What we know
Green space has been shown to improve air quality through the absorption of pollution by vegetation, promote informal and formal physical activity with a consequent positive effect on physical health, and help reduce stress levels and promote mental health. These relationships between ecosystems services and health benefits can be categorised as:
- Ecosystem services and physical health: there is a growing body of evidence indicating that the ecosystem services provided by high quality green space are a significant influence on physical health. Such ecosystem services are particularly beneficial when they are easily accessible and exist in proximity to residential areas. For example, in a significant study of 6,919 people across eight European countries varying in wealth, culture and history, it was concluded that the probability of being physically active may be as much as three times greater in residential environments possessing high levels of access to green space, with the likelihood of being overweight up to 40% less (Ellaway et al., 2005). Other studies substantiate these findings by demonstrating that access to green space increases positive assessment of their neighbourhood by residents and encourages use of local green space for physical activity (Björk et al., 2008; Lestan et al., 2014). Furthermore, recent research suggests that encouraging use of green space to promote better physical health can be advanced through careful planning of linear parks that can be accessed and used by people to replace motorised transport with cycling and walking in their daily commutes (Dallat et al., 2014). Such research indicates that significant savings can be made to the costs of public health provision through the conscious design of places to supply greater opportunities for physical activity. Indeed, by employing UK statistics, Mourato et al, (2010) calculated that a benefit from increased accessible green space provision of almost £2 billion would have accrued to the UK government in 2001 through savings in the health costs incurred of treating just three physical conditions (coronary heart disease, colo-rectal cancer and stroke) and reductions in morbidity from mental health.
- Ecosystem services and mental health and well-being: greenspaces have been shown to deliver measurable mental health benefits and contribute to general psychological well-being (Grahn and Stigsdotter, 2003; Nielsen and Hansen, 2007). Such services are provided through supplying ‘restorative environments’ (Kaplan and Kaplan, 1989), which perform a role in reducing stress from the complex demands of everyday life and helping people cope with depression, bereavement and mental fatigue (CABE, 2005). These services may be particularly important within an urban context where exposure to stresses may be more acutely perceived (Beyer et al., 2014; van den Berg et al., 2010). Epidemiological studies have identified positive effects of greenspaces on the self-reported physical and mental health of residents (e.g. de Vries et al., 2003; Guite et al., 2006; Maas et al., 2006; van den Berg et al., 2010) and longevity (e.g. Takano et al., 2002b), with Guite et al. (2006), identifying an association between the presence of ‘escape facilities’ such as greenspace and mental well-being across a range of domains.
- Ecosystem services and mitigating other forms of environmental risk to health: green spaces and their associated vegetation can positively influence health through contributing to improved air and water quality. Vegetation can help remove airborne pollutants whether in particulate or gaseous form. This is an especially pertinent issue in urban environments where traffic related pollutants can prove detrimental to physical health and mental well-being. For example, broad leaved woodlands can reduce ambient air pollution by 17% (Dunnett et al., 2002). Carefully designed green spaces can also assist in water filtration which facilitates biodiversity, thereby enhancing well-being by assisting in the provision of greater opportunities for contact with nature (Everard et al., 2012). Furthermore, green spaces perform valuable ecosystems services that alleviate environmental risks to human health by mitigating the negative effects of climate change via urban cooling (Gill et al., 2009) and capturing surface run-off so as to reduce the severity of flood events during heavy downpours or periods of prolonged precipitation (Lennon et al., 2014).
Underlying the health-related ecosystem services provided by ease of access to green spaces is the importance of equity. Such issues can be categorised into equity across socio-economic groups and equity across age cohorts.
- Health equity across socio-economic groups: lower socio-economic groups have traditionally suffered from poorer access to high quality green space provision. This inequitable socio-spatial configuration has been linked to inferior health among such groups (Northridge and Freeman, 2011). There is strong evidence to indicate that people with ease of access of green spaces have lower levels of health inequality related to income deprivation (Mitchell and Popham, 2008). This suggests that ensuring all residential environments are rich in high quality green space provision is a means to reduce socioeconomic health inequalities. Such spaces can include large public parks, smaller neighbourhood green spaces and greenways (cycle and walking routes) (Blackman, 2013).
- Health equity across age groups: concern regarding health equity also centres on vulnerable age cohorts, primarily the young and the elderly. Ease of access and use of green space has been shown to positively contribute to cognitive, social and physical development in children (Strife and Downey, 2009). Indeed, there is now an increasing volume of research indicating that children regularly exposed to nature enjoy improved cognitive functioning (including better concentration, longer attention capacities and higher academic performance), better motor coordination, reduced levels of stress and more developed social skills both in their interactions with adults and other children (Christian et al., 2015; Fjørtoft, 2001; Kahn and Kellert, 2002; Taylor et al., 2001; Wells and Evans, 2003). Accessible green spaces have also been shown to contribute to the physical health and psychological well-being of elderly people. For example, a large scale study of residential districts in Tokyo that accounted for socioeconomic status, age, gender and marital status found that accessible green space was an important factor contributing to longer life spans (Takano et al., 2002a). Of pertinence to an Irish cultural, climatic and genetic context is a study of 1,010 men aged 66 and over conducted in Wales, where it was concluded that elderly men living in neighbourhoods with more green space had higher levels of participation in regular physical activity (Gong et al., 2014). Similarly, in a cross-sectional study of older people in Britain, it was found that proximity to neighbourhood open space closely correlated with life satisfaction and psychological well-being (Sugiyama et al., 2009).