2.1. The Protective Action Decision Model (PADM)
The PADM is one of a few influential theories that explain how decisions are made in risky situations [25
]. Other theories, such as the theory of planned behavior [26
] and the theory of protection motivation [28
], focus more on individual risks and personal health contexts. Designed for and applied to collective risks and mass emergencies, the PADM is particularly useful for understanding behaviors in a nuclear accident scenario, which is the context in which it was first applied [13
]. However, this model has also been used in studies on other types of collective risks, such as wildfires [29
], chemical release from the petrochemical industry [30
], city smog [31
], flood hazards [32
], and the ‘not-in-my-backyard’ attitude to nuclear power plants [33
The PADM combines a wide range of factors that influence household decisions if a threat occurs. Overall, this theory assumes that people’s access to and assessment of cues in and information from their living environments, social contacts, media, information channels, and risk messages play a role in how they value and manage risk. People’s characteristics, including demographic data, also play a role. Central to the model is the assessment of exposure, and thus susceptibility, to risk. This stage includes what it is about a risk that people pay attention to and comprehend. Based on this, it is assumed that citizens form perceptions about the severity of a risk, about the feasibility and effectiveness of measures, and about the actors who are involved in the management of a risk. More than one measure may seem reasonable. If a nuclear accident occurs that threatens a community, the stakeholders not only include the authorities and the media, but also the independent experts, the company that operates a nuclear plant, and all of the affected households [25
]. Taken together, these considerations are assumed to shape protective action decisions. However, preferred decisions are also conditioned in everyday life. The model includes situational factors that facilitate or hinder the realization of desired decisions.
The scope of the model also means that most of the studies focus on parts of it or specialize in certain areas, such as risk communication [30
] or evacuation modeling [34
]. Our paper notes Lindell and Perry’s [25
] remark that “it is still not entirely clear what motivates people to take protective action”. Although a set of factors is highly relevant, we know less about whether risk perception is a strong determinant vis-à-vis protective action perceptions or other considerations. More accurate knowledge could inform risk communication efforts, so the issues that most likely ‘move’ an issue from audiences’ perspectives are also the ones that are emphasized in government communication. We limited this study’s focus to examining the extent to which a preferred place of residence after decontamination is affected by perceptions of (a) threats, (b) protective action, (c) stakeholders, and (d) the situational factors that facilitate or impede a preferred action.
2.2. Research on Citizens’ Responses and This Study’s Research Hypotheses
Extant research demonstrates that certain demographic factors affect the decisions to move or stay after nuclear accidents that lead to radioactive contamination. Those who, to a greater extent than others, tend to leave areas affected by radioactive material and do not return are women, parents with at-home children, and people with higher socioeconomic status [18
]. Women and parents expressed greater concern about the negative health effects of ionizing radiation, which justified risk-avoidant behavior, such as settling somewhere not affected by a radioactive release [14
]. Beyond the demographic factors, such as various contributing aspects that can be actualized using the PADM, the state of knowledge is more uncertain.
According to lay opinion, radioactive material disseminated in connection with nuclear power accidents is particularly dangerous [39
]. They rate it at the top among other so-called dread risks [10
], and as a possible hazard for decades to come [18
]. Citizens perceive ionizing radiation as particularly unpleasant and dangerous, because they associate it with disasters in which many have been negatively affected and the outcomes have sometimes been cancer and fatalities. They also perceive radioactive substances as difficult to control, even for the expert authorities [9
]. It was also shown after the Fukushima accident in Japan that perceptions of high risk and concern about ionizing radiation predict a greater tendency to move from a decontaminated area [13
]. There is no reason to believe that a similar association would not be found in the Swedish scenario.
The perception of more serious threat characteristics is associated with less propensity to return to live in a decontaminated area.
A study about citizens from the Fukushima prefecture showed that awareness of the remediation area having been declared safe from radiation benefited relocation [17
], which was expected. However, the same study tempers the expectations of return rates after decontamination because it also shows that the cancellation of evacuation orders after remediation had a much lesser effect than the termination of allowances for housing and living expenses for evacuees [17
], indicating that household finances play a more significant role than decontamination. Another study showed that decontamination had a statistically significant effect on the return level, but that the measure itself caused less than 8% of all of the evacuees to return [18
]. These two studies thus suggest that decontamination has a statistically significant but still rather weak effect. Citizens’ uncertainty regarding the health effects of low-dose radiation achieved with decontamination can be sufficient motivation to not return [14
]. Regarding food safety after the Fukushima accident, it was shown that those who believe that the current safety standards in Japan are sufficient are less risk-averse when it comes to protective action decisions concerning food [42
]. Like food control, decontamination is carried out based on safety standards.
Belief in the effectiveness of decontamination is associated with a greater propensity to return to live in a decontaminated area.
In different ways, the studies have focused on the importance of stakeholder perceptions. A study by Tateno and Yokohama that focused on the Fukushima residents showed that mistrust of responsible government institutions mediates worry over radiation [43
]. Another study found that a sense of injustice and being treated unfairly—thus lower trust in responsible government agencies—motivates citizens not to follow the recommendations to return [38
]. Zhang et al. concluded that distrust of government information is associated with permanent migration [14
]. An analysis of qualitative interview data further adds that governments and authorities can be seen as remote bureaucracies trying to decide in a crisis in which they bear no health risk [44
Trust in information from government agencies is associated with a greater propensity to return to live in a decontaminated area.
Citizens’ assessments of the importance of social relationships influence settlement-related decisions [36
]. In a study on citizens’ reasons not to return from a temporary housing community, Orita concluded: “The most commonly articulated reason for staying in temporary housing was the sense of community that they had built” [36
]. However, if someone has family members living in a decontaminated area, the chance of returning increases [17
]. In other types of crises, social ties have also proved to be important for household decision-making [45
]. Stakeholder perceptions thus include citizens’ assessments of the importance of their peers’ positions on the issue of whether to return.
People who attach importance to others’ assessment of the settlement choice are likelier to return to live in a decontaminated area.
Finally, decisions on where to settle involve several factors that may impede or facilitate a preferred settlement choice. Studies have found that individuals’ finances are significant for their choice of residence after a nuclear accident. In areas that have not been as affected by radioactive contamination as others, such as coastal areas, a high socioeconomic status predicts a higher return rate [37
]. However, in more heavily contaminated areas, a high socioeconomic status predicts a lower return rate [18
]. Thus, if finances were not a concern, more people would be likely to stay away from contaminated neighborhoods. A lack of financial resources has also been shown to prevent people from moving from radiation-affected areas during the year following an accident [20
]. This importance of finances was also demonstrated when canceled evacuation orders did not significantly increase the rate of relocation, but the termination of financial compensation and housing subsidies for evacuees did [17
]. Thus, the household economy is one of several situational factors that affect settlement decisions. In particular, a lack of financial resources prevents a number of citizens from making their preferred settlement choices. Owning property and depending on a job in an affected area predict a greater likelihood of returning [17
], but the same could apply if better means of subsistence exist elsewhere. Zhang et al. demonstrated that people are motivated to move permanently if better job-market opportunities are identified elsewhere [14
]. Results from an interview study similarly demonstrated that a better job market and educational opportunities in cities not affected by a nuclear accident motivated young adults to migrate [38
If people feel attached to their hometown through work, schools, investments, and so on, they are likelier to return to live there after decontamination.
Just as access to work is important for settlement decisions, so are schools and other community services [17