NCI-POST_0Earlier this month, parliamentarians and academics discussed the evidence on how urban open spaces can improve human well-being. Daija Angeli, NCI project officer, summarises what she learnt at the debate at the Houses of Parliament.

Living in cities may be exciting and culturally enriching, but it isn’t particularly good for your health. For example, 85% percent of children in Tower Hamlets live in homes that have levels of nitrogen dioxide in excess of air quality standards, and among the 1 in 6 adults and 1 in 10 children in the UK who suffer from depression and anxiety, the effects of urbanisation is a known contributor to illness. But how could greening our cities help tackle the growing number of mental and physical health issues of urban populations?

Parliamentarians and leading academics debated this question at the Houses of Parliament earlier this month at a round table discussion sponsored by the Natural Capital Initiative. The event followed up on last year’s POSTNOTE on “Urban Green Infrastructure” which summarises research evidence of the effectiveness of green infrastructure, and challenges to its implementation.

A range of speakers summarised the most important findings in their respective areas of expertise in four minutes and then discussed the research findings with the parliamentarians. Professor Rosie Hails (Centre for Ecology and Hydrology), Chair the Natural Capital Initiative’s Steering Group spoke about the challenges of integrating public health and environmental research. Prioritizing interventions based on the existing evidence is difficult, but the 25 year plan that is currently being developed by the Natural Capital Committee will set out measures to restore the aspects of green infrastructure that will provide the highest returns with regards to a broad range of social benefits.

What urban green infrastructure includes was one of the first questions parliamentarians asked. Turns out definitions vary in the research: while the POSTNote states that ’green infrastructure includes parks, playing fields, private gardens, allotments, green roofs and walls, and cemeteries’, Professor Jim Harris said that any unsealed surface can provide ecosystem services. With regards to our health, there is not much evidence about the influence of the quality of green space on our well-being, and an adequate design of green infrastructure will depends very much on the specific context and local peoples’ needs.

The positive impacts of green infrastructure have been studied when it comes to mental health. Dr Mathew White said that depression rates are 30% higher in areas with lower access to green space, and access to green space leads to immediate improvements in mental wellbeing. Mental health issues have a growing and costly impact in Britain, however, Professor Richard Mitchell pointed out, these issues are also linked to inequality; groups that are least well off in society are twice as likely to have poor access to green space in European urban areas. Access and use of green spaces can vary widely between socio-economic groups, but the major overall lifetime determinant is whether green infrastructure is used in childhood. Encouraging and enabling children to play in green spaces could thus pay off in the long term.

Dr Ian Mudway discussed the impacts of air pollution and how green infrastructure can help to mitigate the adverse effects in urban areas. Given that levels of pollution drop off with distance from the kerbside, clear health benefits occur from green corridors that separate pedestrians and cyclists from traffic. By using back street routes with lower levels of traffic pedestrians can reduce their exposure to air pollutants by 50%. Speakers proposed that a stronger separation of car and pedestrian traffic could help to reduce the negative effects of dieselisation. However, despite air pollution being second only to smoking as a cause of premature death, any restriction of car use is notoriously difficult for politicians to address as voters hold strong values in relation to car use.

At the same time, UK cities are likely to increase in density in the coming decades, particularly London. Green infrastructure should be seen as an integral part of a city rather than embellishing it. Peter Massini, urban greening team leader at the Greater London Authority highlighted that our planning efforts should focus on supporting the functions of the network, rather than the amenity value of individual green spaces. Tom Butterworth, Natural England’s senior adviser for local government, pointed out that considering the multiple benefits urban green infrastructure delivers, beyond health benefits which are currently very challenging to measure in monetary terms, might not only be useful to protect the network of urban green spaces but also might help to finance its maintenance (for example by water companies who benefit from an improved water quality).

Chi Onwurah MP who chaired the breakfast meeting concluded that the meeting had been one of the most informed debates on this topic she has heard in parliament. Given that a successful delivery of green infrastructure requires interdepartmental cooperation this is likely to remain a challenge for policy makers for some time.

Download POSTnote 448 Urban Green Infrastructure