Hangzhou’s ambitious urban greening hinges upon activating neglected spaces such as land adjacent to and underneath freeways,along side railway lines(see Fig.3),along the banks of canals that transect the older urban core, and on former factory sites (Yang,Chang,Xu,Peng,&Ge,2008).The goals are to reduce heat island impacts,lessen storm-water and flooding though evaporation, intercept pollutants,and reduce wind speed(Chen,Bao,&Zhu, 2006).Preliminary research suggests urban greening is paying dividends, with temperature reductions of between 4◦ and 6◦ in some parts of the city Wenting,Yi,&Hengyu,2012).
However,although green space health benefits have not been studied extensively for Hangzhou, some new urban greening efforts may be problematic. Parks alongside freeways and rail corridors may expose users to air pollutants. A study by Byrne (2013) revealed under-provision of active recreation space in inner city districts in Hangzhou,with limited outdoor play spaces for children and teenagers. Existing inner city green space is often congested; when temperatures are high, it is often shoulder to shoulder in many of the city’s parks. Although many new residential communities incorporate green courtyard gardens, the overall amount of green space is very low. Some areas lack access to urban green space—especially older areas awaiting redevelopment and peripheral communities (SangLijieetal.,2013).