ClearfLo: Clean Air for London

Lead Research Organisation: University of Hertfordshire
Department Name: Science and Technology RI


Poor air quality, particularly in urban areas, has a demonstrable effect on human health, but the processes responsible for producing the main pollutants, namely particulate matter, ozone, nitrogen dioxide and heat are not well understood and are poorly predicted. The ambition of ClearfLo is to provide integrated measurements of the meteorology, composition and particulate loading of London's urban atmosphere, made at street level and at elevated sites, complemented by modelling, to improve predictive capability for air quality. This ambition will be addressed by establishing new measurement capabilities in London, which will be used for long-term measurements and intensive observation periods, and by analysis and modelling of the measurements to establish key processes.


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Bohnenstengel S (2015) Meteorology, Air Quality, and Health in London: The ClearfLo Project in Bulletin of the American Meteorological Society

Description Air quality and heat are strong health drivers and their accurate assessment and forecast is important in densely populated urban areas. However, the source and processes leading to high concentrations of main pollutants such as ozone, nitrogen dioxide, and particulate matter in complex urban areas are not fully understood limiting our ability to forecast air quality accurately.
The spatial variability of nitrogen oxides (NOx) concentrations have been calculated by the Community Multiscale Air Quality (CMAQ) modelling system at a horizontal grid resolution of 6 km to illustrate the urban increment in NOx. CMAQ, accounts for the distribution of emissions sources, long-range transport and the ability of London's atmosphere to dilute pollutants. The long-term numerical simulations with the CMAQ modelling system complemented by case studies with the AQUM and UKV are expected to provide a detailed picture of the processes driving the spatial and temporal distribution of the urban increment in future papers.
Numerical simulations have been conducted using the Weather Research and Forecast numerical model to examine the effects of a marine air intrusion (including a sea-breeze front), in an easterly wind regime on 7 May 2008, on the structure of London's urban heat island (UHI). Frontal advection across London effectively replaces the air in the urban area. Results indicate that there is a delicate balance between the effects of thermal advection and urbanization on near-surface fields, which depend, inter alia, on the parametrization of the urban canopy and the urban land-cover distribution.
Exploitation Route The work has considerable implications for city authorities and national policy makers. The new approaches provide more realiable and science based predictions of air pollutants such as ozone and particulate matter both of whuch are associated with adverse health and environmental impact. The need for accounting contributions of regional air pollution to the air quality within cities is vital when devising air quality and health management strategies.
Sectors Environment

Description The project has had a major overall impact on advancing the science of urban air quality and in highlighting the implications to users including policy makers. The modelling work conducted by UH has formed the basis of a contract funded by DEFRA on developing a regional modelling capability for UK air quality policy applications.
First Year Of Impact 2012
Sector Environment
Impact Types Policy & public services

Description Framework Programme 7
Amount € 1,100,000 (EUR)
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 01/2010 
End 06/2014