## 5 Discussion and Conclusions  
In Seoul, it is inadvisable to go out on any day, except in summer, as a result of the PM concentration and its effect on human health. When the WHO standard is applied, the concentration of PM in Seoul is revealed to be remarkably high and cases of excessive concentration exceeding the daily average atmospheric environment standard are also frequent. The government has been pursuing various policies to reduce PM concentration but the concentration of PM has not improved to the extent that people recognize any change. Research has shown that most people believe PM to be an important problem but do not undertake enough mitigating behaviors to prevent its occurrence. Reliable research should be preceded by an analysis of cause and effect before the preparation of PM countermeasures. We sought to understand residents' perceptions of PM, their response behaviors and the psychological causes of these behaviors; the main findings of this study are as follows. First, to identify the perceived indoor air quality of the residents, the questionnaire was distributed at a time when the concentration of PM had been significant throughout the year; thus, residents' interest in indoor air quality was great. However, despite high outdoor concentrations of PM, the indoor air quality was not considered poor or dissatisfactory. The symptoms that residents attributed to PM were not physical, such as allergies or bronchitis. They more commonly experienced psychological stress or anxiety, feeling that PM had a negative effect on health and was interfering more frequently with daily life, in that residents were going out less often to avoid it. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Variable** & **B** & **Std Error** & **Beta** & \(t\)**Value** & \(p\)**-Value** \\ \hline Constant & 8.103 & 3.577 & & 2.265 & 0.025 \\ Knowledge of PM & 0.630 & 0.443 & 0.095 & 1.424 & 0.156 \\ Psychological attributes & 0.373 & 0.082 & 0.375 & 4.555 & 0.000 \\ PM-related symptoms & 0.191 & 0.070 & 0.219 & 2.737 & 0.007 \\ \hline \hline \end{tabular} Note: R = 0.55, R\({}^{2}\) = 0.31, Adj. R\({}^{2}\) = 0.30.  
\end{table} 
Table 12: Multiple regression analysis of the response behaviors to particulate matter. Figure 7: Residents’ psychological influences. Second, the problem with the PM-related behaviors of residents in Seoul was that many people did not take actual action despite their willingness to do so. Mitigating behavior to try to minimize PM generation was less common than adaptive behavior to protect individuals from the risks of PM. This may have been because of the nature of mitigating behavior, which often entails loss or inconvenience. Even if the risks associated with PM were largely recognized, it would be necessary to compensate for the loss when the habitual behavior of individuals was abandoned in favor of following the recommended behavior. Unlike preventive actions to protect individuals from PM, compensation for mitigating behavior is only likely to be achieved in the distant future and even then, such compensation would provide a social rather than an individual benefit. This suggests that more persuasive strategies should be employed to stimulate changes in individual behaviors for collective interests. Third, the psychological characteristics of individuals can either hinder or promote action for environmental sustainability. The greater the perceived risk and the more psychological that risk, the more likely it is that an active response will occur. Analysis of the psychological factors affecting residents in Seoul revealed that they perceived the risk of PM to be very close (in terms of psychological distance). However, despite revealing significant levels of risk perception and psychological distance, the results of this study did not show active response behaviors. Attention must be paid to the externalizing of responsibility among the psychological causes of this lack of action.