Effective Tree Species for Local Airquality Management

The beneficial effect that trees have on air quality is often stated in arboricultural literature but has rarely been researched. The presented study aims to identify trees from 5 contrasting species that maximize the benefit to local air quality. Results show that all trees examined captured large quantities of airborne particulates, from the health-damaging size fractions (particle diameters of 10 to 2.5 |im, 2.5 to 1 |Xm, and <1 |am). Coniferous species were found to capture more particles than did broad-leaves, with pines (Pinus spp.) capturing significantly more material than cypresses (Cupresses spp.). Of the broad-leaved species, whitebeam (Sorbus aria) captured the most and poplar (Populus spp.) the least weight of particles. Trees situated close to a busy road captured significantly more material from the largest particle size fraction than those situated at a rural, background site. There was very little variation between the 2 sites in the weight of particulates from the 2 smallest particle size fractions (i.e., the fractions that are potentially the most damaging to human health).