Air Quality Assessment vs Dust Impact Assessment
Two different reports, two different phases of your development. An AQA addresses the operational phase; a DIA addresses construction-phase dust. Most planning applications need both — here is a plain-English guide to what each covers.
Same Site, Different Phases — Different Reports
An Air Quality Assessment (AQA) addresses what happens once your development is finished and operational — the long-term pollutant concentrations that future residents, workers and neighbours will be exposed to. It quantifies nitrogen dioxide (NO2) and particulate matter (PM10, PM2.5) from operational traffic and combustion plant against the UK Air Quality Objectives (NO2 40 µg/m³ annual mean, PM10 40 µg/m³ annual mean, PM2.5 20 µg/m³ annual mean after 2028), and follows the IAQM/EPUK 2017 framework.
A Dust Impact Assessment (DIA) addresses the construction phase — the demolition, earthworks, construction and trackout activities that can release coarse dust to neighbouring receptors. It follows the IAQM 2024 v2.2 construction dust guidance (Assessment of Dust from Demolition and Construction), which classifies the risk of each activity using site-specific parameters (dust class of materials, magnitude of works, distance to receptors) and identifies the mitigation needed to reduce the residual risk to "not significant".
The two reports look at different pollutants over different timescales using different methodologies, but they share a lot of the underlying site information — receptor identification, baseline air quality, AQMA status, sensitivity classification — so they are most efficiently produced as a combined package. Within an EIA, they typically sit in the same Air Quality chapter, with a clear construction-phase section (DIA) and operational-phase section (AQA).
Malcolm Pounder CEnv MIAQM produces both, personally, and we routinely deliver combined AQA + DIA packages for residential, commercial, industrial and mixed-use schemes across the UK.
AQA vs DIA — Side by Side
Two distinct reports, both commonly required for the same planning application. Here is what each one covers.
| Air Quality Assessment (AQA) | Dust Impact Assessment (DIA) | |
|---|---|---|
| Purpose | Demonstrate the development's operational air quality effect is acceptable. | Demonstrate construction-phase dust risk can be mitigated to "not significant". |
| Phase | Operational (post-occupation, long-term). | Construction (demolition, earthworks, construction, trackout). |
| Pollutants | NO2, PM10, PM2.5 — long-term mean and short-term percentile concentrations. | Coarse dust (deposition, soiling, PM10) and PM2.5 from construction activities. |
| Guidance | IAQM/EPUK 2017 Planning for Air Quality, NPPF, PCM background mapping (DEFRA). | IAQM 2024 v2.2 Assessment of Dust from Demolition and Construction. |
| Methodology | Screening or detailed dispersion modelling (ADMS-Roads) of operational traffic and plant emissions. | Activity-based risk classification: dust class × magnitude × receptor sensitivity, then mitigation appraisal. |
| Cost | Higher when detailed modelling required; lower for screening only. | Usually fixed-fee and self-contained — cost varies with scheme size and receptor count. |
| Timescale | Screening: 3–5 working days. Detailed: 2–4 weeks. | Typically 5–10 working days. |
| Typical deliverable | AQA report or EIA air quality chapter with modelled receptor results and significance evaluation. | Stand-alone DIA report (often appended to the AQA) classifying activity risk and listing mitigation. |
Combined and Stand-Alone Packages
Whether you need just an AQA, just a DIA, or both as a combined package, we deliver to a standard that satisfies the LPA.
Stand-Alone AQA
Operational-phase Air Quality Assessment for residential, commercial or mixed-use schemes. Screening (IAQM/EPUK 2017) or detailed (ADMS-Roads dispersion modelling) depending on scheme scale and AQMA proximity, with significance evaluation and mitigation as required.
Stand-Alone DIA
Construction-phase Dust Impact Assessment to IAQM 2024 v2.2, covering demolition, earthworks, construction and trackout activities. Activity-based risk classification, receptor sensitivity mapping and a full mitigation schedule to support pre-commencement condition discharge.
Combined AQA + DIA Package
The most common option: a single combined report covering both operational air quality and construction dust, presented as separate clearly-labelled sections within one document. More efficient than commissioning them separately because the baseline data, receptor mapping and AQMA review are shared.
EIA Air Quality Chapter
For larger schemes that require EIA, we produce a full Air Quality chapter that integrates the AQA (operational) and DIA (construction) into a single chapter, with consistent significance terminology, cumulative effects assessment and cross-references to the CEMP. Written to satisfy planning inspectors and statutory consultees.
Schemes That Usually Need Both Reports
Most planning applications of any meaningful scale need both an AQA and a DIA. The reason is that the LPA's environmental health team is concerned about both the construction phase (dust nuisance to neighbours) and the operational phase (long-term exposure of new and existing residents to traffic pollutants).
For very small schemes, sometimes only a DIA is required. For schemes with no demolition or earthworks and minimal traffic generation, sometimes only an AQA. We will tell you honestly which apply.
- 50+ dwelling residential schemes
- Mixed-use developments
- Logistics and warehousing
- Schemes in or near an AQMA
- Demolition + new build sites
- EIA-screened developments
- Schools, care homes, hospitals
- Industrial estates
Frequently Asked Questions
AQA vs DIA — what's the difference?
An Air Quality Assessment (AQA) deals with the operational phase of a development — once the scheme is built and in use — and quantifies long-term pollutant concentrations such as nitrogen dioxide (NO2) and particulate matter (PM10, PM2.5) from traffic and combustion sources against the UK air quality objectives. A Dust Impact Assessment (DIA) deals with the construction phase: demolition, earthworks, construction and trackout activities that can release coarse dust (PM10 and larger). They use different methodologies, address different pollutants over different timescales, and most major planning applications need both.
Do I need both an AQA and a DIA?
Most schemes that trigger an AQA also need a DIA, and vice versa, because the local validation list and IAQM guidance treat construction-phase dust and operational-phase air quality as separate but related issues. A typical 50-dwelling residential scheme close to existing housing will need a DIA at minimum, and may need an AQA if it generates above-threshold traffic or sits within an AQMA. Major schemes and EIA applications almost always need both.
Can one consultant produce both an AQA and a DIA?
Yes — and in practice the same consultancy usually does both, because the underlying data (site location, receptor mapping, baseline conditions, AQMA proximity) is shared between the two reports. We routinely deliver combined AQA + DIA packages, which is more efficient than commissioning them separately, and we make sure the documents reference each other consistently — particularly within an EIA chapter.
What about a CEMP — is that the same as a DIA?
No, but they are closely linked. The Dust Impact Assessment is the pre-application/planning-stage technical study that establishes the risk and required mitigation. The Construction Environmental Management Plan (CEMP) Air Quality section is the pre-commencement document that translates that mitigation into deliverable on-site controls, monitoring locations, complaint procedures and trigger levels — it is what the contractor actually works to. Many planning consents condition both.
What about odour — different again?
Yes. Odour assessments are a separate discipline using IAQM 2018 odour guidance, FIDOL/FIDOR analysis and (for kitchen extracts) the EMAQ+ 2018 framework. Odour deals with the perceptible nuisance of smells from sources such as restaurant extracts, sewage works, food processing or composting. We provide odour assessments alongside AQA and DIA where the scheme requires it — see our restaurant and odour services pages.