[论文解读] Urban greenery and mental wellbeing in adults: Cross-sectional mediation analyses on multiple pathways across different greenery measures

Ruoyu Wang, Marco Helbich+5 more|arXiv (Cornell University)|May 11, 2019

Urban Green Space and HealthEnvironmental Science参考文献 60被引用 19

一句话总结

本研究通过多种中介因素（包括身体活动、压力、空气质量、噪音和社会凝聚力）考察了中国广州城市绿化——通过街景影像（街景绿化）和卫星反演的NDVI——对成年人心理健康福祉的影响。街景绿化通过这些路径中介了其与福祉关联的62%，而NDVI仅中介了22%，表明不同绿化测量方式具有不同的作用机制。

ABSTRACT

Multiple mechanisms have been proposed to explain how greenery enhances their mental wellbeing. Mediation studies, however, focus on a limited number of mechanisms and rely on remotely sensed greenery measures, which do not accurately capture how neighborhood greenery is perceived on the ground. To examine: 1) how streetscape and remote sensing-based greenery affect people's mental wellbeing in Guangzhou, China; 2) whether and, if so, to what extent the associations are mediated by physical activity, stress, air quality and noise, and social cohesion; and 3) whether differences in the mediation across the streetscape greenery and NDVI exposure metrics occurred. Mental wellbeing was quantified by the WHO-5 wellbeing index. Greenery measures were extracted at the neighborhood level: 1) streetscape greenery from street view data via a convolutional neural network, and 2) the NDVI remote sensing images. Single and multiple mediation analyses with multilevel regressions were conducted. Streetscape and NDVI greenery were weakly and positively, but not significantly, correlated. Our regression results revealed that streetscape greenery and NDVI were, individually and jointly, positively associated with mental wellbeing. Significant partial mediators for the streetscape greenery were physical activity, stress, air quality and noise, and social cohesion; together, they explained 62% of the association. For NDVI, only physical activity and social cohesion were significant partial mediators, accounting for 22% of the association. Mental health and wellbeing and both streetscape and satellite-derived greenery seem to be both directly correlated and indirectly mediated. Our findings signify that both greenery measures capture different aspects of natural environments and may contribute to people's wellbeing by means of different mechanisms.

研究动机与目标

• 评估街景绿化和NDVI对广州市中国成年人心理健康福祉的影响。
• 识别并量化连接绿化与心理健康福祉的中介路径——包括身体活动、压力、空气质量、噪音和社会凝聚力。
• 比较街景绿化与NDVI在通过这些中介解释心理健康福祉方面的作用贡献。
• 评估不同绿化测量方式是否通过不同的心理和环境机制发挥作用。
• 通过整合地面观测与遥感数据，深化对城市绿化在心理健康中作用的理解。

提出的方法

• 利用谷歌街景的街景影像，通过卷积神经网络（CNN）处理，量化邻里尺度的街景绿化水平。
• 从卫星遥感数据中提取NDVI（归一化植被指数）作为植被覆盖的补充测量指标。
• 使用WHO-5福祉指数测量心理健康福祉，该量表为经过验证的自评工具。
• 采用多层次回归模型进行单重和多重中介分析，以考虑邻里层面的聚类效应。
• 检验两种绿化测量方式通过每个中介对福祉的间接效应，估计总间接效应和特定间接效应。
• 使用自助法置信区间评估模型拟合度和间接效应的显著性。

实验结果

研究问题

• RQ1 街景绿化和NDVI如何独立地与城市成年人的心理健康福祉相关？
• RQ2 绿化与心理健康福祉之间的关联在多大程度上由身体活动、压力、空气质量、噪音和社会凝聚力所中介？
• RQ3 街景绿化与NDVI的中介路径有何不同？
• RQ4 对于每种绿化测量方式，这些中介因素共同解释了绿化-福祉关系的多大比例？
• RQ5 街景绿化和NDVI是否捕捉了城市自然的不同方面，使其通过不同的机制影响福祉？

主要发现

• 街景绿化与NDVI呈弱正相关，但无显著相关性，表明二者衡量的是城市绿化中不同的方面。
• 街景绿化与更高的心理健康福祉显著相关，其中62%的这种关联通过身体活动、压力、空气质量、噪音和社会凝聚力得以中介。
• NDVI也与心理健康福祉呈正相关，但仅有22%的这种关联通过身体活动和社会凝聚力得以中介。
• 身体活动、压力、空气质量、噪音和社会凝聚力是街景绿化的重要部分中介因素，而NDVI仅在身体活动和社会凝聚力方面具有显著中介作用。
• 结果表明，街景绿化更能捕捉影响心理福祉的细微且感知相关的环境因素，并通过多条路径发挥作用。
• 两种绿化测量方式均通过直接和间接路径促进福祉，但街景绿化通过中介路径解释了关联的显著更大比例。