This study employed a cross-sectional pilot survey design to examine associations between green space accessibility, usage patterns, activity types, and perceived mental health and social outcomes among university students in Kobe City, Japan. Cross-sectional designs are widely used in environmental health research to explore relationships between exposures and outcomes at a specific point in time, particularly in exploratory and hypothesis-generating studies ([25]; [36]). Kobe City, located in Hyogo Prefecture, provides a distinctive urban context characterized by a narrow coastal plain bordered by mountainous terrain, resulting in uneven spatial distribution and accessibility of green spaces. Such geographic heterogeneity offers a valuable setting to investigate how environmental accessibility and urban form shape green space use and well-being ([20]).

The target population comprised undergraduate and graduate students (aged ≥ 18 years) enrolled at KCUFS. University students were selected as a focal group due to their heightened vulnerability to mental health challenges linked to academic stress, social transitions, and urban living ([3]; [38]). A non-probability convenience sampling approach was adopted, with participants recruited from classes taught by the lead author. Data collection was conducted in July 2024, yielding 128 valid responses. The sample size is appropriate for a pilot study aimed at testing survey instruments and identifying preliminary associations. Prior methodological guidance suggests that samples of 100 - 150 are sufficient for pilot studies assessing feasibility and instrument reliability ([7]; [14]). Additionally, for chi-square analyses, a sample size exceeding 100 is generally adequate to detect medium effect sizes ([8]).

Data were collected using structured, self-administered online questionnaire developed using Google Forms. To ensure inclusivity and reduce language bias, the survey was administered in both English and Japanese, reflecting the diverse student population at KCUFS. In this study, perceived inclusivity refers to participants’ perception that urban green spaces are welcoming, accessible, comfortable, and usable by people from diverse backgrounds, regardless of age, gender, nationality, cultural background, or physical ability. It also reflects whether respondents perceived green spaces as places where everyone feels safe, accepted, and able to participate in recreational or social activities. Inclusivity was assessed using participants’ self-reported perceptions collected through the questionnaire. The questionnaire was initially developed in English and subsequently translated into Japanese by bilingual researchers. The translated version was reviewed by bilingual researchers to ensure conceptual equivalence, consistency of meaning, and cultural appropriateness across both language versions before survey administration.

The questionnaire was designed based on established frameworks in environmental psychology and public health research ([13]; [4]) and comprised six sections:

Demographics: age, gender, nationality, and duration of residence in Kobe.Green space use and perception: frequency of visits, accessibility, and perceived quality.Mental health and well-being: emotional responses, stress reduction, and perceived benefits.Social interaction: frequency and types of social engagement in green spaces.Green space management and policy: perceptions of safety, inclusivity, and adequacy.SDG relevance: perceived contributions to sustainability and well-being.

The principal study constructs were operationalized using self-reported survey measures. Perceived accessibility was assessed through a single-item question asking respondents to rate how accessible urban green spaces were to them, with response categories ranging from “Not accessible” to “Very accessible.” Inclusivity was measured by participants’ agreement with the statement that green spaces in Kobe City were inclusive and welcoming to diverse users, using a five-point Likert scale from “Strongly disagree” to “Strongly agree.” Perceived mental health benefits were assessed through respondents’ agreement with the statement that access to green spaces positively contributed to their mental well-being, also using a five-point Likert scale. Social interaction was evaluated through questions regarding the frequency of interactions occurring in green spaces and the primary groups with whom respondents interacted (e.g., friends, family, neighbors, or strangers).

The survey included Likert-scale items, binary responses, and multiple-choice questions, along with one open-ended question to capture qualitative insights. Since the principal outcome measures in this exploratory pilot study were assessed using single-item indicators rather than multi-item scales, internal consistency reliability measures such as Cronbach’s alpha were not applicable. The pilot phase enabled refinement of question clarity, structure, and respondent engagement.

Data were analyzed using IBM SPSS Statistics (version 28). Descriptive statistics (means, standard deviations, frequencies, and percentages) were used to summarize participant characteristics and usage patterns. To examine relationships between categorical variables, Pearson’s chi-square (χ²) test of independence was applied. This method is commonly used in public health and social science research to assess associations between categorical variables ([31]). Key variables examined included green space accessibility, visit frequency, activity type, perceived mental health outcomes, and social interaction. Statistical significance was set atp < 0.05. Given the exploratory nature and limited sample size of the pilot study, multivariate analyses (e.g., regression or structural equation modeling) were not conducted. However, the findings identify key variables such as activity type, inclusivity, and emotional responses that warrant inclusion in future multivariate analyses in larger, more representative samples ([4]).

The study adhered to established ethical standards for social science research ([16]). Participation was voluntary, and informed consent was obtained digitally prior to survey completion. Participants were informed of the study’s purpose, their right to withdraw at any time, and the confidentiality of their responses. All data were anonymized, with no personally identifiable information collected. Data were securely stored and accessible only to the research team, ensuring compliance with data protection and ethical research practices.

A total of 128 students from KCUFS participated in the survey. The mean age of respondents was 19.60 years (SD ± 1.47), reflecting a young adult population typical of undergraduate students. Notably, 50% of participants had resided in Kobe City for less than one year, indicating a high proportion of newcomers to the city, likely due to their recent enrollment. This demographic feature is particularly relevant, as prior studies suggest that newcomers often rely on public spaces as avenues for social integration and place attachment ([35]). Table 1 shows the general characteristics of the participants in the survey.

Table 1.General characteristics of the study subjects (N = 128).

Regarding usage, the majority of respondents (39.8%) reported visiting green spaces rarely, while only a small segment reported frequent use. Parks emerged as the most preferred type of green space (68.0%), followed by smaller green patches and community gardens. The most common activities were walking (45.3%) and relaxing (29.7%), while jogging, photography, and socializing were less frequent but notable. This aligns with global findings that walking and passive relaxation are dominant activities in urban greenery ([34]). Importantly, perceptions of green spaces were largely positive: 47.7% agreed and 42.9% strongly agreed that these spaces contribute to mental health benefits. Suggestions for improvement centered on infrastructure enhancements, such as benches, shaded areas, and restrooms (49.2%). This demand mirrors prior evidence that supportive amenities significantly influence both usage patterns and perceived quality of urban parks ([22]).

Pearson’s chi-square test revealed a statistically significant association between perceived accessibility and frequency of visits (χ² = 29.290, df = 16, p = 0.022) as shown in Table 2. Students who rated green spaces as “very accessible” were more likely to visit them regularly. This finding is consistent with established evidence that accessibility is one of the most critical determinants of green space utilization ([32]; [20]). For students who often balance academic schedules with limited free time, ease of access appears to be a crucial facilitator of engagement with green spaces.

Table 2. Relationship between perceived green space accessibility and frequency of visit.

A statistically significant association was observed between perceived accessibility and inclusivity of green spaces, indicating that respondents who considered green spaces easier to access also tended to perceive them as more welcoming and suitable for people from diverse backgrounds. (χ² = 33.936, df = 12, p < 0.001) as shown in Table 3. Students who rated green spaces as “accessible” or “very accessible” tended to perceive them as more inclusive, whereas those who viewed them as “not accessible” or “somewhat accessible” reported lower levels of inclusivity. This finding suggests that higher perceived accessibility was associated with greater perceptions of inclusivity and belonging within green spaces.

Table 3. Relationship between accessibility and inclusivity of green spaces.

The type of activity performed in green spaces was significantly associated with mental health outcomes (χ² = 35.867, df = 18, p = 0.007) as shown in Table 4. Passive activities such as relaxing and meditating were more commonly associated with reports of calmness and reduced anxiety, whereas active engagements such as jogging and walking were more commonly associated with increased energy and reduced stress. This dual effect reflects the restorative and activating pathways of nature engagement discussed in environmental psychology literature ([24]; [30]). Furthermore, the type of green space visited was significantly associated with emotional responses (χ² = 36.983, df = 20, p = 0.012) as shown in Table 5. Parks, the most frequently visited spaces, were strongly associated with relaxation (62.9%), stress reduction (81.0%), and happiness (100%). In contrast, community gardens and smaller patches elicited weaker impacts, potentially due to limited size, facilities, or maintenance. This emphasizes the role of design and quality in shaping psychosocial benefits, echoing [39] on green space quality in urban Japan.

Table 4.Relationship between green space activities and perceived mental health benefits.

Table 5.Relationship between type of green space visited and emotional impact.

Interestingly, no significant association was found between visit frequency and mental health benefits (χ² = 9.564, df = 12, p = 0.654) as shown in Table 6. These findings indicate that visit frequency was not significantly associated with perceived mental health benefits in this sample. This contrasts with assumptions that more frequent exposure necessarily leads to greater benefits. Instead, quality and type of interaction appear more influential, a finding consistent with [13] and [9]. For urban planning, this indicates that simply increasing visitation may not be sufficient; enhancing the experiential quality of green spaces is equally critical. Similarly, accessibility was not significantly related to perceptions of community cohesion (χ² = 15.322, df = 16,p = 0.501) as shown in Table 7. Although accessible spaces encourage visits, their social role may depend more on intentional design features (e.g., gathering spaces, programming) rather than accessibility alone.

Table 6.Relationship between green space visit and perceived mental health benefits.

Table 7.Relationship between accessibility of green spaces and perceived role in promoting community interaction.

The cluster analysis was conducted as an exploratory technique to investigate whether distinct patterns of green space engagement could be identified among participants. Although the resulting three-cluster solution demonstrated poor silhouette quality and should therefore be interpreted cautiously, the analysis was retained to provide preliminary insights into potential behavioral groupings that may warrant further investigation in larger samples.A two-step cluster analysis was conducted using visit frequency, type of activity, community interaction, and emotional responses as shown in Figure 2. While a three-cluster solution was generated, the silhouette coefficient indicated poor model fit, suggesting overlapping patterns of behavior and weak subgroup differentiation. This limitation reflects the complexity of human-nature interactions, where individuals often engage in multiple overlapping ways (e.g., using parks both for relaxation and socializing). Larger and more diverse samples are needed to detect meaningful user typologies.

Figure 2.Distribution of participants across user profile clusters.

A chi-square test found no significant association between residency duration and perceived mental health benefits of green space access (χ² = 5.61, df = 9, p = 0.778) as shown in Table 8. Students reported similarly positive perceptions of mental health benefits regardless of how long they had lived in Kobe City. More than 90% of respondents across residency-duration categories either agreed or strongly agreed that green space access contributes positively to mental well-being. These findings suggest that the psychological benefits of urban green spaces are shared by both newcomers and long-term residents.

Table 8.Relationship between perceived mental health benefits and residency duration.

Several limitations should be acknowledged. First, the use of convenience sampling limits the generalizability of the findings, as the sample may not be representative of the broader student population or other urban residents. Second, reliance on self-reported measures introduces potential recall and social desirability biases, which may affect the accuracy of reported behaviors and perceptions. Third, the cross-sectional design restricts causal inference, making it difficult to determine whether green space use contributes to improved mental health or whether individuals with better mental health are more likely to engage with green spaces ([36]). Given the exploratory nature of this pilot study, the findings should be interpreted as preliminary evidence of associations rather than confirmation of causal relationships. These limitations point to several directions for future research. Studies with larger and more diverse samples are needed to improve representativeness and allow for subgroup analysis. Longitudinal designs would enable examination of temporal relationships and causal pathways between green space exposure and mental health outcomes. In addition, mixed-method approaches, incorporating qualitative methods such as interviews or participatory mapping, could provide deeper insights into how individuals experience and engage with green spaces in everyday contexts.

An additional limitation relates to the chi-square analyses. Several contingency tables contained cells with expected frequencies below five, indicating partial violation of the assumptions of Pearson’s chi-square test. Consequently, some associations should be interpreted with caution. Future studies should employ larger sample sizes and consider collapsing sparse categories or applying exact statistical methods where appropriate.

Future research would also benefit from integrating objective measures of exposure and health outcomes. The use of spatial data, such as GIS-based accessibility and proximity indicators, can provide more precise assessments of environmental exposure, while physiological measures (e.g., cortisol levels, heart rate variability) can complement self-reported well-being and strengthen the robustness of findings ([10]; [23]). Such approaches would enable a more comprehensive understanding of the mechanisms linking urban green spaces, mental health, and social interaction.