Effects of Urban Vegetation on Urban Air Quality

Vegetation has been well recognized for its ability in improving air quality and alleviating global warming. Tree planting has been used to mitigate urban heat island phenomena, sequester carbon dioxide, and help to trap air pollutants on leaves. Because some plant species emit biogenic volatile organic compounds (BVOCs), planting of some cultivars increase ozone and particulate matter ambient concentration and hence deteriorate air quality. Moreover, pollen grains and fungal spores from plants are health hazards for allergic or other sensitive members of the population. This paper reviews benefits and limited hazards of urban vegetation on air quality, highlighting useful computer simulations for predicting some of the interaction between urban forestry and the ambient atmosphere. To maximize the beneficial environmental effects of urban forestry, careful design, planning, and cost-benefit analysis would be required.