A guide has been published offering advice on which plants are most effective at combatting harmful air pollutants.
The ‘Phyto-sensor’ toolkit was developed by the Citizen Sense research group led by Professor Jennifer Gabrys an academic at Goldsmiths, University of London.
The toolkit includes instructions for identifying the best locations for ‘air quality gardens’, as well as different planting strategies and maintenance techniques.
The toolkit was tested and refined through a public workshop and walk held at the Museum of London in March to investigate ways vegetation can improve air quality.
The Museum of London partnered with Citizen Sense to develop the toolkit, and a demonstrator garden of air quality plants was on display during the workshop.
Plants in the toolkit were selected for their suitability to reduce or ‘bioindicate’ different types of air pollution in the urban environment. Bioindication refers to plants’ changes in appearance when certain pollutants are present.
Professor Gabrys said: “Recent news coverage has highlighted the serious issues this country faces both in pollution levels in towns and cities. This report provides timely advice for people who want to know how they can use vegetation to both mitigate and monitor pollutant levels. This is a citizen’s toolkit for planting air quality gardens.”
A number of plants highlighted by the report are claimed to be effective in combatting particulate matter, including the wallflower, or Erysimum, which combats PM2.5 and PM10 – air pollutants with different-sized particles comprising dust, sand and soot.
The common ivy plant also traps particulates, and is described as ‘ideal for air purification’ due to the extensive surface area of its leaves, the guide claims.
Some of the plants are also thought to combat nitrogen dioxide, including Alchemilla mollis or ‘Lady’s Mantle’.
Among the best bioindicating plants, the guide suggests, are Aster, which reveals high levels of ozone by yellowing leaves, and Osmanthus, which displays ‘chronic’ leaf damage when exposed to sulphur dioxide. Some of these plants also take up heavy metals and phyto-remediate soils.
Professor Gabrys added: “While reducing emissions at source is the best way to address air pollution, plants can play an important role in mitigating against it. This toolkit is designed to equip people with the knowledge and inspiration to plant gardens that can improve air quality and enhance the urban realm. The research builds on citizen monitoring of air quality in Deptford and New Cross, which found that good urban design can significantly improve air quality levels.”
The report’s other recommendations include planting particular trees to improve local air quality, and the installation of green walls and screens as barriers to busy roads. Examples of successful community projects that have used these planting scenarios are included in the toolkit.