AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Passive Control Systems for Improving Air Quality in Urban Street Canyons: The Origins, Current State of Art and Next Steps
JOHN GALLAGHER, Brian Broderick, Prashant Kumar, Aonghus McNabola, Francesco Pilla, Trinity College Dublin
Abstract Number: 197 Working Group: Passive Mitigation Strategies to Reduce Exposure to Near-Road Air Pollution
Abstract Strategies to improve urban air quality have primarily focused on reducing emissions through campaigning for green alternative modes of transport and improving the efficiency. Despite their associated improvements for air quality, our cities continue to represent some of the most polluted zones on the planet. In the last decade, solid and porous barriers have received growing attention from the research community as the presented solutions can potentially mitigate this air pollution. This passive solution considered methods of improving air quality by influencing air flow patterns and enhancing the dispersion and deposition of gaseous and particulate pollutants.
Previous research has demonstrated how street canyon geometry and local meteorological conditions are the dominant characteristics that affect air quality in the urban environment. Through measurement, modelling and wind-tunnel experimentation, a deeper understanding of how passive control systems in urban street canyons can work in harmony with local conditions to maximise pollutant dispersion and deposition. Solid barriers, including low boundary walls and parked cars, have been shown to improve air quality on the windward footpath and trap pollutants on the leeward footpath depending on the size, orientation and spacing of these control measures. Alternatively, green infrastructure, such as trees, hedges, green roofs or green walls, delivers improved air quality under the same varying conditions, but has the benefit of achieving both dispersion and deposition of pollutants.
The next steps in this field suggests more detailed analysis of real-world condition, as understanding the performance of passive control systems in different climatic conditions is required. In addition, improving the ability of numerical modelling and scaled wind-tunnel experiments to account for vehicular turbulence effects, fluctuating wind conditions and ensure that passive barriers abate as opposed to trap pollutants. Therefore, more real-word measurement studies are necessary to enhance current findings and to allow for the accurate extrapolation of findings.