Page - 396 - in Biodiversity and Health in the Face of Climate Change

396 17.2.4 Greening Interventions There was strong evidence to support the greening of vacant lots (4/4 studies showed a significant intervention effect) and greening of urban streets (4/4 studies demon- strated a significant intervention effect), for environmental, physiological, psycho- logical and improved social environment outcomes (see Table  17.3). A decade-long study using a difference-in-difference design in the USA (Branas et  al. 2011) showed that greening of vacant urban lots (>725,000  m2) resulted in reductions in gun assaults (p  <  0.001), vandalism (p  <  0.001) and residents reporting less stress and more exercise (p  <  0.01). In an RCT, Garvin et  al. (2013) demon- strated a decrease in the number of total crimes and gun assaults, and increased safety around greened vacant lots compared with control lots (p  >  0.05). Anderson et  al. (2014) demonstrated significant biodiversity outcomes for a range of greening interventions in three deprived urban areas in South Africa. In a US-based study, South et  al. (2015) found that heart rate lowered significantly in  local residents living near greened compared to non-greened vacant lots (n  =  2 clusters of vacant lots) (p  <  0.001). Four (out of four) studies showed significant impacts on health and environmen- tal factors for interventions involving greening of urban streets. Ward Thompson et  al. (2014) found evidence to support the provision of so-called ‘DIY streets’ in urban areas in the UK.  Streets were made safer and more attractive (e.g. planting trees/plants), and traffic calming measures were added at nine different sites. Longitudinal data showed that participants perceived they were significantly more active post-intervention (p  =  0.04) than the comparison group, and there were sig- nificant improvements in perceptions of the environment. Joo and Kwon (2015) found that illegal dumping of household garbage occurred at 55.4% of greened sites (n  =  74) compared to 91.9% of sites without greenery (n  =  74) in South Korea. Strohbach et  al. (2013) showed a significant increase in bird species in a study investigating 12 community-driven greening projects involving tree plantings car- ried out in deprived areas compared to random urban sites without greening (p  =  0.049). Adverse outcomes from greening interventions were also reported by Jin et  al. (2014), who demonstrated that increased street tree canopy was positively associated with PM2.5 (particulate matter with aerodynamic diameters of 2.5  mm or less) concentrations owing to reduced air circulation. 17.2.5 Green Infrastructure Interventions There was promising evidence to support the provision of rain gardens (3/4 studies showed a significant positive effect) and strong evidence to support the provision of roof gardens (3/3 studies showed a significant positive effect) for managing the adverse impact of storm water. One study (1/1 study) demonstrated significant cool- ing effects for a roof garden in a suburban area (see Table  17.4). R. F. Hunter et al.