Construction Dust Risk Assessment (CDRA)
The methodology we use follows the IAQM Guidance on the Assessment of Dust from Demolition and Construction (updated January 2024). This is the nationally recognised framework and the one that local planning authorities and environmental health teams expect to see applied.
What Is a Construction Dust Risk Assessment?
A Construction Dust Risk Assessment — commonly referred to as a CDRA, or sometimes an Air Quality Dust Risk Assessment (AQDRA) — is a technical report that evaluates the risk of dust and particulate matter generated during demolition, construction, and earthworks activities affecting nearby sensitive receptors. It's a planning requirement that is becoming increasingly standard across London and the wider South East, and one that developers often underestimate until a planning officer's pre-commencement condition lands on their desk.
The purpose of the assessment isn't simply to tick a box. It's to demonstrate, through a structured and evidence-based methodology, that the potential dust impacts of a development have been properly considered and that proportionate mitigation measures will be in place before and throughout construction. Get it right at the planning stage and you avoid costly delays on site.
When Is a CDRA Required for Planning?
There's no single national threshold that triggers a mandatory CDRA requirement — it varies between local planning authorities and depends on the nature of the proposal and the surrounding environment. In practice, however, you're likely to need one if:
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The development involves demolition of existing structures, particularly larger or older buildings that may contain hazardous materials.
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Significant bulk earthworks are proposed — typically anything over one metre depth or a large surface area.
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There are sensitive receptors within 350 metres of the site boundary, such as residential properties, schools, hospitals, care homes, or designated ecological sites.
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The site is within or adjacent to an Air Quality Management Area (AQMA).
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The LPA's local validation checklist specifically requires it — as many London boroughs and authorities across Kent and Essex now do.
Even where a CDRA isn't explicitly listed as a validation requirement, submitting one proactively is good practice. It reduces the risk of pre-commencement conditions being imposed and demonstrates to officers that dust impacts have been properly considered from the outset — which can smooth the overall application process.
The Four Construction Activities Assessed
The IAQM methodology divides construction-related dust generation into four distinct activities, each assessed separately in terms of its emission magnitude and its potential risk to nearby receptors:
Demolition
The breaking up and removal of existing structures generates significant quantities of coarse and fine particulate matter, particularly from masonry, concrete, and older materials that may include legacy contaminants. The risk level depends on the size and condition of the structures, the proximity of receptors, and the demolition method proposed.
Earthworks
Bulk excavation, cutting, grading, and fill operations — particularly in dry conditions or on sites with loose, sandy, or silty soils — can generate dust over large areas. The risk assessment considers the duration of earthworks, the weather conditions typical for the time of year, and receptor proximity.
Construction
The construction phase covers activities such as cutting, grinding, mixing, and moving materials. Concrete cutting, block work, and dry mix activities are typically the highest-risk operations. The assessment evaluates the intensity and duration of construction activity and the types of materials involved.
Trackout
Mud and debris carried off site by construction vehicles and deposited on public roads creates a secondary source of dust as it dries. Trackout assessment considers the volume and type of vehicles leaving the site, the condition of the site access, and the character of nearby roads and receptors.
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How We Carry Out a CDRA — Step by Step
Our assessments follow the IAQM four-step process, and every report we produce is specific to the site and the proposed works — we don't use template reports that have simply had a name and address swapped in.
Step 1: Baseline Characterisation
We establish the background particulate matter (PM10) concentration for the site using DEFRA's national background mapping data. This tells us how much pollution is already present in the area and what additional loading sensitive receptors can reasonably absorb. We also map all sensitive receptors within the relevant study area — typically 350 metres for demolition and earthworks, 50 metres for trackout — and categorise them by receptor type and distance.
Step 2: Sensitivity Assessment
We combine the background PM10 concentration with the number and type of sensitive receptors to assign an area sensitivity rating of high, medium, or low. This reflects the pre-existing vulnerability of the surrounding area to dust impacts before any site activity begins.
Step 3: Source Magnitude Assessment
For each of the four activity types, we assess the potential dust emission magnitude based on the scale of the works, the materials involved, the site conditions, and the proposed construction programme. This is rated on a scale from large to small.
Step 4: Risk Matrix and Mitigation
Combining the area sensitivity with the source magnitude for each activity produces an overall dust risk rating. Where risk is rated as medium or high, specific mitigation measures are required. We specify these measures proportionately — not every site needs the most intensive controls, but the measures we specify are always sufficient for the risk level identified.
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Dust Risk Categories and What They Mean for Your Site
The IAQM framework produces one of three risk ratings for each activity:
Low Risk
Low-risk activities in low-sensitivity areas require only basic good practice controls — site tidiness, dampening of dusty materials, and sensible site management. No formal Dust Management Plan is required, though good practice notes should be included in the CDRA.
Medium Risk
Medium-risk scenarios require a defined set of mitigation measures and a brief Dust Management Plan setting out how they will be implemented and monitored. This is the most common outcome for urban residential developments.
High Risk
High-risk scenarios — typically large demolition or earthworks contracts in densely populated urban areas — require a comprehensive Dust Management Plan, a named Dust and Emissions Coordinator, real-time PM10 monitoring, and a clear complaint-response procedure. High-risk ratings are relatively uncommon for small to medium developments, but common for major regeneration schemes.
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Mitigation Measures: From Wheel Washes to Air Quality Monitoring
The mitigation measures we specify are drawn from the IAQM guidance and scaled to the risk level. For medium and high-risk activities, we typically require a combination of:
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Water suppression on active demolition and earthworks areas, with dedicated water bowser or sprinkler coverage.
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Enclosed or screened loading and unloading areas to contain dust at source.
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Wheel wash facilities at all site exits, with appropriate drainage and silt management.
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Sheeting or covering of all loads leaving the site.
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Restriction of dry sweeping on site — damp sweeping or vacuum extraction required.
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Speed limits on site haul roads to reduce vehicle-generated dust.
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Dust monitoring at site boundary locations — either visual screening or PM10 continuous monitoring, depending on risk level.
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Action levels tied to monitoring results, with a defined escalation procedure.
Where a site is particularly sensitive — for example, adjacent to a school or care home — we may also recommend proactive communication with occupants and a dedicated point of contact for complaints.
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Dust Management Plans — What They Include
A Dust Management Plan (DMP) is a standalone document, separate from the CDRA, that sets out the practical implementation of mitigation measures on site. It is the document that the site manager will actually use, so it needs to be clear, practical, and specific to the site layout and programme.
A typical DMP includes: site-specific dust risk map identifying high-risk zones; mitigation measures mapped to each construction phase; monitoring locations, frequencies, and equipment specifications; trigger levels for escalation; named responsible persons; and a complaint log procedure. Where required by the LPA, the DMP may need to be submitted and approved before works commence.
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CDRA for Demolition Projects
Demolition warrants particular attention in construction dust assessment because it generates the highest emission magnitudes of any construction activity — particularly where older masonry, concrete, or industrial structures are involved. Demolition of buildings pre-dating the 1980s may also raise concerns about asbestos-containing materials, which require separate assessment and licenced removal procedures under the Control of Asbestos Regulations 2012. Our CDRAs note this where relevant and flag the need for a pre-demolition asbestos survey if one hasn't already been commissioned.
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CDRA and Environmental Impact Assessment
For larger developments that require an Environmental Impact Assessment (EIA) under the Town and Country Planning (Environmental Impact Assessment) Regulations 2017, the construction dust risk assessment typically forms part of the Air Quality chapter of the Environmental Statement. We prepare EIA-compliant air quality assessments that cover both construction and operational phases, including CDRA content, to the level of detail required by the scoping opinion and the relevant guidelines.
Fees, Timescales, and What We Need from You
The cost of a CDRA depends on the scale and complexity of the proposed development and the sensitivity of the surrounding area. A straightforward single-phase residential conversion in a low-sensitivity area will be at the lower end of the range £550-£950. A major demolition and redevelopment in an AQMA with continuous monitoring requirements will be more involved.
We aim to provide a fee proposal within 24 hours of receiving the relevant site information, and most standard CDRAs are completed within five to seven working days. To get started, we typically need: the site address and red line boundary; a description of the proposed works and programme; any existing planning correspondence, including validation letters or pre-application advice; and a site location plan.
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Areas We Cover
We provide construction dust risk assessments for developments across Greater London, Kent, Essex, and Scotland. We work with developers, contractors, planning consultants, and architects — typically instructed either at pre-application stage or when a planning officer identifies a dust assessment requirement on a live application. Contact us to discuss your project.
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Get in Touch
If you need advice on whether an Construction Dust Risk Assessment is required for your site, or if you're ready to commission one, we're here to help. We work directly with architects, developers, planning consultants, and local authorities to deliver reports that support successful planning outcomes.
Get in touch to discuss your site and receive a quote.
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