Air Quality Assessment – London & Quadrant (Former Citroen Site), Brentford



L&Q is a regulated charitable housing association and houses 250,000 people in 95,000 homes across London and the South East.

In 2017 L&Q announced its wish to regenerate the site of the former Citroen car dealership on Capital Interchange Way in Brentford, west London for a mixed-use scheme of 441 residential units including 50{e56040049d2bd1cefe8a397fbf7aeb0cd0861f8b0598f2148e35f875d415f790} affordable housing with ancillary facilities, flexible uses and a nursery.


REC was commissioned by L&Q to undertake an Air Quality Assessment and input into the EIA for the planning application.

The development is located within the London Borough of Hounslow Air Quality Management Area (AQMA) designated due to exceedances of the annual mean Air Quality Objective (AQO) for nitrogen dioxide (NO2). An air quality assessment was therefore undertaken to determine baseline conditions, consider potential exposure as a result of the development and also provide consideration of potential effects as a result of the construction phases of the proposal scheme.

The construction phase of the development could potentially result in air quality impacts as a result of fugitive dust emissions from the site. These were assessed in accordance with the Greater London Authority (GLA) methodology.

REC also undertook dispersion modelling for the client in order to predict air quality impacts during the operational phase as a result of road vehicle exhaust emissions. Although there were no predicted exceedances of the annual mean air quality objective for NO2 at any sensitive locations across the proposed development, elevated levels of NO2 were predicted at floor level and thus REC advised on specific mitigation measures to protect future users from elevated concentrations.

The London Plan states that new developments must be considered ‘air quality neutral’. Pollutant emissions associated with energy consumption within the development and traffic generation from it were compared to relevant benchmarks. The results of the air quality neutral assessment concluded that the combined annual emissions were predicted to be below the combined benchmark level. Therefore, the proposed development could be considered air quality neutral.

Solution & Result

Based on the assessment results the site was considered suitable for the proposed end use and compliant with the London Plan, the London Borough of Hounslow Local Plan and relevant legislation – subject to the inclusion of relevant mitigation measures.

The London Borough of Hounslow had originally refused the application on the grounds of the scheme potentially impacting on historic buildings in the world heritage site at the nearby Royal Botanic Gardens Kew. The Mayor took over the determination of the planning application. The application went to a planning hearing and REC appeared at the Mayoral representation hearings at London City Hall as the air quality expert witness. REC’s supported the client’s application by responding to any air quality related objections and queries.

Following on from the hearing, the client was granted planning permission.

citroen site