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New IAQM Guidance

New IAQM Guidance. Construction Dust Impacts Claire Holman 17 th November 2011. Content. Why do we need guidance? How it was developed Draft IAQM Guidance. Assessment Approaches (1). From Duncan Laxen, IAQM/BRE Meeting, 20 Jan 2011. Assessment Approaches (2).

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New IAQM Guidance

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  1. New IAQM Guidance Construction Dust Impacts Claire Holman 17th November 2011

  2. Content • Why do we need guidance? • How it was developed • Draft IAQM Guidance

  3. Assessment Approaches (1) From Duncan Laxen, IAQM/BRE Meeting, 20 Jan 2011

  4. Assessment Approaches (2) Duncan Laxen, IAQM/BRE Meeting, 20 Jan 2011

  5. Assessment Approaches (3) Duncan Laxen, IAQM/BRE Meeting, 20 Jan 2011

  6. PM10 impacts: London & SE England Fuller & Green, 2004

  7. PM10 impacts: London & SE England Fuller & Green, 2004

  8. Cardiff AURN Site • 5m from re-development of site • Reported in AQEG, 2005

  9. BRE Research • “Well controlled” demolition/construction site • Monitored for 18 months from 2001 to 2003 • Long term PM10 increased by ~2 µg/m3 close to site • Impacts <150m • Greatest impacts (>10 µg/m3 increase over period) from: • Demolition/removal of material • Piling, soil removal + infilling • Foundation works • (and Easter break!)

  10. Questions Raised • Do construction sites have proportionally greater impact today? • Transport PM emissions declined (but TEOM/FDMS issue) • Construction PM emissions declined? • GLA Best practice guidance 2006 • Has it reduced construction emissions? • What is the evidence? • Monitoring undertaken - data not systematically analysed or readily available Little robust scientific evidence of the distance over which impacts may occur

  11. Mineral Planning Statement 2 Mineral Planning Statement 2 After Ireland, M, 1992 20 years old. Still relevant? Hi-tech / food processing industries often filter the inlet air, so does this reduce its sensitivity?

  12. Annoyance or Nuisance? • Planning Policy Statement PSS23: • Statutory nuisance - is not intended to secure a high level of amenity but is a basic safeguarding standard intended to deal with excessive emissions. Nuisance does not equate to loss of amenity. • Significant loss of amenity will often occur at lower levels of emission than would constitute a statutory nuisance. It is therefore important for planning authorities to consider properly, loss of amenity from emissions in the planning process in its wider context and not just from the narrow perspective of statutory nuisance.

  13. Mitigation • Is there any need to assess the impacts when mitigation plays such a vital role in determining the effects? • Does mitigation mean there are no residual effects? • The guidance should determine the level of risk and the associated mitigation measures only? Or does it need to include the significance of the potential effects?

  14. IAQM Guidance • Consistency of approach • Lack of robust evidence • Every site is different • Professional judgement required - cannot be too prescriptive • Membership consultation –October • Review comments – November • Launch – November 17th • Web site – December 2011 • Examples on web site • www.iaqm.co.uk

  15. Screening Criteria Step 1 – Screening Criteria • An assessment will be normally be required where there are sensitive receptors within: • 350 m of the boundary of the site • 100 m of the route(s) used by construction vehicles on the public highway, up to 500 m from the site entrance(s) • Deliberately conservative

  16. Defining the Risk of Dust Effects Step 2 – Risk of Dust Effects • Define: • area surrounding the site • For each activity define: • potential dust emission class and • risk category • Assumes no mitigation

  17. Four Sources Considered • Demolition • Any activity involved with the removal of an existing structure (or structures). • Earthworks • The processes of soil-stripping, ground-levelling, excavation and landscaping. • Construction • Any activity involved with the provision of a new structure (or structures). • Track-out • The transport of dust and dirt from the site onto the public road network, where it may be deposited and then re-suspended by vehicles using the network.

  18. Risk Category • Scale of works defines the potential dust emission class • Potential dust emission class and distance of nearest receptor defines the risk category • Ecological and human receptors • Professional judgement (“qualified person”) • Assessment may use other criteria, but must be justified

  19. Potential Dust Emissions Class Example: Demolition • Large • Total building volume >50,000m3, potentially dusty construction material (e.g. concrete), demolition activities >20m above ground level • Medium • Total building volume 20,000m3 – 50,000m3, potentially dusty construction material, demolition activities 10-20m above ground level • Small • Total building volume <20,000m3, construction material with low potential for dust release (e.g. metal cladding or timber), demolition activities <20m above ground, demolition during wetter months

  20. Potential Dust Emissions Class Example: Construction • Large • Total building volume >100,000m3, piling, on site concrete batching; sandblasting • Medium • Total building volume 25,000m3 – 100,000m3, piling, on site concrete batching • Small • Total building volume <25,000m3, construction material with low potential for dust release (e.g. metal cladding or timber)

  21. Construction Risk Category 1 Based on distance from dust emitting activity or, if not known, from site boundary

  22. Example: Summary Risk Effects Table - No Mitigation

  23. Mitigation Step 3 – Mitigation • Site specific, to take account of local conditions • To be based on GLA mitigation • Large • Medium • Low • Separate mitigation for the four sources

  24. Effects & Significance Step 4 – Define Effects & Significant • Depends on: • the potential risks set out within the risk category table • the duration for which the sources might be close to the sensitive receptors • the proximity and number of sensitive receptors • Presence of natural shelters, such as trees, to reduce the risk of wind-blown dust • the sensitivity of the receptor(s) • Background PM10 concentrations

  25. Example: Proximity & Number of Receptors • Proximity bands • Less than 20m • 20 to 40m/50m • 40m/50 to 100m • More than 100m • Number of human receptors (dwellings): • Less than 10 • 10 -100 • 100 - 500 • More than 500

  26. Significance Criteria for each Activity

  27. Example: Summary Significance Table

  28. Four step approach

  29. Working Group

  30. Thanks • Fiona Prismall/Jon Pullen, RPS • Katherine Hauser, Golders Associates UK Ltd • Michelle Hackman, Aecom • Graham Harker/Denise Welch, Peter Brett Associates • John Lamb, SEPA • Rachel Brooks, Dundee Council • Kyri Eleftheriou-Vau, Royal Borough Kensington & Chelsea • And Many Others

  31. Version 2 • Review guidance in 2013 • Experience of using guidance will result in a Version 2 • Feedback gratefully received

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