Wind tunnel tests are key to healthier towns
New tests involving a large wind tunnel could prove the key to improving air quality in our towns and cities. The tests are designed to improve understanding of how pollution and heat behave at street level so that more effective ventilation methods can be developed.The research will be carried out by scientists at the University of Reading in collaboration with EnFlo, based at the University of Surrey, with funding from the Engineering and Physical Sciences Research Council (EPSRC).
In towns and cities, pollution and heat released below building height (eg from cars and buildings) can be trapped at street level until ventilated to the air above. This can cause pollution "hotspots" which affect sufferers from respiratory diseases such as asthma; it can also contribute to an uncomfortably warm urban climate.
Typical pollution found at street level in urban areas includes fine particulates, carbon monoxide and ozone, which can affect the lungs, and carbon dioxide and larger particulates, which can contribute to a local "greenhouse" effect and raise urban temperatures.Ventilation process
The new research will focus on the ventilation process. This process depends on street layout, wind speed and other factors, and understanding it is vital to taking effective action to improve urban climate and air quality. The project will centre on wind tunnel tests that simulate airflow in urban areas. Cube and bar shapes representing a variety of urban settings will be placed in a wind tunnel and covered in naphthalene (an aromatic hydrocarbon used in mothballs), which is carried by airflow in a similar way to heat and pollution. By measuring the net loss of naphthalene after air has flowed over it, the rate of ventilation for the airflow and urban layout under examination can be calculated.
Interpretation of the results, which will require expertise in fluid dynamics, turbulence, heat transfer and meteorology, will enable the impact of different factors on ventilation to be assessed. An innovative feature of the research will involve the use of sensors to detect naphthalene concentrations. Deploying the sensors successfully will require trial and error, but will ultimately enable the extent and duration of "hotspots" to be determined.
The project team has already found that ventilation depends on street width, building height and the precise location of the pollution or heat source. Dr Janet Barlow, who is leading the team at the University of Reading's Department of Meteorology, says: "Better understanding of heat and pollution ventilation rates will help inform the decision-making of architects and town planners. This should help to promote more sustainable, more comfortable and healthier urban environments".Funding from EPSRC
The 22-month research initiative, Quantifying Turbulent Ventilation of Heat and Pollution from Urban Areas, will receive funding from EPSRC of nearly £98,000. EnFlo is the Environmental Flow Research Centre at the University of Surrey. The new project will make extensive use of its wind tunnel facilities. For more information on EnFlo, visit the website at www.vortex.mech.surrey.ac.uk/FRC/enflo_home.html.
The project will run in parallel with the DAPPLE (Dispersion of Air Pollution and Penetration into the Local Environment) initiative, also funded by EPSRC. DAPPLE is a four-year project involving the Universities of Bristol, Cambridge, Leeds, Reading and Surrey, and Imperial College London. Its aim is to increase understanding of vehicle emissions, pollutant dispersion and exposure to pollution in realistic urban environments, and so make possible the improvements necessary to enable the better planning and management of urban air quality. For more information on DAPPLE, visit the website at www.dapple.org.uk
The Engineering and Physical Sciences Research Council (EPSRC) is the UK's main agency for funding research in engineering and the physical sciences. EPSRC invests more than £500 million a year in research and postgraduate training to help the nation handle the next generation of technological change.
The areas covered range from information technology to structural engineering, and from mathematics to materials science. This research forms the basis for future economic development in the UK and improvements in everyone's health, lifestyle and culture.
EPSRC also actively promotes public awareness of science and engineering. EPSRC works alongside other Research Councils with responsibility for other areas of research. The Research Councils work collectively on issues of common concern via Research Councils UK.
Website address for more information on EPSRC: www.epsrc.ac.uk