Northolt Road - Air Quality Assessment

Southdowns was commissioned to provide an air quality assessment to accompany the planning application for a residential development alongside the A312. The assessment of the potential impacts of introduction of new residential receptors to an area of poor air quality necessitated a dispersion model of the proposed development and the road network in the area.

With the location of the development adjacent to the a busy road in an Air Quality Management Area it could introduce new receptors to NO2 concentrations above the annual mean and hourly mean limit values. An emissions projection risk assessment was also conducted to model the NO2 concentrations if emissions do not decline according to Defra projections. To ensure that future occupants were not exposed to NO2 concentrations above limit values it was proposed to supply mechanical ventilation from the fa├žade away from the road. The reduction in vehicle movements associated with the development showed an improvement in air quality with the proposed development at nearby receptors.

To ensure that emissions from the proposed development were in line with the emissions benchmarks of the London Plan the building emissions from the heating plant and the transport emissions from car use were calculated. The calculated emissions were the compared to the building and transport emission benchmarks to demonstrate the proposed development was complaint with the Air Quality Neutral Policy.