the EU.
However, scientific evidence suggests that thermal encapsulation or energy-efficient retrofitting of buildings, which includes improving insulation and sealing, can inadvertently increase indoor radon levels because increased airtightness can reduce ventilation, which can trap radon gas inside the building [1,34,35,36]. A study conducted in Romania investigated radon exposure in energy-efficient homes and found a 27% increase in radon levels compared to conventional residences lacking thermal insulation [37].
Given the increasing trend toward urbanization and the construction of new apartment buildings, particularly those designed to meet higher energy efficiency standards, it is necessary to investigate the levels of radon in these residential complexes. Furthermore, considering the period (1970–1988) when the buildings in the present study were constructed, there is a tendency to envelope existing buildings and in this case, it is necessary to assess the radon exposure after the building envelope to evaluate the impact of building sealing on the RAC. As Romania intensifies its efforts to increase energy efficiency, it becomes essential to understand the potential hazards associated with reducing ventilation in energy-efficient buildings. The aim of this study was to investigate the variability of radon concentrations in several multistory buildings and assess the impact of the floor and type of space considered on the RAC. In addition, the study aimed to monitor radon concentrations in residential buildings in urban areas before the implementation of measures such as thermal insulation. By establishing initial radon exposure levels, we aim to prevent unintended risks to human health that could result from increased radon levels due to changes in the building envelope, while ensuring that future energy efficiency efforts do not compromise indoor air quality and the health of residents.

2. Materials and Methods

2.1. Study Area

The city of residence for the county with the same name, Buzău, has a population of approx. 100,000 inhabitants, with most of them living in multistory buildings. The current investigation involved the monitoring of 455 apartments located in 30 buildings in the city of Buzău. Buzău is situated at 101 m above sea level.
Situated in the southeastern region of Romania, the city of Buzău belongs to a complex geological area that lies at the intersection of the eastern Carpathians and the Curvature Subcarpathians [38]. The geology of the region is dominated by the presence of Neogene sedimentary deposits, such as clays, marls, and sandstones that were formed in marine and lacustrine environments in the Miocene and Pliocene eras, which are overlain by Quaternary alluvial and aeolian deposits [38,39]. Quaternary sediments (sands and gravels) are of alluvial origin and form the substratum on which Buzău is built, being deposited during the Holocene by the Buzău River and its tributaries. The sedimentary material comes from the upper and middle areas of the river basin, where erosion has transported sediments from the Carpathians to the plain [39].

2.2. Structural Characteristics and Building Materials

The multistory buildings involved in this study were built during the Communist period, with the median year of construction being 1985, the oldest being built in 1970, and the most recent was in 1988. In terms of floor numbers, the median is 7 floors with one-third of the investigated buildings having at least 10 floors, the highest being 13 floors, at the other extreme being 4 buildings with 4 floors. The dominant building materials and structural elements of the buildings in this study are centered on the use of reinforced concrete as the basic material for load-bearing structures. Reinforced concrete was also used extensively in foundations, structural walls, columns, and slabs, as well as exterior walls. Each building in the study has a ventilation system through ventilation shafts, specific to old buildings constructed during the communist period.
A smaller amount is attributed to brick, mostly utilized in internal partitions as a masonry component. The current study did not include the radioactivity of the building materials; nonetheless, the construction characteristics of the period in which the analyzed structures were built are comparable, with the building materials utilized for each structure being uniformly dispersed throughout the entire construction area.

2.3. Radon Measurement Technique

Radon measurements were conducted using CR-39 nuclear track detectors, which were placed in 455 apartments (one per apartment), administrative offices, and commercial premises located in 30 multistory buildings in the city of Buzău. The monitoring period lasted between 3 and 4 months (October–January). Out of the total detectors, 446 were successfully retrieved, resulting in a loss rate of 2%. After the monitoring period, the detectors were processed at the “Constantin Cosma” Radon Testing Laboratory (LiRaCC) within the Faculty of Environmental Science and Engineering, Babeș-Bolyai University. This laboratory is certified by the Romanian National Commission for Nuclear Activities Control (CNCAN), under designation certificate No. LI 05_LiRaCC_UBB/2021 rev. 1, and operates in accordance with ISO 17025 standard. The measurement campaign adhered to the legal requirements defined in CNCAN President’s Order No. 153/27.07.2023, published in the Official Gazette No. 729/08.08.2023, which supplements and repeals CNCAN President’s Order No. 185/2019 regarding the methodology for determining indoor radon concentration in buildings and workplaces. The experimental results were corrected with seasonal correction factors and are presented in this present study as annual mean values of the RAC. The entire laboratory procedures for processing and reading the detectors have been previously described by Cucoș et al. [24]. The laboratory has consistently participated in international intercomparison exercises, demonstrating the high quality of its radon measurements.

2.4. Statistical Analysis of Data

For the statistical analysis, OriginPro 2024 (OriginLab Corporation, Northampton, MA, USA) software was used. The normality of the data distribution was evaluated using the Shapiro–Wilk (SW) test. Non-parametric statistical methods, such as the Mann–Whitney (MW) test for comparing two samples and the Kruskal-Wallis (KW) with Dunn’s post-hoc test for comparing three or more samples, were used when the data did not show a normal distribution. The degree of association between variables was assessed using Spearman’s correlation coefficient (rS). The variability of the results was expressed through the coefficient of variation, as a ratio between the standard deviation and the arithmetic mean. The significance level α was set at 0.05.

3. Results and Discussions

3.1. RAC at Building Level

In each building, on average of 15 radon detectors were placed, the median number of detectors being 12 with limits between 7 and 46 detectors. Figure 1 shows the RAC according to the year of construction, along with the number of detectors placed in each building (color code), in relation to the number of floors for the monitored building (circle diameter).
The average RAC across buildings ranged between 33 and 77 Bq/m3, with a median of the arithmetic means calculated at the building level being 58 Bq/m3. Descriptive statistics according to the building ID are shown in Table S1. The RAC, displayed as an average value at the building level, shows a normal distribution, an aspect confirmed by the SW test (p > 0.05) and displayed in Figure 2.
As illustrated in Figure 3, a substantial variability of the RAC was observed from one building to another. Thus, the coefficient of variation (CV) showed an average value of 48% with limits between 19% and 103%, where both extremes were specific to four floor buildings.
The difference between them is given by the fact that in the case of the building with high variability (ID 19), one of the apartments was not used during the monitoring period, which led to the accumulation of radon and an RAC of 276 Bq/m3. By removing it, the CV shows a value (55%) close to the calculated average for the monitored buildings. At the other extreme (ID 13), although 3 of the 8 detectors were placed in ground-floor apartments, no significant difference in RAC was observed depending on the floor, an aspect that led to a low CV value.

3.2. RAC at Room Level

Out of the 446 detectors collected, most of them were installed in apartments (372). However, there were also some detectors placed in other areas of the building, such as commercial premises (11%) or administrative offices (5%), specifically on the ground level and mezzanine. The descriptive statistics of the RAC, depending on the monitored room type are shown in Table 1. A statistically significant difference was observed between the medians of RAC according to room type (K = 39.51, p < 0.0001). The results of Dunn’s test revealed that commercial premises have a significantly lower median (30 Bq/m3) than apartments (p < 0.001), and administrative offices (p < 0.001). The median for administrative offices (53 Bq/m3) is identical to the one obtained for apartments, which are usually very poorly ventilated, and the degree of use is occasional. Even when considering the geometric means, commercial premises have a lower value (31 Bq/m3) compared to administrative offices (47 Bq/m3) and apartments (52 Bq/m3).
The mean of the RAC for apartments was 60 Bq/m3 with limits between 11 and 285 Bq/m3. The investigated places did not surpass the reference level of 300 Bq/m3 for RAC, as mandated by national and European regulations. Comparable results were obtained by Cosma et al. [40] when evaluating radon concentrations in 12 Romanian apartments during both warm and cold seasons, obtaining an annual mean of 65 Bq/m3. The distribution of the RAC at the apartment level in the present study follows a log-normal pattern, as confirmed by the SW test on the log-transformed data (p = 0.3). This log-normal pattern was also obtained in the study by Ambrusino et al. [41], where they measured the indoor radon concentration in the Campania region (Italy). The geometric mean of the RAC in apartments is 52 Bq/m3, close to the median value (53 Bq/m3), with a geometric standard deviation (GSD) of 1.7 Bq/m3 (Figure 4). Mócsy et al. [27] achieved a comparable value of 52.9 Bq/m3 in their investigation, which attempted to monitor the radon concentration in a ten-story building constructed in 1965 in Cluj-Napoca. The RACs presented in the study by Vukotic et al. [42] are lower (ranging from 20 to 30 Bq/m3) compared to the present study. In the study by Vukotic et al. [42] it was observed that during the winter season, the radon concentration is higher on the upper floors, and, in contrast, in the summer season it is higher on the lower floors. This is explained by the effect of the chimney in winter and the ventilation and pressure difference in summer.
In the study by Karpinska et al. [9], the average RAC in flats was 43 Bq/m3, which is lower than the mean obtained in the present study (60 Bq/m3).
Higher RACs are reported in the study conducted in Finland by Arvela [43], where the arithmetic mean in monitored flats was 80 Bq/m3, and the average value for ground-floor apartments was 212 Bq/m3.
For the analysis of the RAC distribution according to the building’s floor, only apartments were considered, the commercial premises being found only on the ground floor of the building, and the administrative ones on the ground floor or mezzanine. Among the 372 monitored apartments, approximately 50% of the measurements were distributed between the ground floor (20%), the 1st floor (17%), and the 2nd floor (11%), the rest being distributed with a decrease in their number with an increase in the floor from 9% on the 3rd, 4th, and 5th floors to 4% for the 10th floor, and 1% for floors ≥ 11. Descriptive statistics of the RAC, depending on building level are shown in Table S2. An increase in the RAC medians can be observed for the upper levels compared to the ground floor, respectively on the 1st or 2nd floor (Figure 5). The Dunn test revealed that the median values for the ground, 1st, 2nd, and 5th floors were significantly lower than those for the 6th, 10th, and 11th floors (p < 0.05). These results contradict those presented by Mócsy et al. [27], where a decrease in the radon concentration from the ground to the upper floors was observed. In fact, the authors attribute the radon values from the ground floor and the first floor to the emanation of radon from the soil. In the present study, there was no statistically significant difference (p = 0.16) in the RAC medians between the apartments on the ground floor (49 Bq/m3) and those on other floors (54 Bq/m3). These results also contradict the study by Shaikh et al. [15], where have found the highest radon concentrations in apartments from the ground floor with an average of 40.9 Bq/m3. On the top floor (19th floor), the radon concentration presented an average of only 14.9 Bq/m3. The same trend of decreasing radon concentration at the floor level was also found in the study by Tchorz-Trzeciakiewicz and Olszewski [44], where the average RAC at the lower levels was 68 Bq/m3, and at the upper levels, the average was 16.4 Bq/m3. A similar pattern was also found in the study of Zalewski et al. [14], in which the highest concentrations were monitored in basements (76 Bq/m3) and ground floors (31 Bq/m3), and the lowest on the upper floors (13 Bq/m3). In the study by Senitkova and Kraus [17], the highest average radon concentrations were determined on the first two floors (114 Bq/m3 for 1st floor, 97 Bq/m3 for 2nd floor), and on the 8th floor with an average of 112 Bq/m3.
To identify the cause behind the rise in the RAC as the floor level increases, additional analysis was conducted. Out of the 372 apartments examined, 30 are situated on the highest level. The MW statistical test was performed to compare the RAC for the apartments located on the top floor with the other apartments. The median RAC value (69 Bq/m3) at the top floor was significantly higher than that for apartments on other floors (52 Bq/m3) (p = 0.019). One potential reason could be the presence of shared ventilation ducts in the kitchen, bathroom, and storeroom that run vertically throughout the entire building. These ducts may contribute to the movement of radon gas through the chimney effect. However, the RAC outliers are not specific only to the top floor. In fact, of the thirteen values identified as excessive by the quartile method, only two are located on the top floor. After conducting thorough interviews with the apartment owners, two distinct patterns were identified as being responsible for the high values obtained.
The first refers to either the absence of occupancy in the apartment during the exposure period or inadequate ventilation inside the interior space. Additionally, it includes an increase in the degree of tightness of the apartment due to the installation of thermal insulation on the interior or exterior walls, as well as the use of double-glazed windows.
The second regards the divergence in behavior among owners, with some opting to obstruct the vents, while others choose to utilize them. This behavior resulted in the movement of radon into the indoor area for those who opted to utilize the vents, regardless of whether the apartment was located on the top floor. These apartments were among the few, or the only ones, in the building that still used shared ventilation.
Conversely, very low values (11, 15 Bq/m3) were linked to a fearful response towards the measurement conducted, as the detector was mounted on the balcony, the recorded concentration being specific to outdoor air.
Although this study did not consider elements related to radon concentration in soil, such as radon hazard index and geogenic radon potential, geological data in the literature suggest a relatively high potential, associated in particular with the source area of Holocene deposits, known for their significant radioactive potential [45], but also with a radioactive potential from loessoid deposits, which may contain a significant granitic fraction [46]. Moreover, the maximum values of RAC observed in this study indicate a possible radon problem, including multistory buildings, even on the upper floors, in the context of energy efficiency, and may pose a significant problem in the future if not addressed. In the absence of measurements of the radioactivity of construction materials, it was assumed that their distribution within each building was uniform. As such, the variability found for the RAC is attributable to the circulation of air currents inside the building and the degree of ventilation in each apartment.

4. Conclusions

This paper reveals that in apartment buildings, the higher floors typically have higher RAC, contrary to the results obtained in other studies, mainly due to factors such as poor ventilation or chimney effects.
Indoor RAC varies significantly from building to building, with an average between 33 and 77 Bq/m3. This variation is influenced by factors such as apartment use and ventilation. Commercial spaces have lower radon averages compared to apartments and administrative offices, due to the ventilation present in commercial spaces.
Median RACs increase with increasing floor, contrary to previous studies [9,27,42,43]. This increase can be explained by the chimney effect and the presence of common ventilation ducts that transport radon upwards.
Factors such as occupancy, ventilation practices, and building alterations (building envelope, obstruction of common ventilation) significantly influence radon levels. Apartments that were not occupied or had poor ventilation had higher radon levels, while common ventilation systems could contribute to radon distribution throughout the building.
As Romania continues to develop and construct more energy-efficient buildings, there is concern that thermal retrofits that are not accompanied by increased ventilation could lead to an increase in indoor radon concentrations. The lack of adequate ventilation can reduce air exchange with the outside, allowing radon to accumulate indoors.
Future studies are needed to monitor radon levels after the completion of the thermal retrofit work and compare these results with those of the present study to assess the impact of thermal rehabilitation on radon concentrations. Moreover, inspection efforts are also needed to ensure that measures applied to residential buildings to increase energy efficiency are compliant and do not compromise indoor air quality. These inspections can provide competent authorities with a better understanding of how the renovation process can influence radon levels and emphasize the importance of implementing radon prevention measures.

Supplementary Materials

The following are available online at https://www.mdpi.com/article/10.3390/atmos15111267/s1, Table S1: Descriptive statistics of RAC (Bq/m3) depending on the monitored building, Table S2. Descriptive statistics of RAC (Bq/m3) in apartments according to building level.

Author Contributions

Conceptualization, Ș.F., A.-I.L. and T.D.; methodology, Ș.F., A.-I.L. and T.D.; investigation, Ș.F., A.-I.L., A.C., G.-C.D., M.-C.M., A.C.Ț. and L.C.; writing—original draft preparation, Ș.F., A.-I.L. and T.D.; writing—review and editing, A.C.; statistical analysis, T.D.; supervision, A.C.; project administration, A.C. All authors have read and agreed to the published version of the manuscript.

Funding

The research was supported by the project ID P_37_229, Contract No. 22/01.09.2016, with the title “Smart Systems for Public Safety through Control and Mitigation of Residential Radon linked with Energy Efficiency Optimization of Buildings in Romanian Major Urban Agglomerations SMART-RAD-EN” of the POC Programme in analysis and interpretation of the data.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The raw data supporting the conclusions of this article will be made available by the authors on request. The data are not publicly available due to privacy.

Conflicts of Interest

The authors declare no conflicts of interest. Ştefan, Florică is employee of S.C. RADON CONTROL S.A. The company had no roles in the design of the study; in the collection, analysis, or interpretation of data; in the writing of the manuscript, or in the decision to publish the articles. The paper reflects the views of the scientists and not the company.

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Atmosphere 15 01267 g001
Figure 1. The RAC at the building level, depending on the year of construction. The diameter of the circle indicates the number of floors, and the color represents the number of radon measurements taken in the monitored building.
Figure 1. The RAC at the building level, depending on the year of construction. The diameter of the circle indicates the number of floors, and the color represents the number of radon measurements taken in the monitored building.
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Figure 2. The quantile–quantile plot for the observed data reported as the average RAC at building level (CI = 95%).
Figure 2. The quantile–quantile plot for the observed data reported as the average RAC at building level (CI = 95%).
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Figure 3. The RAC variation, depending on the monitored building. The horizontal red dash line represents the median RAC calculated for all buildings involved in the study (58 Bq/m3), and the diamonds represent the outliers.
Figure 3. The RAC variation, depending on the monitored building. The horizontal red dash line represents the median RAC calculated for all buildings involved in the study (58 Bq/m3), and the diamonds represent the outliers.
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Figure 4. Log-normal distribution of RAC in apartments (n = 372).
Figure 4. Log-normal distribution of RAC in apartments (n = 372).
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Figure 5. The RAC distribution in apartments, depending on the floor of the building. The vertical red dash line represents the median value for RAC in apartments (53 Bq/m3).
Figure 5. The RAC distribution in apartments, depending on the floor of the building. The vertical red dash line represents the median value for RAC in apartments (53 Bq/m3).
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Table 1. Descriptive statistics of the RAC (Bq/m3) depending on the type of monitored room.
Table 1. Descriptive statistics of the RAC (Bq/m3) depending on the type of monitored room.
Room TypeN *Min.A.M.G. M.Mdn.S.D.Max.CV (%)
Administrative office2422514753209139%
Commercial premise5010353130209057%
Apartment372116052533628559%
* N—Number of measurements, Min.—Minimum, A.M.—Arithmetic Mean, G.M.—Geometric Mean, Mdn.—Median, S.D.—Standard Deviation, Max.—Maximum, CV (%)—Coefficient of Variation.
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MDPI and ACS Style

Florică, Ș.; Lupulescu, A.-I.; Dicu, T.; Țenter, A.C.; Moldovan, M.-C.; Dobrei, G.-C.; Copaci, L.; Cucoș, A. Radon Concentration Assessment in Urban Romanian Buildings: A Multistory Analysis. Atmosphere 2024, 15, 1267. https://doi.org/10.3390/atmos15111267

AMA Style

Florică Ș, Lupulescu A-I, Dicu T, Țenter AC, Moldovan M-C, Dobrei G-C, Copaci L, Cucoș A. Radon Concentration Assessment in Urban Romanian Buildings: A Multistory Analysis. Atmosphere. 2024; 15(11):1267. https://doi.org/10.3390/atmos15111267

Chicago/Turabian Style

Florică, Ștefan, Alexandru-Iulian Lupulescu, Tiberius Dicu, Ancuța Cristina Țenter, Mircea-Claudiu Moldovan, Gabriel-Cristian Dobrei, Luana Copaci, and Alexandra Cucoș. 2024. "Radon Concentration Assessment in Urban Romanian Buildings: A Multistory Analysis" Atmosphere 15, no. 11: 1267. https://doi.org/10.3390/atmos15111267

APA Style

Florică, Ș., Lupulescu, A. -I., Dicu, T., Țenter, A. C., Moldovan, M. -C., Dobrei, G. -C., Copaci, L., & Cucoș, A. (2024). Radon Concentration Assessment in Urban Romanian Buildings: A Multistory Analysis. Atmosphere, 15(11), 1267. https://doi.org/10.3390/atmos15111267

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