Green Spaces as an Indicator of Urban Health: Evaluating Its Changes in 28 Mega-Cities

Conghong Huang,Hui Lu,Le Yu,Jun Yang,Huabing Huang

doi:10.3390/rs9121266

Abstract

Urban green spaces can yield considerable health benefits to urban residents. Assessing these health benefits is a key step for managing urban green spaces for human health and wellbeing in cities. In this study, we assessed the change of health benefits generated by urban green spaces in 28 megacities worldwide between 2005 and 2015 by using availability and accessibility as proxy indicators. We first mapped land covers of 28 megacities using 10,823 scenes of Landsat images and a random forest classifier running on Google Earth Engine. We then calculated the availability and accessibility of urban green spaces using the land cover maps and gridded population data. The results showed that the mean availability of urban green spaces in these megacities increased from 27.63% in 2005 to 31.74% in 2015. The mean accessibility of urban green spaces increased from 65.76% in 2005 to 72.86% in 2015. The increased availability and accessibility of urban green spaces in megacities have brought more health benefits to their residents.

Highlights

Urban green spaces are important for urban residents’ health [1,2]
Due to the large population of megacities, the health benefits generated from urban green spaces are especially valuable
We developed a method based on remote sensing data to conduct a quick assessment of the potential supply of health benefits by urban green spaces in 28 megacities

Summary

Introduction

Urban green spaces are important for urban residents’ health [1,2]. Green spaces can contribute to public health through improving air quality, alleviating the urban heat island effect, lowering the level of noise [1,9]. They can enhance physical activity [10], reduce stress, improve social cohesion [11], and enhance functioning of immune systems [12]. Maintaining urban green spaces and enhancing their health benefits is an important component of urban health management

Results

Discussion

Conclusion