Ranking current and prospective NO2pollution mitigation strategies: An environmental and economic modelling investigation in Oxford Street, London.
Air pollution continues to be a problem in the urban environment. A range of different pollutant mitigation strategies that promote dispersion and deposition exist, but there is little evidence with respect to their comparative performance from both an environmental and economic perspective. This paper focuses on examining different NO2mitigation strategies such as trees, buildings facades coated with photocatalytic paint and solid barriers in Oxford Street in London. The case study findings will support ranking the environmental and economic impacts of these different strategies to improve personal exposure conditions on the footpath and on the road in a real urban street canyon. CFD simulations of airflow and NO2dispersion in Oxford Street in London were undertaken using the OpenFOAM software platform with the k-ε model, taking into account local prevailing wind conditions. Trees are shown to be the most cost-effective strategy, with a small reduction in NO2concentrations of up to 0.7% on the road. However, solid barriers with and without the application of photocatalytic paint and an innovative material (20 times more expensive than trees) can improve air quality on the footpaths more substantially, up to 7.4%, yet this has a significant detrimental impact on NO2concentrations (≤23.8%) on the road. Photocatalytic paint on building surfaces presented a minimal environmental reductions (1.2%) and economic (>100 times more expensive than trees) mitigation strategy. The findings recognised the differences between footpath and road concentrations occurred and that a focused examination of three pollution hotspots can provide more cost effective pollution mitigation. This study considers how a number of pollutant mitigation measures can be applied in a single street canyon and demonstrates the strengths and weaknesses of these strategies from economic and environmental perspectives. Further research is required to extrapolate the findings presented here to different street geometries.
Department of Physics and Astronomy, University of Leicester, Leicester, UK.
A P R
APR
Jeanjean
Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Ireland; School of Environment, Natural Resources and Geography, Bangor University, UK.
J
J
Gallagher
Department of Chemistry, University of Leicester, Leicester, UK.
P S
PS
Monks
Department of Physics and Astronomy, University of Leicester, Leicester, UK. Electronic address: rl40@le.ac.uk.
R J
RJ
Leigh
D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis / Q000517:prevention & control* / Q000706:statistics & numerical data; D004777:Environment; D004784:Environmental Monitoring / Q000379:methods; D058735:Environmental Policy; D008131:London; D018803:Models, Economic; D008962:Models, Theoretical; D009585:Nitrogen Dioxide / Q000032:analysis*; D011446:Prospective Studies; D014197:Trees; D014919:Wind
D000393:Air Pollutants; D009585:Nitrogen Dioxide
Computational Fluid Dynamics; Deposition; Dispersion; Footpaths; Life cycle cost; OpenFOAM