Clean air gardens – could your front yard protect you from air pollution?

As part of the SRI’s role on the ERDF-funded business support programme, the ARENA project, we provided support to a company interested in exploring the potential for domestic garden design and certain planting schemes to help combat different air pollutants, and the influence on local air quality for households and local neighbourhoods. Air pollution is a major environmental health hazard, both for humans and biodiversity, and a leading environmental cause of human mortality and premature death worldwide (WHO, 2016). Reducing the source of emissions is of paramount importance for tackling this problem, but there are additional opportunities for remediating existing air pollution with nature-based solutions with several studies exploring the potential of plants to intercept air pollution. With a study by the Royal Horticultural Society revealing that in a ten year period (2005 – 2015) an additional three million front gardens were 100% paved over, it is clear that generating knowledge on the impact of domestic garden design on air quality is essential, so we can better understand the consequences of reducing plant cover in gardens and inform communities how to optimise their garden design for multifunctional benefits.

The starting point for our ARENA business support was a literature review, to gather data and synthesise existing knowledge from research on the role of plants and green infrastructure on air quality and air pollution remediation. The results from many studies indicated that the right plants in the right place could have a positive impact on air quality. Nevertheless, the findings were complex, with local conditions and certain plant species potentially creating trade-offs that could worsen air quality. At the time of the literature review, there were no published studies that had specifically examined the role of domestic gardens and their design on air quality, but we were able to outline some prototype designs, with a view to testing these to understand how they influence local air quality. The gap in knowledge represented an opportunity to start gathering data from existing gardens to generate some preliminary evidence on the potential impact of garden design on air quality.

ARENA ERDF project review as part of a business support programme.

With this potential research idea in mind, SRI Research Assistant, Dr Karina Corada Perez, a specialist in green infrastructure and air quality, identified a potential funding opportunity that could support a pilot study on domestic gardens and air pollution. RECLAIM (Reclaiming Forgotten Cities – Turning cities from vulnerable spaces to healthy places for people) is a £1.2m EPSRC-funded Network+ grant, led by the University of Surrey’s Global Centre for Clean Air Research (GCARE) in collaboration with the UK Centre for Ecology & Hydrology (UKCEH), and Universities of Bath, Bangor and Warwick. Building a community of practice, it funds small projects to better understand how green and blue infrastructure can reduce the effects of flooding, heat stress, air pollution, and other natural hazards. The SRI team behind the bid – Caroline Nash (PI), and Co-Investigators Karina Corada-Perez, Hebba Haddad and Stuart Connop – are now delighted to announce that our bid for the ‘Clean Air Gardens’ research project has been successful. We have been awarded funding by RECLAIM, to carry out a year-long study, building an evidence-base to understand the value of domestic gardens in tackling air quality problems in urban areas. As well as our air quality specialist, the multidisciplinary team bring expertise related to ecology, nature-based solutions and environmental psychology, so that research design and outcomes can deliver multifunctional environmental, ecological and social-justice benefits.

We are close to completing the initial scoping study, looking for suitable experimental sites through an air quality mapping exercise and using satellite imagery and Google’s Street View to identify stretches of road with similar air pollution conditions and certain garden designs. Once we have secured permissions from property owners and residents, we will begin to collect air pollution and air temperature data, making separate visits throughout the year, to capture information on the relationship between garden designs and air quality at different seasons throughout the year. A key output from our investigation will be a preliminary design guidance document, to empower individuals, particularly those vulnerable to poor air quality and/or extreme heat, to make informed decisions on how management of their garden or communal greenspaces can help improve their local environment. Lessons learned will be transferred to a wider audience, such as local authorities and social housing providers, to demonstrate the importance and potential value of providing suitably designed domestic gardens around dwellings, to benefit resident’s health and wellbeing. Watch this space for further updates as the project progresses!

This work has been supported by the UKRI-funded RECLAIM Network Plus grant (EP/W034034/1).

By Caroline Nash