People living in polluted urban areas are far less likely to be admitted to hospital with asthma if they live in neighbourhoods with lots of trees, a new University of Exeter study has found. The research, published in the journal Environment International in December, suggests that more trees in your street could help reduce the effects of air pollution from cars.
The study examined looked at more than 650,000 serious asthma attacks over a 15-year period. In the most polluted urban areas, trees had a particularly strong association with fewer emergency asthma cases. In a typical urban area with a significant level of pollution, an extra 300 trees per square kilometre was connected to 50 fewer cases of emergency asthma per 100,000 residents.
Dr Ian Alcock, head researcher of the study, said the results build on previous knowledge that greenery has positive effects for respiratory conditions. “We know that trees remove the air pollutants which can bring on asthma attacks, but in some situations they can also cause localised build-ups of particulates by preventing their dispersion by wind”, he said. “We found [that] urban vegetation appears to do significantly more good than harm.”
In suggesting that tree-planting could play a role in reducing the effects of air pollution from cars, the study’s findings could influence city planning and public health policies around the world.