REC was commissioned to undertake an Air Quality Assessment in support of a residential development in Warrington. The proposals included the conversion of a grade II listed building into five dwellings and the construction of a further nine new mews dwellings. The site was located in an area identified by Warrington Borough Council as having elevated pollutant concentrations due to road vehicle exhaust emissions. An Air Quality Assessment was therefore required in order to quantify pollution levels at the site and assess the suitability for residential end use.
Dispersion modelling using ADMS-Roads was undertaken in order to predict pollutant concentrations across the proposed development as a result of emissions from the local highway network. Results were subsequently verified using pollution monitoring results obtained from Warrington Borough Council.
The results of the dispersion modelling assessment indicated that predicted annual mean concentrations of nitrogen dioxide were just below the relevant air quality standard across the proposed development. This was consistent with local pollutant monitoring results and was expected due to the concerns previously raised by Warrington Borough Council.
Although exceedances of the relevant standards were not predicted at proposed residential property locations, due to uncertainty associated with dispersion modelling, a number of suitable mitigation options were suggested in order to reduce the potential for future exposure to elevated pollutant levels. This will help protect the health of future residents and reinforce the developer’s environmental credentials.