Air quality assessments for planning applications

Planning applications for proposals that generate pollutants or increased traffic emissions or combined heat and power plant / biomass boilers may require an air quality assessment.

When is an air quality assessment needed?

As a general rule, an air quality assessment will be required where the development is anticipated to give rise to significant changes in air quality.  

The decision as to whether or not an air quality assessment is required should take into account the:

• physical characteristics and scale of the proposals
• changes in traffic flows predicted to arise
• the proposals for Combined Heat and Power (CHP) plant or stand alone boilers burning biomass, and
• the air quality sensitivity of the location.

Criteria

Proposals that fit any of the criteria below will require an air quality assessment.

• Increase in traffic congestion (increase in stop start driving)
• Significant changes to traffic volumes or speed of traffic, typically a change in:
  • annual average daily traffic (AADT) or peak traffic flows of greater than ±5% or ±10%, depending on local circumstances (a change of ±5% will be appropriate for traffic flows within an AQMA) and / or
  • vehicle speed (typically of more than ±10 kph) 
  • usually on a road with more than 10,000 AADT (5,000 if 'narrow and congested')
• Significant changes to the type of traffic on local roads, increase the proportion of HDVs by say 10% or more, due to the development of a bus station or an HGV park
• More than 100 car parking spaces outside an AQMA or 50 inside an AQMA and the number of vehicles entering and leaving
• Developments in ecological sites or areas of poor air quality
• Inclusion of biomass boilers or CHP plant
• Potential impacts to local residents during construction - eg HGVs travelling to and from large building sites 

Environmental Protection UK offers further guidance.

Biomass boilers

Please see additional guidance on biomass boilers.