Estimating the removal of atmospheric particulate pollution by the urban tree canopy of London, under current and future environments

Abstract Urban green space and particularly the tree canopy have been highlighted as offering a mitigation potential against atmospheric particulate pollution. In this paper current and future particulate (PM 10 ) deposition to the urban tree canopy of the Greater London Authority (GLA) was estimated. A modelling approach was used based on the Urban Forest Effects Model (UFORE) and a modified version. Here we give evidence showing that these deposition models can be adapted to run from annual mean meteorological and PM 10 concentration data, thus providing a methodology to examine future scenarios. Depending on the modelling approach, the urban canopy of the GLA is currently estimated to remove between 852 and 2121 tonnes of PM 10 annually; representing between 0.7% and 1.4% of PM 10 from the urban boundary layer. Estimates of PM 10 removal which take into account a planned increased in tree cover, from the current 20% to 30% of the GLA land area, suggest deposition of 1109–2379 tonnes (1.1–2.6% removal) by the year 2050. The evidence provided here suggests that the targeting of tree planting in the most polluted areas of the GLA and particularly the use of street trees which have the greatest exposure to PM 10 , would have the greatest benefit to future air quality. The increased deposition would be greatest if a larger proportion of coniferous to broadleaved trees were used at such sites.

[1]  K. Gaston,et al.  Urban Domestic Gardens (XIV): The Characteristics of Gardens in Five Cities , 2008, Environmental management.

[2]  Gail Taylor,et al.  Deposition velocities to Sorbus aria, Acer campestre, Populus deltoides X trichocarpa 'Beaupré', Pinus nigra and X Cupressocyparis leylandii for coarse, fine and ultra-fine particles in the urban environment. , 2005, Environmental pollution.

[3]  M. Perry,et al.  The generation of monthly gridded datasets for a range of climatic variables over the UK , 2005 .

[4]  Zaid Chalabi,et al.  An integrated tool to assess the role of new planting in PM10 capture and the human health benefits: a case study in London. , 2009, Environmental pollution.

[5]  Joe R. McBride,et al.  The urban forest in Beijing and its role in air pollution reduction , 2005 .

[6]  John N. Cape,et al.  Deposition of atmospheric pollutants on forests. , 1989 .

[7]  Roy M. Harrison,et al.  Dry deposition of ozone: some measurements ofdeposition velocity and of vertical profiles to 100 metres , 1985 .

[8]  R. Hill,et al.  The UK Land Cover Map 2000: Construction of a Parcel-Based Vector Map from Satellite Images , 2002 .

[9]  B. Hicks,et al.  A canopy stomatal resistance model for gaseous deposition to vegetated surfaces , 1987 .

[10]  Neil A Powe,et al.  Mortality and morbidity benefits of air pollution (SO2 and PM10) absorption attributable to woodland in Britain. , 2004, Journal of environmental management.

[11]  Martin L Williams,et al.  UK air quality in 2050—synergies with climate change policies , 2007 .

[12]  W. H. Smith.  Air pollution and forests. , 1981 .

[13]  Gail Taylor,et al.  THE CAPTURE OF PARTICULATE POLLUTION BY TREES AT FIVE CONTRASTING URBAN SITES , 2000 .

[14]  N. Hanley,et al.  Combating climate change: a role for UK forests. An assessment of the potential of the UK's trees and woodlands to mitigate and adapt to climate change. , 2009 .

[15]  D. Nowak,et al.  The Urban Forest Effects (UFORE) model: quantifying urban forest structure and functions , 2000 .

[16]  W. J. Bealey,et al.  Estimating the reduction of urban PM10 concentrations by trees within an environmental information system for planners. , 2007, Journal of environmental management.

[17]  J. C. Stevens,et al.  Air pollution removal by urban trees and shrubs in the United States , 2006 .

[18]  Atmospheric dry deposition to leaf surfaces at a rural site of India. , 2004, Chemosphere.

[19]  Gail Taylor,et al.  Effective Tree Species for Local Airquality Management , 2000, Arboriculture & Urban Forestry.

[20]  C. N. Hewitt,et al.  Development and application of an urban tree air quality score for photochemical pollution episodes using the Birmingham, United Kingdom, area as a case study. , 2005, Environmental science & technology.

[21]  E. Nemitz,et al.  Measuring Aerosol and Heavy Metal Deposition on Urban Woodland and Grass Using Inventories of 210Pb and Metal Concentrations in Soil , 2004 .

[22]  Gary M. Lovett,et al.  Atmospheric Deposition of Nutrients and Pollutants in North America: An Ecological Perspective , 1994 .

[23]  Gail Taylor,et al.  Particulate pollution capture by urban trees: effect of species and windspeed , 2000 .

[24]  W. Kuttler,et al.  On the reduction of urban particle concentration by vegetation : a review , 2008 .

[25]  G. Taylor,et al.  Capture of Particulate Pollution by Trees: A Comparison of Species Typical of Semi-Arid Areas (Ficus Nitida and Eucalyptus Globulus) with European and North American Species , 2004 .

[26]  E. Mcpherson,et al.  Chicago's urban forest ecosystem: Results of the Chicago Urban Forest Climate Project. (Includes executive summary). Forest Service general technical report (Final) , 1994 .

[27]  David J. Nowak,et al.  Air pollution removal by Chicago's urban forest , 1994 .