Setting the Scene for a Healthier Indoor Living Environment: Citizens’ Knowledge, Awareness, and Habits Related to Residential Radon Exposure in Romania

: The present research is based on the premise that people perceive radiation risks in different ways, depending on their cultural background, information exposure, economic level, and educational status, which are speciﬁc to each country. The main objective was to assess and report, for the ﬁrst time, the Romanians’ attitude (perceptions, knowledge, and behaviors) related to residential radon, in order to contribute to the creation of a healthier living environment. A convenience sample of 229 people from different parts of Romania, including radon prone areas, was used. Results proﬁled a population vulnerable to radon threats from the perspective of their awareness and perceptions. Thus, study results showed that most participants did not perceive the risk generated by radon exposure as signiﬁcant to their health; only 13.1% of interviewed people considered the danger to their health as “high” or “very high”. Additionally, it was found that awareness of radon itself was low: 62.4% of the sample did not know what radon was. From a practical perspective, the study shows that in Romania, increasing awareness, through the provision of valid information, should be a major objective of strategies that aim to reduce radon exposure. The present study takes a bottom-up perspective by assessing Romanian citizens’ attitudes toward radon. Therefore, it compensates for a gap in the behavioral studies literature by providing practical support for radon risk mitigation and creating the premises for a healthier living environment. contributing to the reduction of radon exposure. The results cast light on positive attitudes of


Radon as an Environmental Risk to People
Radon awareness and perception have been the focus of human health and environmental public debate over the last thirty years. Risk perception is mediated by beliefs about the existence and characteristics of the hazard and it is acknowledged to influence behavior change [1]. Radon is a naturally-occurring radioactive gas, present in soils, rocks, and water, that penetrates buildings, being, therefore, inhaled by the residents. In addition to the geological substrate (geological conditions), other main radon sources include anthropogenic factors, like building construction and materials, tap water, and living habits [2][3][4]. As radon is not stable and decays, it exposes the human body to radiation [5]. Radon is considered as one of the top four environmental risks to public health [6] and many occupational and epidemiological studies have investigated the links between chronic exposures to radon and lung cancer [7]. The World Health Organization (WHO) showed that between 2% and 12% of all lung cancer deaths in the EU were related to radon and that, for instance, the total number 200 Bq/m 3 . Directive 96/29/Euratom established basic safety standards (BSS) for the protection of the health of workers and the general public against dangers arising from ionizing radiation, but without including exposure to radon in dwellings [25]. The basic principles of protection against radon have been updated and consolidated in the BSS Council Directive 2013/59/Euratom, which will have to be transposed by 2018 [27]. According to Article 1 of the abovementioned Directive, its aim is to establish uniform basic safety standards for the protection of the health of individuals subject to occupational, medical, and public exposures from the dangers arising from ionizing radiation. Although radon measurements and human health protection programs already have a long history in some countries (for example, Sweden has had mandatory radon protection measures since the 1980s [28]), in other European countries (like Romania), research focused on radon measurements and the creation of radon maps is relatively recent [2,29], and, in this context, attitude studies, such as the present one, are relevant and useful.
For many European countries, including Romania, protection against radon started in the context of radon water regulation. At the end of 1998, Finland, Sweden, the Czech Republic, Russia, the Slovak Republic, and Romania had limits for radon in water. The reason why these countries introduced reference levels for radon in water is that they often relied on water supplies from wells drilled into crystalline bedrock, many times granites with enhanced uranium content [25]. High radon concentration levels above 1000 Bq/l, and even higher than 20,000 Bq/l, were found in several thousand wells in all of these countries [25]. These earlier radon water provisions were the foundation for supporting the transposition into Romanian legislation of Directive 2013/59, materialized in Law No. 301/2015 on establishing the requirements for the protection of human health as regards radioactive substances in drinking water (parameter value radon is 100 Bq/l; when radon concentration exceeds 1000 Bq/l, corrective actions must be carried out to ensure radiation protection, but extra analyses are not required) [30]. The importance of this legal provision is highlighted by the fact that a level of 1000 Bq/l of radon in tap water will increase, on average, the indoor air radon concentration by 100 Bq/m 3 [31]. Reduction of radon concentration in water can be made through aeration of the room where water is stored and through dilution (mixing high radon concentration water with low radon concentration water), while water treatment installations have little effect [32]. However, radon water regulation is not the only activity for radon mitigation. There are various radon risk mitigation strategies that offer different ways to reduce the level of indoor and/or outdoor radon. These include soil suction, sealing cracks and openings, house pressurization, and heat recovery ventilators (HRV), and they vary largely in terms of complexity and costs.

From Risk Perception to Environmental and Radon Risk Perception-Conceptual Framework
The definitions of risk are abundant in the literature and many scholars have strived to find the most appropriate way of classifying different risks in various academic fields (social risk, economic risk, safety risk, environmental risk, or political risk). Therefore, due to its multidimensional and nuanced nature, a common definition of risk is difficult to develop. From an economic perspective, for example, "risk is a piece of information about a frequency distribution that, together with expected value, serves as an imperfect substitute for the density function in prescribing or explaining choice under uncertainty" [33]. The notion of risk involves, according to Stanley Kaplan and John Garrickboth [34], uncertainty and some kind of loss or damage, and risk is "probability and consequence". In order to have a uniform interpretation of risk-related concepts, the understandings hereafter are adopted. A "risk" is defined, according to the European Union guidelines, as the probability that an event will occur and generate negative consequences [35]. The hazard is a dangerous phenomenon, substance, human activity, or condition that may cause loss of life, injury, or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage [36]. Paul Slovic [37] emphasizes that the study of risk perception must examine how people characterize and evaluate hazards. Adopting the meaning used by O'Connor et al. [38], "risk perception" is understood in the current study as the perceived likelihood of negative consequences to oneself and society from a specific environmental phenomenon, such as an in-house radon presence (an environmental risk). It is observed that the perception of risk from radon gas is positively related to other perceptions of the environment [39]. Environmental risk represents the probability to suffer potential negative effects due to changes in the environment [40]. Environmental risks form a distinct group and have specific features: high levels of uncertainty and uncontrollability, strongly delayed consequences, and consequences that occur at distant places and that are, therefore, often borne more by others than by the ones who caused them [41].
In the same way that value systems or the understanding of a need depend on collective and individual mental representations, and may differ over time and places [42], risk perception is conceptualized as a social construct and not as an objective property of a hazard or event ( [43][44][45]). Thus, being, in part, a product of social experience, including communication about the consequences of potentially hazardous events [45], risk perception varies in terms of the degree to which people experience fear, lack of knowledge, or control [46]. Risk perception is considered a subjective assessment of the occurrence of an unfavorable event and of the concerns about the subsequent outcomes [47]; therefore, risk perception is relative to the observer, and it is a subjective thing, i.e., it depends upon who is looking [34].
In line with this last-mentioned understanding of risk perception, a specific study of Romanians' perception of radon risk is essential because the results reported in other countries cannot be extrapolated to the Romanian population (due to inherent cultural, economic, or social differences). Additionally, global and local scale analyses are complementary for risk management [48]. At the same time, such research supplies indispensable information to any awareness-educational campaign and to decision-makers responsible for designing and implementing health and environmental public policies by signaling that those who invest more in education are able to make better choices in critical situations [49].
The variables analyzed in the present study outline Romanian citizens' attitudes toward radon (as an environmental risk). For the present study, attitudes were investigated by taking into account radon awareness, radon risk perception, willingness to pay (WTP) for protection against radon, willingness to accept (WTA) actions for reducing radon risk exposure, and behaviors. Attitude can be beneficial or prejudicial both for individuals and at a societal level, impacting on radon (environmental) risk management and communication. Thus, for example, an attitude that incorporates high awareness of radon and radon risks, WTP and WTA actions for limiting radon risk exposure, and behaviors that lead to a reduction of radon levels in homes is likely to generate positive outcomes.

Research Aims
Despite addressing radon exposure risks by a substantial body of literature, few studies are dedicated to citizens' attitudes toward radon. Radon risk prevention and reduction are possible only if knowledge generated by medicine, chemistry, or physics is corroborated with that from social sciences, as humans are the main actors of the prevention and reduction measures [50]. Environmental risk perception is considered as a powerful determinant of people's environmental behavioral intentions [38] and, consequently, understanding perceptions, awareness, and actions becomes a pillar in the development of public policies and communication strategies focused on radon.
The present study takes a bottom-up perspective, being the first to assess Romanian citizens' attitudes toward radon and, thus, compensates for a gap in the behavioral studies literature by providing practical support for radon risk mitigation and creating the premises for a healthier living environment. Therefore, the goal of the article was to find out community-related information that would contribute to the prevention of radon consequences. At the same time, the availability of this information (such as low risk perceptions) justifies intervention measures designed to ease the transposition of the new European Union radon basic safety standards into national legislation. The main objective of the study was to assess and report the Romanians' attitude (perceptions, knowledge, and behaviors) related to residential radon.
An original feature of this investigation is brought by the aggregation of all studied variables (Table 1), dedicated to a geographical space (Romania) that faces radon risks. The risk is reflected by previous research that showed that indoor radon concentrations for about 30% of all studied dwellings exceeded the threshold of 300 Bq/m 3 , recommended as a reference level by the ICRP [51,52]. Table 1. Specific objectives of the study and investigated variables.

Objectives Variables
(a) to evaluate radon-related awareness, which includes variables a.1 and a. 3. rapidness of the manifestation of negative health consequences for those exposed to radon b.4. seriousness of death risk for those exposed to radon b.5. danger degree for the subject himself/herself if he/she is to be exposed to radon in his/her home b.6. danger degree for children (living there) if they are to be exposed to radon b.7. danger degree for neighbors if they are to be exposed to radon in their homes b.8. radon accumulation sources in houses b.9. level of radon accumulation in subject's house (c) to evaluate the WTP and the WTA actions for reducing radon risk exposure, considering variables c. 1

Methods
Information about Romanian citizens' behavior, perceptions, and knowledge related to radon in residential environments was obtained using a survey that investigated the variables indicated in Table 1 and the questionnaire from Appendix A.
The evaluation of the way people relate themselves to radon starts with radon awareness, which should include, besides the awareness on this chemical element, awareness of radon measurements; the reason is that awareness of radon measurements influences the risk perception of the interviewed person (variables a.1, a.2). The perspective of Brewer et al. [53], in which the perceived risk has three components-perceived likelihood, perceived severity, and individual vulnerability-was incorporated in the present analysis (variables b.3, b.4, and b.5-b.7), and it was extended to create a more complex view of the perceived risk (for example, taking into account both the present and future dimensions of the extension of the consequences: variables b.1, b.2, b.8, and b.9). WTA, WTP, and other behaviors are possible indicators of the likelihood of acting toward risk reduction; this is the reason why they were included in the analysis (variables c.1-c.3 and d. 1-d.4).
The sample was a convenience one and it contained 229 individuals from the western part of Romania, which also included a radon-prone area. Within the sample, 69% of participants were students, 13% of the entire sample was composed of students with an environmental education profile, and 31% of the sample included non-students. Students were used as part of the sample because they are an important group in the society and they are, or will be, in the near future, players in the housing market, so their attitude toward housing-related health risks influences their house buying and maintenance behaviors. It is not rare to find samples made of students within the field of attitude studies [54][55][56][57]. The results cannot be extrapolated to the entire Romanian population, but they may serve as a reference point in the elaboration of future research dedicated to radon. Given these features of the sample, this study is a first attempt to address the issue of radon risk-perception, which may just be useful for more ambitious projects to be eventually carried out with a representative sample of the population.
Data was analyzed in Excel (Microsoft, Redmond, WA, USA) and SPSS (IBM Corporation, Armonk, NY, USA). The Mann-Whitney U test was used to compare differences between two independent groups when the dependent variable was either ordinal or continuous, but not normally distributed. The Wilcoxon signed ranks test was applied to analyze the difference in the median of a dependent variable between two related groups, and Spearman's rank-order correlation coefficient investigated the strength and direction of association that existed between two variables measured on at least an ordinal scale. The level of statistical significance was set at p < 0.05.

Radon Awareness
The first condition to eliminate or reduce a risk is to be aware of it [58]. Consequently, the first tested variable was the awareness of the existence of this chemical element. The respondents had a very low awareness level of radon (37.6%, Table 2). This level is considered low in the context of the sample structure. One hundred percent of the students from the environmental profile faculty and 37.5% of the students from other faculties (economic and agricultural profiles) were aware of radon and nobody (0%) of the rest of the sample (non-students) was aware. There is a statistically significant difference concerning the awareness of radon between the environmental faculty profile students and the rest of the interviewed people. At the same time, awareness of radon measurements is extremely low ( Table 2).

Perceptions Related to Radon
After people responded to the questions related to radon awareness (Table 2 and Appendix A), a brief explanation about radon was provided to them by the interviewer. Radon risk perception was very low within the analyzed sample. It was assessed by asking participants how many people they thought were/would be affected by radon (in the present, on one hand, and in the future, on the other hand). Thus, the number of persons considered (by the interviewed people) to be affected up until the present by radon is low and very low in the opinion of 92.6% of tested citizens, and the number of those that are likely to suffer in the future because of radon exposure is perceived as low and very low by 81.3% of interviewees (variables b.1. and b.2., Table 3). People might perceive vulnerability to risks of various groups as being different. This is the reason why perception of the vulnerability of several groups was tested, using the Wilcoxon signed ranks test (Table 4, Appendix B). If they are found, significant statistical differences may indicate possible targets for communication campaigns. Regarding the perception of radon danger exposure in terms of health deterioration (variables b.5-b.7, Table 3), the respondents considered children as more vulnerable than the rest of the population (p < 0.05), but they did not make a difference regarding the risk between themselves and other people in the neighborhood, nor between themselves and children (p > 0.05; Table 4, Appendix B). While 17% of the sample evaluated health deterioration risk to be "high" and "very high" for children, only 13.1% and 10.9% of them, made the same appraisal for the risk concerning themselves and their neighbors, respectively. Consequently, protection of children health can be a motivational factor for stimulating behaviors oriented toward radon risk reduction within future communication strategies.
Concerning gender differences in relation to radon risk perception, similarly to Mainous et al. [39], who observed that women were more likely than men to perceive the risk from radon (3.5 times more), the present analysis revealed that Romanian women perceived a larger extension of the danger than men (variables b.1. and b.2. described in Table 1) (p < 0.05; Table 5, Appendix B). However, for the other variables (b.3.-b.8., described in Table 1), gender did not seem to be a significant factor in creating perception differences (p > 0.05).
As well, there was a statistically significant difference between the group of people who heard about radon prior to this survey and those who did not (p < 0.05; Table 6). The former group showed higher evaluations than the rest of the sample in the case of: perceived extension of the danger in terms of people affected (presently and in the future-variables b.1., b.2, Table 1) and seriousness of death risk (variable b.4, Table 1). This finding implies that, from a practical perspective, information and education campaigns may have a positive role in shaping a correct behavior related to radon risk. The same result was reported in a USA survey, where those who had already heard of radon believed that it posed health risk [39].

Ranks
Test

Willingness to Pay for and Willingness to Accept Actions to Reduce Radon Risk Exposure
WTP is generally understood as the amount of money an individual is willing to pay for a good (as this kind of improvement works to protect the homes against radon in this case). WTA is considered the amount of money that people accept to receive or the uncomfortable situations, in the present case, that people are willing to put up with in order to reduce radon risks. WTP and WTA are often investigated to predict behaviors related to environmental aspects [59][60][61][62]. Their inclusion in the present analysis aimed to find out if investigated citizens can be partners in future radon risk-mitigation strategies. Almost half of the sample was not willing to pay anything for protection against radon risks. This finding is in accordance with the low awareness of radon and the perception of a reduced radon risk (Tables 2 and 3). Around one third would pay a small amount of money for this purpose. However, most of them (71.6%) declared that if they had received public financial support, they would have started the works shortly (Table 7). A price of 55 Euro for improvement works may be estimated as high, given that the average gross salary in Romania is around 600 euro (Law No. 340/2015) [63] and that around 63% of the income is spent on food, non-alcoholic beverages, clothing, shoes, and utilities [64]. Almost all the interviewed citizens said "yes" to the idea of accepting a test if it was for free. Table 7. Willingness to pay (WTP), for radon protection through improvement works; and willingness to accept (WTA), a free radon test and starting subsidized radon protection dwelling works (percentages of total sample). For Romanians, a statistically significant difference to pay for remediation works was found between those already aware of radon and the rest (p < 0.05, Table 8): those aware were willing to pay more for remediation works. However, WTA (a test or remediation works) was not sensitive to previous awareness (p > 0.05, Table 8), nor to gender (p > 0.05). At the same time, women declared they would pay higher amounts of money for radon house protection than men (p < 0.05), likely due to a higher concern for health issues. Table 8. Mann-Whitney U Test results for differences regarding WTP for remediation works between people who previously heard about radon and those who did not. Spearman's rho correlation coefficients were calculated and a positive correlation (with weak or medium strength) was observed between WTP for protection against radon and each of the perceptions related to risk-represented by variables b.1.-b.7. (Table 9). This means that the higher the perceived risk is, the stronger the WTP for radon protection becomes. A low perception of radon danger, in general, impacts people's WTP for protection and the observed low correlation (previously mentioned) is a confirmation of this status quo. Table 9. Spearman's rho correlation coefficients for testing strengths and the direction of the relationship between variable c. 1. and each of variables b.1.-b.7.

Other Behaviors with Significant Impact on Radon Risk Exposure
Daily proper aeration influences the quality of the indoor environment by reducing radon concentration, and this is the easiest way to reduce radon accumulation [65,66]. If it is accepted that 'hazard' means the source of a risk [67], then specific behaviors are considered hazards that influence the level of radon risk on peoples' health conditions. Consequently, two seasonal (summer and winter) habits were tested, due to high temperature differences between them that greatly influence aeration propensity (Table 10). More than one-third (36.7%) of the sample indicated an aeration period longer than 12 h/day during summer, while a similar percentage aerated only between 6 and 15 min in winter (Table 10). A Wilcoxon test confirmed that there was a statistically significant difference between the time the windows stayed open during winter and summer (Table 11). Table 10. Habits which influence radon risk exposure: aeration time in summer and winter, duration of peoples' residence in the locality until present, and the duration of intended future residence in the locality (percentages of total sample). Residency duration in the same place can pose a significant negative impact on health in the case of existing threats. For the study sample, long periods of over 10 years dominate both history and intention of future residency: more than 70% of the sample lived for more than 10 years in the same house and intended to continue to stay there. Thus, health risks increase where radon is present in high concentrations.

Discussion
Awareness level varies greatly across countries and studied populations. Similar to the findings of the current paper, a French study reported that 61.9% of the interviewed persons declared that they never heard about radon's presence within dwellings [68], and the French Cancer Barometer 2010 discovered that only 20% of people between 15 and 75 years old (within a random sample of 3359 individuals) knew that radon was a naturally-occurring gas [69]. Other research indicated findings contrary to those observed here: Duckworth et al. [70] showed that 97% of tested residents (from a total of 420 USA households) were familiar with radon, but 75% of respondents were not sure whether radon was a health hazard in their neighborhood. In Iran, almost 67% of respondents (from a total of 462 people, in a 2013-2014 survey) had heard about radon before the study [71].
Many studies revealed low awareness levels of radon risks, such as the ones found in this investigation where only 35% of tested Romanians considered the radon death risk "high" and "very high" (variable b.4., Table 3). In Canada, a country with almost 10% of lung cancer deaths caused by residential radon exposure, a survey on homeowners (on 152 persons) signaled that most respondents had little knowledge and concern about radon and its health effects [72]. In USA, more than a third of the subjects underestimated the seriousness of health effects of radon exposure, 39% disagreed that being around less radon would improve the long-term health of their children, and 52% were unsure whether radon could cause health problems [16]. Additionally, in an earlier investigation in the USA, Weinstein et al. [73] showed that respondents were not claiming that their risk was low because they did not smell radon (81.8% realized that it had no odor) or because they did not experience any physical symptoms. Opposite perceptions were also present: for instance, in Iran, the appraisals were higher, with 83.5% of respondents recognizing it as being hazardous and 34.5% identifying lung cancer as the main health outcome of exposure to radon [71].
Indoor radon exposure can be reduced through proper prevention or mitigation measures that can be grouped into: (i) construction/remediation actions (sub-slab depressurization, passive or active, with discharge open above the roof; natural ventilation; etc.); (ii) day-by-day habits (aeration through windows and doors); and (iii) exposure through the duration of living in the same place. Different studies have proved the effectiveness of the construction/remediation actions. In Finland, prevention construction measures helped in decreasing indoor radon concentration by 47% in provinces with the highest concentration and by 26% elsewhere in the country. Health Canada estimated that it cost around $1000 USD to complete the renovations required to reduce radon risk in an average home [74], and in England, among 767 households that carried on remediation works, 52% of them paid less than 500 pounds [75]. Such results demonstrate that construction measures should be regarded as economic investments that also have positive effects in reducing moisture levels and contamination with other contaminants from the soil [76].
High levels of WTA-subsidized improvement works (observed in the present investigation) indicate that such actions can be implemented in radon-prone areas in Romania (variable c.3., Table 7), contributing to the reduction of radon exposure. The results cast light on positive attitudes of Romanians toward protection if the monetary problem was solved with the aid of public intervention. Other studies took into account a radon level test paid by users and revealed various attitudes relating to WTP and WTA. In Iran, 70% of the people already aware of radon risk were willing to test their houses [71]; in the USA, most were unsure (8%) or were not planning (48%) to conduct radon screening on their own [70]; and in Canada, only 4% of the population had ever tested their homes for radon [77].

Conclusions
This study presents itself as a frame of reference for decision-makers to develop community-based solutions in relation to radon-in accordance with the proximity principle. This principle requires the adoption of decisions as close as possible to citizens-grounded on an understanding of what people think, feel, and do [78]. To this end, the research offers a complex image of the investigated people, structured on four coordinates: (i) radon awareness, (ii) risk perception, (iii) WTP and WTA, and (iv) other behaviors with a significant influence on the level of radon risk on peoples' health conditions.
These results revealed a potentially vulnerable population to radon exposure, especially in light of their lack of awareness of radon health risks. Generally, it can be stated that radon is not perceived of as a relevant health risk by most tested people, as long as only a reduced share of them consider the degree of danger regarding the deterioration of their own health as "high" and "very high" in cases in which they were exposed to radon. Radon awareness and perceptions, which have predominantly low levels among respondents, clearly state the need for information adapted to the specificity of the Romanian population. WTP for protection against radon was low, but the situation was partially compensated for by a very high willingness to accept a test and willingness to undergo remediation works in case the financial burden was assumed by the state or another entity. Aeration of the house, largely adopted by surveyed individuals, is a helping pillar in reducing radon exposure for the population at risk who has limited financial resources with which to cope with it. However, in general, high awareness, perceptions of radon threats, intentions, etc., are not a guarantee that a behavior directed toward the mitigation of risk will be put into practice by the holders of these perceptions, as other factors (such as situational obstacles) might intervene [79]. If these reported low levels of awareness were obtained from a sample mostly made of educated people, with high access to information, it can be assumed that the awareness is even lower within the general population, making it all the more necessary to develop education-information campaigns or other measures that aim to create a healthier indoor living environment for citizens. Reduced awareness (Table 2) is the engine that generates such perceptions related to radon risk. Therefore, increasing awareness should be an important objective of programs targeting radon risk-mitigation, along with the funding, measurement, or implementation of technical solutions. The evaluation of the radon threat and of radon levels can be used as an indicator of intentions to act in order to reduce radon indoor accumulation, as was mentioned by Weinstein and Sandman [79].
On the basis of this first assessment of Romanian citizens' attitude toward radon, the authors propose a further extension of the study by using a representative sample of the population at the country level. In addition, it would be also useful to focus on the work environment (besides the residential one tested here).
These results, corroborated by the Romanian radon map, support the development of de lege ferenda proposals, which is the next desirable stage, in order to completely fulfil the objectives of Directive 2013/59/Euratom. Future research should focus on how to create a mix of instruments-legal, economic, and technical-to reinforce the total effects of each component more effectively, leading to beneficial consequences for every national specific context. Such studies should also investigate to what extent each instrument can contribute to the total mitigation.