Redmore Environmental was commissioned to undertake an Air Quality Assessment, including an Ambient Air Quality Monitoring survey in support of a Multi-Storey Car Park on the site of the current surface Broad Street car park, Smithfield. The proposals comprised 734 new parking spaces across 6 storeys to provide additional car parking for Stoke-on-Trent city centre.
Multi-Storey Car Park Air Quality Assessment Context
There was the potential for the Multi-Storey Car Park to cause air quality impacts as a result of fugitive dust emissions during construction works and road traffic exhaust emissions from vehicles travelling to and from the site, as well as movements within the development itself, during the operational phase. A two staged assessment was therefore undertaken in order to determine baseline conditions and consider potential effects as a result of the development.
Baseline Air Quality Monitoring
Baseline monitoring of nitrogen dioxide (NO2) was requested by Stoke-on-Trent City Council in order to define ambient concentrations in the vicinity of the site. This was therefore undertaken using passive diffusion tubes, an effective way of monitoring long-term pollution levels, particularly at roadside locations. After consultation with Stoke-on-Trent City Council, it was agreed the survey would be conducted in triplicate at two locations over a 3-month period, with each set of diffusion tubes exposed for approximately 4-weeks in line with the Department for Environment, Food and Rural Affairs (DEFRA) monitoring calendar. Once the survey was complete, the results were annualised and bias-adjusted in accordance with the DEFRA guidance ‘Local Air Quality Management (LAQM) TG16’. The results of the diffusion tube survey were later used in the dispersion modelling verification process.
Multi-Storey Car Park Air Quality Assessment Findings
Construction of the development may result in air quality impacts as a result of fugitive dust emissions. These were assessed in accordance with the Institute of Air Quality Management (IAQM) guidance ‘Assessment of dust from demolition and construction V1.1’. Following the analysis it was concluded that good practice control measures would reduce dust emissions to an acceptable level during the relevant work phases.
A dispersion modelling assessment was carried out using ADMS-Roads in order to determine potential impacts associated with exhaust emissions associated with vehicle movements generated by the site. Two scenarios were modelled in order to predict pollutant concentrations both with and without the development in place.
Emissions associated with vehicle movements within the existing and proposed car parks were included within the dispersion model using methodology provided by Cambridge Environmental Research Consultants (CERC). This considered the dimensions of the car parks to ensure releases throughout the relevant structures were included in the results.
The results indicated the Multi-Storey Car Park was not predicted to significantly affect existing air quality conditions within the vicinity of the site. As such, mitigation measures were not considered necessary.
How Can We Help?
If you require a diffusion tube survey to determine baseline conditions or an Air Quality Assessment in support of a Multi-Storey Car Park, then please get in touch with a member of the team today to find out how we can help you.