By Roger Harrabin
Hedges are often better than trees at soaking up air pollution among tall buildings, research has suggested.
A paper in the journal Atmospheric Environment says tall trees are good at absorbing pollution in more open areas. But hedges can trap toxins at exhaust pipe level, so reduce people's direct exposure to harmful pollutants.
Lead author Prof Prashant Kumar said councils should try to plant low hedges between pedestrians and the street if pavements are wide enough.
- Air pollution: 'Heart disease link found'
- Pollution particles 'get into brain'
- Ministers will not appeal pollution ruling
He and his partners in the EU and US are still researching the best pollution-busting plants, and the optimum height for the hedge.
But any gardener in a major city who has trimmed a privet hedge, for instance, will attest that it is full of dust and pollutants that the tight-knit foliage has filtered from the air.