20.1CONSTRUCTION PHASE METHODOLOGY AND ASSESSMENT 1.
The following section outlines criteria developed by the Institute of Air Quality Management (IAQM, 2014) for the assessment of air quality impacts arising from construction activities. The assessment procedure is divided into five steps and is summarised below:
20.1.1 Step 1: Screening the need for a Detailed Assessment 2.
An assessment will normally be required where there are human receptors within 350m of the site boundary and/or within 50m of the route(s) used by construction vehicles on the public highway, up to 500m from the site entrance(s). Ecological receptors within 50m of the site boundary or within 50m of the route(s) used by construction vehicles on the public highway, up to 500m from the site entrance(s), are also identified at this stage. An ecological receptor refers to any sensitive habitat affected by dust soiling. For locations with a statutory designation, such as a Site of Specific Scientific Interest (SSSI), Special Area of Conservation (SACs) and Special Protection Areas (SPAs), consideration should be given as to whether the particular site is sensitive to dust. Some non-statutory sites may also be considered if appropriate.
Where the need for a more detailed assessment is screened out, it can be concluded that the level of risk is ‘negligible’.
There are a number of ecological receptors within 50m of the site boundary and there are human receptors within 350m. A Detailed Assessment is therefore required.
20.1.2 Step 2: Assess the Risk of Dust Impacts 5.
A site is allocated to a risk category on the basis of the scale and nature of the works (Step 2A) and the sensitivity of the area to dust impacts (Step 2B). These two factors are combined in Step 2C to determine the risk of dust impacts before the implementation of mitigation measures. The assigned risk categories may be different for each of the four construction activities outlined by the IAQM (demolition, construction, earthworks and trackout).
The site can also be divided into zones, for example on a large site where there are differing distances to the nearest receptors.
20.1.3 Step 2A: Define the Potential Dust Emission Magnitude 7.
The IAQM guidance recommends that the dust emission magnitude is determined for earthworks, construction and trackout. The dust emission magnitude is based on the scale of the anticipated works. Table A1 describes the potential dust emission
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