Updated IAQM Construction Guidance: Implications for Developers

The Institute of Air Quality Management (IAQM), the professional body for air quality consultants in the UK, recently updated their Guidance on the assessment of dust from demolition and construction. This guidance is referred to in the majority of air quality assessments in the UK, it explains how construction dust risk assessments are undertaken and what constitutes an appropriate level of dust mitigation.  The update will change the assessed dust risk of some construction projects, influencing the type of dust mitigation and monitoring developers and contractors will be required to employ, to adhere to best practice.

For those involved in planning applications and building works, it is crucial to understand the implications of these revisions. In this short article, we will delve into the key changes and their potential impact on developers and contractors.

The most significant amendment in the updated IAQM guidance is the redefinition of the ‘dust emission magnitude’ categories for demolition, earthworks, construction, and trackout. These changes are aimed at providing a more accurate assessment of dust emissions. Here is a comparison of the changes:

Phase	2014 Guidance	2023 Guidance
Demolition	Large: Total building volume >50,000 m3 Medium: Total building volume 20,000 m3 – 50,000 m3 Small: Total building volume <20,000 m3	Large: Total building volume >75,000 m3 Medium: Total building volume 12,000 m3 – 75,000 m3 Small: Total building volume <12,000 m3
Earthworks	Large: Total site area >10,000 m2, Medium: Total site area 2,500 m2 – 10,000 m2 Small: Total site area <2 ,500 m2	Large: Total site area >110,000 m2 Medium: Total site area 18,000 m2 – 110,000 m2 Small: Total site area <18,000 m2
Construction	Large: Total building volume >100, 000 m3 Medium: Total building volume 25,000 m3 – 100,00m3 Small: Total building volume <25,000 m3	Large: Total building volume >75,000 m3 Medium: Total building volume 12,000 m3 – 75,000 m3 Small: Total building volume <12,000 m3
Trackout	Large: >50 HDV (>3.5t) outward movements in any one day Medium: 10-50 HDV (>3.5t) outward movements in any one day Small: <10 HDV (>3.5t) outward movements in any one day	Large: >50 HDV (>3.5t) outward movements in any one day Medium: 20-50 HDV (>3.5t) outward movements in any one day Small: <20 HDV (>3.5t) outward movements in any one day

To illustrate the practical implications of the revised guidance, let’s consider an example: the demolition of a 15,000 m³ building in central London on a 1-hectare plot of land. Under the previous guidelines, this would have resulted in a Small dust emission magnitude for demolition and a Large emission magnitude for earthworks. However, the 2023 guidance, acknowledging the greater concern posed by demolition activities, classifies the dust magnitude associated with demolition as Medium and earthworks as Small.

These shifts may lead to a higher proportion of developments being categorized as presenting a Medium risk of dust soiling. In London, and other urban areas, dust management plans (either standalone or a part of a Construction Environmental Management Plan) are often required for development that present a Medium risk. Medium risk projects are also normally required to carry out continuous particulate monitoring (PM₁₀/ PM_2.5). As councils can request baseline monitoring of up to 3 months prior to any construction work taking place, these changes could have significant impacts on the timelines of some projects.

The updated IAQM guidance also provides clarity on the level of detail required in dust risk assessments for different planning application types. For Outline Permission applications, where limited information regarding construction methods may be available, an initial screening dust assessment is recommended. At a later planning stage, whether for full permission or associated with planning conditions, the updated guidance dictates that a detailed assessment should be conducted, considering the development’s scale and precise distances from dust sources to receptors.

The recent guidance update reflects the latest knowledge about the health effects of PM_2.5. These ultra-fine particles can enter our bloodstream and have a significant impact on our health. The revisions in the guidance were made to ensure that these health risks are addressed comprehensively, acknowledging the evolving understanding of PM_2.5 and its implications on public health.

If you would like to discuss how changes to the IAQM’s Guidance on the assessment of dust from demolition and construction may impact your construction project, please do not hesitate to get in touch.