Transcript Sample 1

New IAQM Guidance
Construction Dust Impacts
Claire Holman
17th 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)
Duncan Laxen, IAQM/BRE Meeting, 20 Jan 2011
Assessment Approaches (3)
Duncan Laxen, IAQM/BRE Meeting, 20 Jan 2011
PM10 impacts: London & SE
England
Fuller & Green, 2004
Fugitive Emissions: No of days exceeded 50 µg/m3
Year
No of sites
0
1
2-4
5-7
>7
1999
57
43
8
3
1
2
2000
68
51
12
3
2
1
2001
75
58
10
7
0
1
PM10 impacts: London & SE
England
Fuller & Green, 2004
Site
Period
No of days exceeded 50 µg/m3
Total measured
Fugitive emissions
Marylebone Road
14 July - 30
November 1999
84
20 (24)
Kensington & Chelsea
2
15 June - 8 December
1999
19
9
Crystal Palace
16 March 2000
1
1
Croydon 3
24-25 August 2000
2
2
Cardiff AURN Site
 5m from re-development of site
 Reported in AQEG, 2005
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!)
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
Mineral Planning Statement 2
High sensitivity
Hospitals and clinics
Medium Sensitivity
Schools
Retirement homes
Residential areas
Hi-tech industries
Food retailers
Painting and finishing
Food Processing
Low Sensitivity
Farms
Light and heavy industry
Glasshouses and nurseries
Horticultural land
Offices
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?
Outdoor storage
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.
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?
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
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
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
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.
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
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
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)
Construction Risk Category
Distance to Nearest Receptor (m)
1
Potential Dust Emission Class
Dust Soiling and PM10
Ecological
Large
Medium
Small
<20
-
High Risk Site
High Risk Site
Medium Risk Site
20 – 50
-
High Risk Site
Medium Risk Site
Low Risk Site
50 – 100
<20
Medium Risk Site
Medium Risk Site
Low Risk Site
100 – 200
20 – 40
Medium Risk Site
Low Risk Site
Negligible
200 – 350
40-100
Low Risk Site
Low Risk Site
Negligible
1
Based on distance from dust emitting activity
or, if not known, from site boundary
Example: Summary Risk Effects
Table - No Mitigation
Source
Dust soiling effects
Ecological effects
PM10 effects
Demolition
High Risk Site
None
Low Risk Site
Earthworks
Medium Risk Site
None
Negligible
Construction
Low Risk Site
None
Negligible
Trackout
Medium Risk Site
None
Negligible
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
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
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
Significance Criteria for each
Activity
Sensitivity of
surrounding
area
Risk of Site Giving Rise to Dust Effects
High
Medium
Low
No Mitigation
Very High
Substantial adverse
Moderate adverse
Moderate adverse
High
Moderate adverse
Moderate adverse
Slight adverse
Medium
Moderate adverse
Slight adverse
Negligible
Low
Slight Adverse
Negligible
Negligible
With Site-Specific Additional Mitigation
Very High
Slight adverse
Slight adverse
Negligible
High
Slight adverse
Negligible
Negligible
Medium
Negligible
Negligible
Negligible
Low
Negligible
Negligible
Negligible
Example: Summary Significance
Table
Dust soiling effects
Source
PM10 effects
Ecological effects
No mitigation
Demolition
Moderate adverse
None
Moderate adverse
Earthworks
Slight adverse
None
Negligible
Construction
Moderate adverse
None
Negligible
Trackout
Moderate adverse
None
Negligible
Moderate adverse
Overall significance
With mitigation
Demolition
Slight adverse
None
Slight adverse
Earthworks
Slight adverse
None
Negligible
Construction
Slight adverse
None
Negligible
None
Negligible
Trackout
Overall significance
Slight adverse
Four step approach
Working Group
Chair
Claire Holman, ENVIRON
Drafting sub group
Carl Hawkings, ADM Ltd
Claire Holman, ENVIRON
Duncan Laxen, Air Quality Consultants Ltd
Matt Stoaling, SLR Consulting
Other Members
Alaric Lester, TRL
Amanda Gair, Gair Consulting Ltd.
Anneliese Lithgow, Mott MacDonald
Daniel Marsh, Kings College London,
Deshni Nadar, London Borough of Tower Hamlets
Edward Haythornthwaite, City of London
Simon Cousins, Greater London Authority
Stuart Upton, BRE
Ad hoc member: Joanne Holbrook, Berrymans Lace Mawer
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
Version 2
 Review guidance in 2013
 Experience of using guidance will result in a
Version 2
 Feedback gratefully received