College of Public Health and Human Sciences, Oregon State University, Corvallis, OR, USA.
J Expo Sci Environ Epidemiol. 2019 Jun;29(4):447-456. doi: 10.1038/s41370-018-0017-1. Epub 2018 Jan 19.
Urban green space, or natural environments, are associated with multiple physical and mental health outcomes. Several proposed pathways of action for these benefits (e.g., stress reduction and attention restoration) require visual perception of green space; however, existing green space exposure measures commonly used in epidemiological studies do not capture street-scale exposures. We downloaded 254 Google Street View (GSV) panorama images from Portland, Oregon and calculated percent of green in each image, called Green View Index (GVI). For these locations we also calculated satellite-based normalized difference vegetation index (NDVI), % tree cover, % green space, % street tree buffering, distance to parks, and several neighborhood socio-economic variables. Correlations between the GVI and other green space measures were low (-0.02 to 0.50), suggesting GSV-based measures captured unique information about green space exposures. We further developed a GVI:NDVI ratio, which was associated with the amount of vertical green space in an image. The GVI and GVI:NDVI ratio were weakly related to neighborhood socioeconomic status and are therefore less susceptible to confounding in health studies compared to other green space measures. GSV measures captured unique characteristics of the green space environment and offer a new approach to examine green space and health associations in epidemiological research.
城市绿地或自然环境与多种身心健康结果相关。这些益处的几种拟议作用途径（例如，减轻压力和恢复注意力）需要对绿地进行视觉感知；然而，现有的绿地暴露测量方法通常用于流行病学研究，但无法捕捉街道尺度的暴露情况。我们从俄勒冈州波特兰市下载了 254 张谷歌街景（GSV）全景图像，并计算了每张图像中的绿色百分比，称为绿色视图指数（GVI）。对于这些位置，我们还计算了基于卫星的归一化差异植被指数（NDVI）、树木覆盖率、绿地率、街道树木缓冲率、到公园的距离以及几个邻里社会经济变量。GVI 与其他绿地测量值之间的相关性较低（-0.02 至 0.50），这表明基于 GSV 的测量值捕捉到了有关绿地暴露情况的独特信息。我们进一步开发了 GVI：NDVI 比率，它与图像中垂直绿化空间的数量有关。GVI 和 GVI：NDVI 比率与邻里社会经济地位弱相关，因此与其他绿地测量值相比，在健康研究中受到混杂因素的影响较小。GSV 测量值捕捉了绿地环境的独特特征，并为在流行病学研究中检查绿地与健康的关联提供了一种新方法。
