Industrial developments face tougher air quality scrutiny than almost any other type of scheme. Between a busy planning process and, very often, a separate environmental permit, an industrial project can need two different air quality assessments looking at two different things. Get either wrong and you’re facing objections, delays, or refusal.

This guide explains what an air quality assessment for an industrial development involves, when you need one, how the planning and permitting sides fit together, what it costs, and the mistakes that hold projects up.

What is an air quality assessment for industrial developments?

An air quality assessment for an industrial development is a technical study of how the site’s emissions will affect local air quality, and whether those effects are acceptable under UK planning and permitting rules. It looks at pollutants from the site’s processes, plant and traffic, predicts where they’ll go, and compares the results against national air quality objectives.

Industrial sites are different from housing or commercial schemes in one important way: they often release pollutants from fixed points such as chimneys, flues and process stacks, on top of the emissions from vehicles coming and going. That means the assessment usually has to deal with both point-source emissions and traffic emissions together.

When does an industrial development need an air quality assessment?

You’ll usually need one if any of these apply:

• The development introduces combustion plant such as boilers, generators, furnaces or a combined heat and power (CHP) unit
• The process releases pollutants through a stack or flue
• The site will attract significant HGV or vehicle traffic
• The development is in, or near, an Air Quality Management Area (AQMA)
• There are sensitive receptors nearby homes, schools, hospitals or care homes
• The site needs an environmental permit from the Environment Agency

In practice, most sizeable industrial schemes trigger at least one of these, which is why air quality is best considered right at the start rather than bolted on before submission.

The two sides: planning and permitting

This is the part the other guides miss, and it’s the thing that catches industrial developers out. An industrial project can need two separate air quality assessments for two separate consenting processes.

Feature	Planning air quality assessment	Environmental permit air quality assessment
Who assesses it	Local planning authority	Environment Agency (or SEPA / NRW)
Main focus	Traffic emissions, construction dust, effect on nearby receptors	Process and stack emissions from the operation itself
Typical method	IAQM guidance, dispersion modelling of road traffic	EA H1 risk assessment, stack dispersion modelling
When it’s needed	To support the planning application	To obtain a permit to operate

The two often overlap and should be planned together. Running them in isolation is a common and expensive mistake the emissions data, modelling and receptor information can usually be shared across both.

What does the assessment cover?

An industrial air quality assessment typically looks at several emission sources at once.

Point source (stack) emissions. Where a process releases pollutants through a chimney or flue, the assessment models how those emissions disperse and where they land. This is central to any environmental permit application and often feeds into a stack height assessment to make sure the discharge point is tall enough.

Combustion plant. Boilers, generators and CHP units release nitrogen oxides (NOx) and other pollutants. These are modelled against the relevant objectives.

Traffic emissions. HGVs and staff vehicles add roadside pollution, particularly NO2 and particulate matter. This is usually assessed with dispersion modelling of the local road network.

Construction and dust. During the build, demolition and earthworks can generate dust, usually managed through a construction dust assessment and a dust management plan.

How the assessment process works

Step 1 — Scoping. We confirm what’s needed for both planning and permitting, identify the emission sources and the sensitive receptors, and agree the approach with the authorities where useful.

Step 2 — Baseline. We establish existing air quality around the site using background concentration data and, where required, air quality monitoring.

Step 3 — Modelling. We use dispersion modelling typically ADMS to predict how emissions from stacks, plant and traffic will affect concentrations at nearby receptors.

Step 4 — Assessment and mitigation. We compare the predicted levels against the national air quality objectives and, if needed, recommend mitigation such as taller stacks, cleaner plant, or emission controls.

Step 5 — Reporting. You receive a clear report suitable for the planning application, the permit application, or both.

What does an industrial air quality assessment cost?

Because industrial assessments usually involve stack modelling and multiple emission sources, they sit at the more detailed end of the scale.

A full assessment for an industrial development generally ranges from around £3,000 to £12,000 or more, depending on the number of sources, whether both planning and permitting are involved, and the complexity of the modelling.

Preparation typically takes four to eight weeks, sometimes longer where baseline monitoring is required first.

A real project example

We supported an industrial operator whose site needed both planning permission and an environmental permit for new combustion plant. The two processes were originally being handled separately by different parts of the project team, which risked duplicated work and inconsistent emissions figures.

We brought the air quality work together: a single emissions inventory feeding both the planning assessment and the permit’s stack dispersion modelling.

That kept the figures consistent across both applications, avoided repeating the modelling twice, and gave both the council and the Environment Agency the evidence they needed. The result was a smoother approval on both fronts and a lower overall cost than running the two in isolation.

The lesson: on industrial schemes, joining up planning and permitting early saves both time and money.

Common mistakes to avoid

• Treating planning and permitting separately. They share data. Running them in isolation duplicates cost and risks inconsistent figures.
• Leaving air quality until pre-submission. Stack heights and plant choices are hard to change late. Assess early so the design can respond.
• Underestimating stack modelling. Point-source dispersion is the technical heart of an industrial assessment and needs proper modelling, not a screening shortcut.
• Forgetting cumulative impact. Other nearby industrial sources may need to be included. Missing them is a common reason for objections.
• Specifying plant before assessing it. Choosing boilers or generators before checking their emissions can force an expensive redesign.

How FreshBreeze can help

We prepare air quality assessments for industrial developments across London, Birmingham and Manchester, covering both planning applications and environmental permits.

From stack dispersion modelling to construction dust, we join the pieces up so you’re not paying for the same work twice. Learn more about our air quality assessment services or our support with environmental permit applications.

Conclusion

Air quality is one of the biggest technical hurdles an industrial development has to clear, precisely because it usually sits across two consenting processes at once planning and permitting.

The projects that move smoothly are the ones that treat air quality as a single joined up piece of work from the start: one emissions inventory, consistent modelling, and early design decisions on plant and stack heights.

Handle it that way and it becomes a manageable step rather than the thing standing between you and consent to build and operate.

Frequently asked questions