It is estimated that by 2050, around four-million deaths per year will be attributable to outdoor air pollution. The MAGIC project aims to develop tools to support the design of greener cities, with a focus on naturally ventilated buildings and the connection between indoor and outdoor air quality. Huw’s focus on the project has been on developing a computational fluid dynamics model, Fluidity, for the simulation of air flow and pollution dispersion in urban areas.
Traffic emissions contribute significantly to pedestrian exposure of ultrafine particles and NO2 in urban areas, with the daily commute contributing a disproportionately high fraction to overall daily exposure. Measurement studies have shown that concentrations at the roadside are highly variable in space and time. However estimates of exposure tend to be based on longer time averages, often hourly or daily, and based on smooth concentration fields derived from Land Use Regression or Gaussian plume models, or on measurements at fixed sites. Further, pollution hotspots such as at busy junctions remains a significant problem, the impact of which is difficult to evaluate. A novel two fluid approach coupled with an instantaneous emissions model has been developed in an attempt to resolve this high variability. An exposure analysis was performed on a typical intersection to demonstrate the potential impact of this variability and highlight the importance of considering emission spikes from vehicles during acceleration. This work led to the implementation of a field study aimed at adjusting the traffic light signal timings at a junction in London with the aim of reducing pedestrian exposure while crossing. The analysis of the results is in progress however the early results indicate that adjusting the signal timings can have a significant impact on average concentrations seen at the roadside.

Huw Woodward is a Research Associate at the Centre for Environmental Policy at Imperial College London focusing on pollution dispersion modelling as part of the MAGIC project. The MAGIC project is a collaboration between Imperial College, Cambridge University and the University of Surrey, with the aim of improving our understanding of the connection between indoor and outdoor air quality. Huw’s focus within the project is on microscale dispersion modelling, using computational fluid dynamics to investigate the effect of features such as traffic induced turbulence, trees and roof geometry on the dispersion of pollutants within urban areas. Huw also works within the Integrated Assessment Unit for DEFRA using the UK Integrated Assessment Model (UKIAM) to estimate future projections of UK air quality and leads the work on ecosystem health.

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