Air Pollution Services (APS), an independent professional air quality consultancy, was engaged by the CVNF to review the evidence presented by the Council. APS raised areas of major concern.

Not applying planning system guidance for ‘Affected roads’

Calderdale’s AQA scoping method to define ‘affected roads’ that should be included a combination of methods, rather than using the planning system recognised guidance written by the Environmental Protection UK and the Institute of Air Quality Management. APS maintains that applying the ‘industry-standard approach would have resulted in more roads included in the air quality model’. Adding more roads to the air quality model means more properties will likely be identified where the local plan has adverse impacts.

Traffic data

The CVNF have consistently challenged the quality of the traffic data Calderdale continue to rely upon.

CVNF commissioned independent experts, Traffic, Transport and Highways Consultants (TTHC), who found that Calderdale’s 12-years old Strategic Transport Model (CTSM) has data gaps and does not consider public transport and does not represent the levels of congestion in and around Brighouse.  These concerns were first submitted as part of the Regulation 18 consultation and have recently been challenged by the council.

We’ll return to the issue of traffic data in another article. Still, it’s important to understand that traffic data is a key input into an air quality model. The Forum’s professional consultants continue to raise concerns about the quality of traffic data (concerns shared by the West Yorkshire Combined Authority) who awarded Calderdale over £600,000 to produce a new model.

Model Verification

Calderdale’s consultants admit the input data includes predicted traffic flow ‘which are subject to uncertainty.’

It’s essential to have a clear understanding of the locations and likely concentrations of pollution in confirming the suggested outcome is accurate.

We know that some air quality monitoring locations were excluded from the model verification. As APS found, ‘this means it is highly likely that the modelling carried out underpredicts concentrations in many areas’.

Impacts in South-East Calderdale

Calderdale’s consultants think air quality will slightly improve in Brighouse, and yet two strategic sites and an industrial estate are planned for the area. During the Local Plan Examination, it became clear the strategic link road had been cancelled in favour of a ‘spine road’ going through the sites. This is significant because the council believes the developments in SE Calderdale will improve air quality. Still, with nearly 50% of Calderdale’s planned development, there is limited evidence as to how these improvements will help air quality in Brighouse.