Particulate matter that has been produced by traffic and which has become airborne can be slowed by hedges along the roads and precipitate onto the leaves of the hedgerow. Vegetation at ground level can also contribute to this, as precipitated particulate matter will settle and be less disturbed. However, this effect is doubted in the CROW-report.  CROW, 2011

Literature

• CROW (Centrum voor Regelgeving en Onderzoek in de Grond-, Water- en Wegenbouw en de Verkeerstechniek); Solve - luchtkwaliteit en verkeer; 2011