The influence of public open space enclosure on health : an environmental, psychological, and behavioral study based on public housing estates in Hong Kong

Abstract

Many scholars have identified enclosure as important in both interior and exterior space configuration. Enclosures are even more important in public open space design within a context of urbanization and densely developed cities. However, only a limited number of spatial identifies have been specified and studied, and studies on the topic have rarely been pragmatic. Under such circumstances, spatial identities and their relationship with enclosure should be elaborated. An integral and objective way to measure and estimate enclosure of a certain space based on these identities is needed. In addition, the effects of enclosure on users have not received sufficient attention and need systematically exploration. Health outcomes are on the specific focus in the current study.

Based on previous studies, 18 measurable spatial indicators related to enclosure are selected for further study. Using factor analysis on a sample size of 116 open spaces within or near public housing estates in Hong Kong, 11 of these 18 indicators are identified as being crucial for spatial enclosure. Four principal factors (i.e., scale, H/D relationship, gap, and shape) cover 80.94% of the information on the 11 indicators. Based on Cronbach’s alpha, these factors are proven reliable. The enclosures are further estimated based on the 11 indicators and coefficients using factor analysis. With a subset of 26 spaces, the estimated enclosure is proven as valid and reliable after examination of Cronbach’s alpha by 200 untrained (without architecture-related professional training) and 63 trained (with architecture-related professional training) subjects.

Major spatial indicators of enclosure are further studied for detecting potential health-related influence on subjects. Methods of questionnaire survey, quasi-experimental questionnaire survey, and observation are employed. The examined three aspects of health outcomes are physical, psychological and social. Based on 178 untrained and 63 trained valid samples in questionnaire survey, statistic correlation between spatial enclosure and health outcomes are identified, although still general and insufficient in explaining the exact relationship between them. Specifically, brighter, larger, more coherent, mysterious or legible space may be more inspiring for feeling or behavior that leads to positive health outcomes, whereas complexity does not seem to be correlated with the three categories of health feedback. With a sample of 109 college students, a quasi-experimental questionnaire survey confirms that perceived spatial enclosure and feelings can be influenced by spatial identities of scale of space, height, width and density of enclosing materials. Such results further confirm and elaborate the influence of enclosure on mental health. According to observations in 7 out of the 26 spaces, certain enclosure characteristics, such as foliage and overhead shelters, scale of immediate space and its visual extension, together with relationship between target space and its surrounding environment, are likely related with the emotions and behaviors of users. Thus, the effects of enclosure on the physical and social health of users are likely to be true.

Although this study and its generalization have many limitations, it achieves two major goals and proposes several design implications for landscape practice. Generally, realizing health-beneficial urban open space is possible through enclosure design.