Background

A growing body of scientific literature indicates that urban green- and bluespace support mental health; however, little research has attempted to address the complexities in likely interrelations among the pathways through which benefits plausibly are realized.

Objectives

The present study examines how different plausible pathways between green/bluespace and mental health can work together. Both objective and perceived measures of green- and bluespace are used in these models.

Methods

We sampled 720 students from the city of Plovdiv, Bulgaria. Residential greenspace was measured in terms of the Normalized Difference Vegetation Index (NDVI), tree cover density, percentage of green areas, and Euclidean distance to the nearest green space. Bluespace was measured in terms of its presence in the neighborhood and the Euclidean distance to the nearest bluespace. Mental health was measured with the 12-item form of the General Health Questionnaire (GHQ-12). The following mediators were considered: perceived neighborhood green/bluespace, restorative quality of the neighborhood, social cohesion, physical activity, noise and air pollution, and environmental annoyance. Structural equation modelling techniques were used to analyze the data.

Results

Higher NDVI within a 300 m buffer around the residence was associated with better mental health through higher perceived greenspace; through higher perceived greenspace, leading to increased restorative quality, and subsequently to increased physical activity (i.e., serial mediation); through lower noise exposure, which in turn was associated with lower annoyance; and through higher perceived greenspace, which was associated with lower annoyance. Presence of bluespace within a 300 m buffer did not have a straightforward association with mental health owing to competitive indirect paths: one supporting mental health through higher perceived bluespace, restorative quality, and physical activity; and another engendering mental ill-health through higher noise exposure and annoyance.

Conclusions

We found evidence that having more greenspace near the residence supported mental health through several indirect pathways with serial components. Conversely, bluespace was not clearly associated with mental health.

中文翻译：

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多种途径将城市的绿色和蓝色空间与年轻人的心理健康联系起来

背景

越来越多的科学文献表明，城市的绿色和蓝色空间有助于心理健康。然而，很少有研究试图解决可能实现收益的途径之间可能存在的相互关系的复杂性。

目标

本研究探讨了绿色/蓝色空间与心理健康之间不同的合理途径如何协同工作。在这些模型中使用了绿色和蓝色空间的客观度量和可感知度量。

方法

我们从保加利亚的普罗夫迪夫市抽取了720名学生作为样本。住宅绿地的测量依据是归一化植被指数（NDVI），树木覆盖密度，绿地面积百分比以及到最近绿地的欧几里得距离。根据附近的存在以及到最近的蓝色空间的欧几里得距离来测量蓝色空间。心理健康状况通过《一般健康状况调查表》（GHQ-12）的12个项目进行衡量。考虑了以下调解人：邻里的绿色/蓝色空间，邻里的恢复质量，社会凝聚力，体育活动，噪声和空气污染以及环境烦恼。使用结构方程建模技术来分析数据。

结果

居住区周围300 m缓冲区内较高的NDVI与较高的绿地感带来了更好的心理健康；通过更高的感知绿地，从而提高恢复质量，并随后增加体力活动（即串行调解）；通过较低的噪声暴露，这又与较低的烦恼相关；并通过较高的感知绿色空间来实现，而绿色空间与较低的烦恼相关。由于竞争性的间接途径，在300 m缓冲区内存在蓝色空间与心理健康没有直接关联：一种通过更高的感知蓝色空间，恢复质量和身体活动来支持心理健康的方法；另一种则是通过增加噪音暴露和烦恼而引起精神疾病。

结论

我们发现有证据表明，居住地附近有更多的绿地，通过一些具有串联成分的间接途径来支持心理健康。相反，蓝色空间与心理健康没有明显联系。