If you’re planning construction work anywhere in the UK, the way your dust risk is assessed has changed. The Institute of Air Quality Management (IAQM) updated its construction dust guidance to Version 2.2, and the changes are significant enough that the same site can now land in a completely different risk band than it would have a few years ago.
For some developers that means less mitigation and lower costs. For others it means an unexpected requirement for months of baseline monitoring before a single machine turns up on site.
This guide explains what actually changed, what it means in practice, and what you should do about it.
What is the IAQM 2024 dust guidance?
The IAQM 2024 dust guidance (Version 2.2) is the updated UK framework for assessing dust from demolition and construction. It replaces the 2014 version and sets out how consultants judge dust risk, what mitigation is expected, and when monitoring is required.
It’s the document local planning authorities across the UK reference when they review a construction dust assessment, so it directly shapes what your planning conditions will say.
What changed in the IAQM 2024 dust guidance?
The headline change is to the dust emission magnitude thresholds the site sizes and building volumes that determine whether your project is rated Large, Medium, or Small for each phase of work. Here’s the comparison.
| Phase | 2014 Guidance | 2024 Guidance (V2.2) |
|---|---|---|
| Demolition | Large: >50,000 m³ Medium: 20,000–50,000 m³ Small: <20,000 m³ | Large: >75,000 m³ Medium: 12,000–75,000 m³ Small: <12,000 m³ |
| Earthworks | Large: >10,000 m² Medium: 2,500–10,000 m² Small: <2,500 m² | Large: >110,000 m² Medium: 18,000–110,000 m² Small: <18,000 m² |
| Construction | Large: >100,000 m³ Medium: 25,000–100,000 m³ Small: <25,000 m³ | Large: >75,000 m³ Medium: 12,000–75,000 m³ Small: <12,000 m³ |
| Trackout | Large: >50 HDV movements/day Medium: 10–50 HDV/day Small: <10 HDV/day | Large: >50 HDV movements/day Medium: 20–50 HDV/day Small: <20 HDV/day |
The earthworks change is the one everyone talks about, and rightly so. The Large threshold moved from 10,000 m² to 110,000 m² eleven times higher. Under the old guidance, almost any ordinary urban site was classed as Large simply because of its area. That was never the intention.
The new figure reserves “Large” for genuinely major operations like infrastructure projects and strategic masterplans.
But look carefully at the other rows, because two of them go the other way. Demolition and construction thresholds have come down, meaning smaller buildings now fall into higher risk bands than before. A demolition job that was Small under the old rules could now be Medium.
How the changes work in practice
Take a real-world example: demolishing a 15,000 m³ building on a one hectare (10,000 m²) site.
Under the 2014 guidance, that demolition would have been Small (under 20,000 m³), while the earthworks would have been Large (10,000 m² hits the threshold).
Under the 2024 guidance, it flips completely. The demolition becomes Medium (15,000 m³ sits in the 12,000–75,000 band), and the earthworks drop to Small (10,000 m² is well under 18,000 m²).
Same site, same job, completely different risk profile and a different set of planning conditions as a result.
Why the PM2.5 focus matters
The 2024 guidance puts much more emphasis on PM2.5 the fine particles small enough to pass deep into the lungs and enter the bloodstream. The older framework leaned heavily on PM10 and dust soiling, essentially treating dust as a nuisance issue.
In practice this doesn’t usually mean extra fieldwork. What it changes is how the assessment is written and how mitigation gets justified.
If your site sits near a school, hospital, care home, or anywhere with vulnerable people, the health angle now tends to push you towards a higher tier of mitigation than site size alone would suggest. Receptor sensitivity carries more weight than it used to.
Screening at outline planning stage
One genuinely useful addition is the recommendation to screen dust risk at outline planning application stage, with the detailed work following at reserved matters or full application.
The old guidance said little about outline stage, so dust was often ignored until reserved matters by which point the site layout was fixed and any design fix was expensive or impossible.
A screening note at outline is short, usually four to six pages, and answers three questions: will a detailed assessment be triggered later, roughly what magnitude band are we looking at, and what should the design team factor in now?
It isn’t mandatory, but many councils now expect it, particularly on dust-sensitive sites.
The baseline monitoring trap most developers miss
This is the point that catches people out, and it’s barely mentioned anywhere else.
Medium risk projects are normally expected to carry out continuous particulate monitoring. And some councils will ask for up to three months of baseline monitoring before construction even begins, so there’s data showing what the pollution levels were beforehand.
That’s a three month hole in your programme if nobody spotted it. Because the demolition and construction thresholds dropped, more schemes are now landing in Medium than before, which means more schemes are hitting this requirement unexpectedly.
If you’re planning a project in a city where councils take this seriously, factor it in early not when you’re trying to discharge a pre commencement condition.
Our air quality monitoring team can advise on what baseline data your local authority is likely to want.
Changes to mitigation expectations
The mitigation measures in the 2024 guidance will look familiar, but several have been tightened:
- Wheel washing has shifted from “recommended” to normally required on any site rated Medium or above
- Hoarding specifications now address fine particulate, not just visible dust
- NRMM (non-road mobile machinery) engine standards are pushed harder, with London applying stricter requirements of its own
- Real-time PM10 monitoring at the site boundary is now the expected baseline on higher-risk sites rather than an optional extra
All of this normally sits within your dust management plan or the air quality section of a CEMP.
What this means for your project — a real example
We recently reviewed a mixed-use scheme in the West Midlands where the developer was working from a dust assessment prepared under the old 2014 framework. The site had been classed as high risk largely because of its area, and the resulting conditions required an extensive mitigation package.
Re-running the assessment under the 2024 thresholds dropped the earthworks magnitude by two bands. The demolition element moved up slightly, but the overall risk rating fell.
We revised the dust management plan to match the actual risk, and the client avoided a significant chunk of unnecessary monitoring and mitigation cost without weakening the planning case at all.
That’s the practical takeaway: if you’re carrying an assessment written before 2024, it’s worth a second look.
Common mistakes to avoid
- Assuming the change only helps you. Earthworks thresholds went up, but demolition and construction came down. Check all four phases, not just the headline.
- Forgetting trackout. The Medium band tightened from 10 to 20 HDV movements. Sites with long unpaved haul routes often find trackout becomes the dominant phase.
- Leaving baseline monitoring too late. Three months of pre-construction data can’t be produced retrospectively.
- Relying on an old assessment. A report written under the 2014 rules may no longer reflect the correct risk band in either direction.
- Ignoring nearby receptors. With site area mattering less, proximity to schools, hospitals and care homes matters more.
What should you do now?
If you have a live or upcoming project, work through these steps:
- Check when your dust assessment was written. Anything prepared before 2024 should be reviewed against the current thresholds.
- Calculate all four phases separately. Demolition volume, earthworks area, construction volume, and daily HDV movements each have their own band.
- Map your sensitive receptors. Schools, hospitals, care homes and ecological sites all push the outcome upwards.
- Check your council’s monitoring expectations early. Especially if baseline data might be required.
- Get a screening note at outline stage if your scheme is going through outline planning.
Conclusion
The IAQM 2024 dust guidance is the most significant change to UK construction dust assessment in a decade. The earthworks threshold jump from 10,000 m² to 110,000 m² grabs the attention, but the quieter changes matter just as much lower demolition and construction thresholds, a tighter trackout band, a stronger focus on PM2.5 and vulnerable receptors, and firmer expectations around monitoring.
If you’re working from an assessment written before 2024, get it checked. The bands may have moved in your favour, or they may have moved against you, and it’s far cheaper to find out now than at condition-discharge stage.
Frequently asked questions
It’s the updated UK framework (Version 2.2) for assessing dust from demolition and construction, published by the Institute of Air Quality Management. It replaced the 2014 version and is used by local planning authorities to review construction dust assessments.
The Large-magnitude earthworks threshold increased from 10,000 m² to 110,000 m². Medium is now 18,000–110,000 m², and Small is under 18,000 m².
Not always. Earthworks thresholds went up, so many sites drop a band. But demolition and construction thresholds came down, so some projects now sit in a higher band than before. You need to check each phase.
It’s worth reviewing. An assessment prepared under the 2014 framework may put your site in the wrong band now sometimes too high, sometimes too low. A short review is usually quick and inexpensive.
Typically for sites classed as Medium risk or above. Some councils also request up to three months of baseline monitoring before construction starts, so check requirements early.
No. The framework remains qualitative. There’s no dispersion modelling of construction dust and no numerical concentration limits at receptors professional judgement still applies.
