Hedges can cut air pollution by half, scientists have found after studying particulate levels on either side of a bush near a children's playground.
In what is believed to be the first study of its kind, researchers from the University of Surrey measured traffic pollutants with the use of emerging pollution sensing technology behind and in front of a hedge that shielded a children’s park in Guildford.
On the other side of the hedge, which they monitored for five months, was a road, with cars producing particulate pollution, which is tiny particles of soot and other matter in the air.
This can cause illnesses including asthma when children are exposed to it for a long period of time and in large quantities.
Experts reported reductions of more than 50 per cent of the particulate matter after the hedge was in full greenery in late April.
Professor Prashant Kumar, Director of Surrey's Global Centre for Clean Air Research and the corresponding author of the study, said: “We believe our study is the first to look at how a hedge affects the pollution from traffic – assessing the influence of the vegetation lifecycle, wind direction and other variables.
"The reduction in pollution after the green-up stage gives valuable information regarding where to install green infrastructure across our communities."
Professor Kumar called for cities and towns to put up hedges around parks, schools and paths to absorb pollution.
He said: "This study has not only produced unique evidence and support for our advocacy to install hedges and other forms of green infrastructure (where appropriate) along busy roadsides to protect schools, playgrounds and pedestrians/cyclists from air pollution exposure; it has also provided a clear indication that evergreen species should be favoured for barriers against air pollution to exploit their year-round performance."
The study, published in Sustainable Cities & Society, recommended using coniferous hedges instead of deciduous, as the most significant air pollution reductions were in spring, when the hedge was in full leaf.