Objective  The spread of the COVID-19 epidemic has affected people's physical and psychological health worldwide. To prevent the epidemic from spreading to campus, all colleges and universities in China were asked to offer online courses for students to help postpone them returning to campus in the early stage of the epidemic. However, a small number of students had to stay on campus due to the lockdown of their hometowns for purpose of epidemic prevention and control. With the gradual stabilization of the epidemic, the college students previously quarantined at home were asked to return to campus in batches. All these students have been psychologically influenced by the epidemic to varying degrees. With the advent of the post-epidemic era, the building of a restorative environment has gradually attracted people's attention. The campus is the main place for students to live and study, so it is of great significance to understand the influence of campus environment on students' physical and psychological health. This research mainly aims to explore the following issues: 1) difference in psychological restoration between different types of campus environment; 2) influence of perceived preference on psychological restoration in outdoor campus environment; 3) influence of activities on psychological restoration in outdoor campus environment; 4) relationship between time of stay (time of stay on campus) and psychological restoration.

Methods  With college students as research object, this research takes the Northwest A & F University as an example and selects four different campus environments, namely blue space, green space, gray space and playground. The research adopts the field questionnaire survey method for experiment. The questionnaire consists of three parts. The first part is personal basic information, including gender, place of birth, time of stay and degree of concern about the epidemic. The second part is the special questionnaire survey, which requires the interviewees to firstly observe their campus environments, and then fill in such information as whether they like their campus environments, the reasons for their liking or disliking such environments, and the purpose of their coming to the interviewing site. The third part is the perceived restorative scale (PRS), which mainly evaluates the psychological restoration of the interviewees in their respective environments. The interviewees are required to conduct self-assessment on a 7-point Likert scale. The questionnaire was distributed twice between May and August 2020, concentrated in such intervals as 7:00−9:00, 12:00−14:00 and 17:00−19:00 every day, during which college students were not allowed out of the campus. In order to ensure the accuracy of experimental data collection, researchers distributed questionnaires simultaneously in seven sites within the research area. A total of 819 valid questionnaires were collected, and the valid data were numbered and recorded in Excel sheets. All statistical analyses were performed using SPSS 24 software.

Results  The results are as follows. 1) Blue space is considered the most restorative environment, followed by playground and green space, and gray space is the least restorative environment. 2) There exists a positive correlation between environmental preference and environmental restoration. The improvement of environmental preference characteristics (involving such landscape elements as fish, bird, tree and water) is beneficial to environmental restoration. 3) As to the behaviors of college students, the mixed behavior performs best in psychological restoration, followed by the dynamic behavior and the static behavior, while the passage behavior performs poorest. 4) The perceived environmental restoration ability of college students decreases with the time of stay, but students who stay for the longest time obtain the highest restoration score. The improvement of the compatibility dimension will be more conducive to environmental psychological restoration in the context of the epidemic.

Conclusion  Based on the above results, this research puts forward the following suggestions for the construction of restorative campus environment under the post-epidemic background. 1) For designers, blindly adding green space does not necessarily improve environmental restoration, while paying attention to the design of sports place or the synergistic effect of green space and sports can effectively improve environmental restoration. 2) Improving the characteristics of environmental preference is conducive to the recovery of environmental construction. The integration of landscape elements such as water, bird, tree and fish into the design and the optimization of environmental management can also contribute to the improvement of environmental recovery. 3) The design of college campus should best meet the needs of various activities. It is noteworthy that your willingness to enter an environment is a prerequisite for the environment to generate restorative experience for you. Therefore, promoting and encouraging healthy living habits is also an important factor in environmental restoration. 4) The more time you spend in an outdoor environment, the better restoration experience you will obtain from the environment. However, it is important to note that occasionally going out into a natural environment away from your familiar surroundings can also help relax you. In addition, adding environmental compatibility into campus landscape design can effectively improve the positive impact of environment on college students' psychology.