Yelverton Road - Air Quality Assessment and Air Quality Neutral Calculation for a residential development

We carried out an air quality assessment and air quality neutral calculation on behalf of Cherwell Group for a development on Yelverton Road; a part three storey, part 17 storey mixed-use development with a basement which includes residential dwellings, offices and creative workspaces.

Challenge

The key challenges were demonstrating that the development would not adversely affect existing air quality and that the site would not expose new occupants to unacceptable levels of air pollution.

The development has the potential to affect air quality when the existing buildings on the site are demolished, during earthworks on the site and when the new building is constructed. These activities can lead to an increase in dust deposited on surfaces and an increase in particles suspended in the air. There is also the potential for dust to be tracked out when vehicles access the site.

Once the development is occupied, it may generate vehicle movements. As the site is in an AQMA, designated due to high pollution levels attributable to road traffic emissions, the planning application needed to be accompanied by an assessment that demonstrated that the development would not affect the council’s plans to improve air quality.

Solution

For the construction phase, we undertook a dust impact risk assessment. We were then able to use the risk to identify proportionate measures to mitigate against the risk of impacts.

The likely number of generated vehicle movements was found to be well below the criteria requiring an assessment. This allowed us to conclude that emissions from vehicle movements generated by the development were unlikely to affect the AQMA.

We used an advanced dispersion modelling (in this case, ADMS-Roads) to predict concentrations of NO₂ and PM₁₀ at the façades of the building to determine how future occupants would be affected.

A six-month passive NO₂ diffusion tube monitoring study was also undertaken. This involved our consultants visiting the site once a month to install and collect samplers. At the end of the six-month period, the consultant was able to compare the model output with the measurements, ensuring that any uncertainty in the model predictions was acceptable.

The model showed that the predicted pollutant concentrations were within the health-based objectives assisting the development in gaining planning permission.