6. Air quality South London ERF Viridor Chapter 6: Air quality
6 Air quality
Introduction 6.1 This chapter presents the results of an assessment carried out by RWDI and Gair Consulting Ltd of the impacts on local air quality arising from the construction and operation of the proposed Energy Recovery Facility (ERF) at the proposed development site.
6.2 The proposed development will have potential implications for local air quality through emission to atmosphere principally from the following sources:
• Construction activities, including vehicle movements • Vehicle movements associated with the delivery of waste and the removal of ash • The flue gases emitted through the chimney stacks
6.3 In comparison, all other possible sources associated with the proposed development are minor and unlikely to represent a significant impact, although their potential to release pollutants or odours is considered in this report.
6.4 Key data sources referred to in carrying out the air quality assessment include those set out in table 6.1.
Directive 2000/76/EC of the European Parliament and of the Council of 4 December 2000 on the incineration of waste Croydon Council (2007) Standards and Requirements for Improving Local Air Quality - Interim Policy Guidance Directive 2008/50/ECof the European Parliament and of the Council of 21 May 2008 on ambient air quality and cleaner air for Europe Guidelines for Halogen and Hydrogen Halides in Ambient Air for Protecting Human Health Against Acute Irritancy Effects, EPAQS (February 2006) Addendum to Guidelines for Halogen and Hydrogen Halides in Ambient Air, EPAQS (May 2009) Air Quality Standards Regulations 2010 (SI 2010/2001) Environmental Protection The Air Quality Strategy for England, Scotland, Wales and Northern Ireland Directive 2008/50/EC World Health Organisation WHO, Air quality Guidelines 2000 Guidelines for Metals and Metalloids in Ambient Air for the Protection of Human Health, EPAQS (May 2009) Environment Agency H1 adopted from the UN Economic and Social Council, Executive Body for the Convention on Long-Range Transboundary Air Pollution Environment Agency Horizontal Guidance Note H1, Annex (f) -Air emissions, Version 2.2, August 2010 IAQM (2010) Development Control: Planning for Air Quality (2010 Update) Targeted Application of Calcium Magnesium Acetate (CMA) Pilot Study Monitoring Report, URS Corp Ltd for Transport for London, July 2011 http://laqm.defra.gov.uk/review-and-assessment/tools/background-maps.html UK Soil and Herbage Pollutant Survey, SHS Report 10 Environmental Concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in UK soil and herbage, June 2007 Alloway BJ (1995) Heavy Metals in Soils published by Blackie Academic
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
IAQM (2012) Guidance on the Assessment of Impacts of Construction on Air Quality and the Determination of their Significance v1.1 Environment Agency (2011) Guidance to Applicants on Impact Assessment for Group 3 Metals Stack Releases- V2 June 2011 Defra (2011) Emissions from Waste Management Facilities: Frameworks for Assessment of Data Quality and Research Needs – WR 0608 (prepared by Environmental Resources Management Ltd) Table 6.1: Data sources
Legislation and policy
National policy 6.5 National planning policy, in the form of the National Planning Policy Framework, has relatively little to say about air quality directly. Paragraph 124 notes that compliance with air quality limit values and objectives should be achieved and that the presence of Air Quality Management Areas (AQMAs) should be accounted for. Reference is made to new development in AQMAs being consistent with local action plans for air quality.
6.6 AQMAs are a product of the 1995 Environment Act Part IV, which introduced the concept of Local Air Quality Management (LAQM). This has required local authorities to measure air quality and assess air quality in relation to national air quality objectives. In places where compliance is not achieved, or where compliance is threatened, an action plan must be prepared that defines measures to improve air quality.
6.7 In 1997, the Government adopted its first Air Quality Strategy, setting out an analysis of existing air quality for eight key pollutants and setting out a series of measures to improve concentrations of these pollutants in the future. The Strategy has been successively updated, with the most recent version being published in 2007. No specific reference is made to waste management facilities in this document and its references to planning policy have now been overtaken by the introduction of the National Planning Policy Framework.
National and European legislation 6.8 Ambient air quality is regulated through European Directives that set limit values on the concentrations of key pollutants. EU limit values have legal force and are intended to apply at all locations where public exposure might occur. The air quality objectives for England and Wales, as set out in the Air Quality Strategy, and are very similar to the EU limit values in most cases, in terms of their threshold concentrations.
6.9 Emissions of some pollutants are regulated at the national level through a number of European Union Directives. The National Emissions Ceilings Directive sets the UK a limit for emission of oxides of nitrogen (NOx), sulphur dioxide (SO2), ammonia (NH3) and volatile organic compounds (VOCs).
6.10 The UK is a signatory to the Stockholm Convention on Persistent Organic Pollutants (POPs), first adopted in 2001 and entering into force in 2004. POPs are substances that are found in pesticides, industrial chemicals, including poly chlorinated biphenyls (PCBs), and unintentional by products, which
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
include dioxins and furans (known more properly as poly chlorinated dibenzo- p-dioxins and poly chlorinated dibenzofurans). The Convention seeks to protect the environment from the exposure to POPs by restricting, and ultimately eliminating, their production, use, trade, release and storage.
6.11 Control of industrial emissions is governed by the Industrial Emissions Directive (2010/75/EU), which has yet to be transposed into UK law. This new directive includes seven existing directives, one of which is on Integrated Pollution Prevention and Control (IPPC), which forms the basis for the regulation of industrial facilities, such as the ERF. The IPPC Directive has been implemented in England and Wales through a permitting system, operated by the Environment Agency. In order for an installation to operate legally, the operator must apply for and be granted a permit.
6.12 An application to the Environment Agency for a permit to operate the South London ERF will be made at approximately the same time as planning permission is sought. This allows the Environment Agency to engage fully with Viridor on the ERF technology.
6.13 The design and operation of all new waste incineration facilities must ensure compliance with emission limit values (ELVs) set out in the Waste Incineration Directive (WID) recently incorporated into the Industrial Emissions Directive. The Waste Incineration Directive (2000/76/EC) aims to reduce the impact of waste incineration on human health and the environment. The directive applies to incineration and co-incineration plants which burn waste as defined in the Waste Framework Directive. The WID was transposed into UK law via the Waste Incineration (England and Wales) Regulations 2002 (SI 2002 No, 2980), which came into force on 28 December 2002. The WID ELVs applicable to the proposed ERF are summarised in table 6.2.
30-minute mean Substance Daily mean 100th percentile 97th percentile Particles 10 30 10 Nitrogen Dioxide 200 400 200 Sulphur Dioxide 50 200 50 Carbon Monoxide 50 100 (b) 150 (c) Hydrogen Fluoride 1 4 2 Hydrogen Chloride 10 60 10 Total Organic Carbon (TOC) 10 20 10 Group I metals - Cd and Tl (d) 0.05 Group II metals - Hg (d) 0.05 Group II metals - Sb, As, Pb, Cr, Co, 0.5 Cu, Mn, Ni and V (d) Dioxins and Furans 0.1 ng I-TEQ m-3 Table 6.2: Waste Incineration Directive Emission Limit Values (mg Nm-3) (a) (a) Units are mg Nm-3 (273K, dry and 11% O2) unless stated otherwise (b) 100th percentile of half-hourly average concentrations in any 24-hour period (c) 95th percentile of ten-minute average CO concentrations (d) Average over a sample period between 30 minutes and 8-hours
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
Greater London and London Borough policies 6.14 Through the Mayor’s office, London is able to promote distinctive policies on land use planning and air quality that may enhance the objectives of national and European policies.
6.15 The most recent version of the Mayor’s Air Quality Strategy was published in December 2010. Much of the strategy, and the policies it promotes, is focused on road transport emissions, since this sector contributes most to the air quality problems in London. Waste management does not feature strongly in the strategy, although recognition is given to the fact that some waste management sites in the capital have been shown to be locations where PM10 concentrations are elevated, sometimes through the re-suspension of street dust by vehicles. The policy adopted is to deploy targeted measures at such locations and this has resulted in dust suppressant being used along some roads where PM10 concentrations are a problem.
6.16 The London Plan, published in July 2011, sets out the planning policies for the spatial development of London. With regard to air quality, the plan states that development proposals should:
• Minimise increased exposure to existing poor air quality and make provision to address local problems of air quality • Reduce emissions for the demolition and construction of buildings following the best practice guidance in the GLA and London Councils • Be at least ‘air quality neutral’ and not lead to further deterioration of existing poor air quality (such as areas designated as AQMAs)
6.17 These policies are aimed principally at commercial and residential development, where the dominant concerns relate to increased traffic movements, onsite energy generation with biomass boilers and the introduction of new residents into areas of poor air quality.
6.18 The boroughs of Sutton, Croydon and Merton have all responded to the requirements of LAQM and have produced action plans to improve air quality in those parts of the boroughs where AQMAs have been declared. The action plans were first devised and published in 2003 -– 2004 and progress on their implementation has been reported in 2008 – 2010. Most of the measures relate to transport, consistent with the causes of non-compliance with air quality standards.
6.19 London councils have produced policy guidance on the improvement of local air quality, part of which is concerned with the assessment of air quality for planning applications. Croydon Council actively promotes this guidance.
Methodology 6.20 This section describes the pollutants considered as part of the assessment, the regulations governing ambient air quality, along with the methods used to assess the potential impacts of the proposals and the criteria adopted for defining the significance of impacts.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
Ambient air quality 6.21 The pollutants considered in the assessment include primarily those that are set out in the Waste Incineration Directive:
• Fine particles (PM10) • The oxides of nitrogen (NOx) • Sulphur dioxide (SO2) • Carbon monoxide (CO) • Hydrogen fluoride (HF) • Hydrogen chloride (HCl) • Total organic carbon (TOC) as benzene • Dioxins and furans (PCDD/Fs) • Trace metals: cadmium (Cd), thallium (Tl), mercury (Hg), antimony (Sb), arsenic (As), lead (Pb), chromium (Cr), cobalt (Co), copper (Cu), manganese (Mn), nickel (Ni) and vanadium (V).
6.22 Emissions of ammonia (NH3), PM2.5 (particles of aerodynamic diameter ≤ 2.5µm) and polycyclic aromatic hydrocarbons (PAHs) are also considered, for the following reasons:
• NH3 is of interest in relation to impacts on habitats, directly and as a component of acid and nutrient nitrogen deposition • PM2.5 has recently become an increasingly prominent air pollutant of interest, with increasing evidence indicating that PM2.5 is associated with impacts to health. It is now subject to a statutory air quality standard in the UK, following implementation of the European Union’s Ambient Air Quality Directive) • PAHs have recently become an increasingly prominent air pollutant of interest and one of the key PAH species, benzo[a]pyrene, is subject to a statutory air quality standard in the UK
6.23 In addition, consideration is made of NO2, PM10 and PM2.5 in relation to emissions from development related traffic and emissions of odour during operation of the proposed ERF.
6.24 In relation to impacts on sensitive habitat sites, the potential impacts associated with emissions of NH3, NOx and SO2 have been assessed both through impacts directly to air quality and through deposition of acid and nutrient nitrogen.
6.25 The air quality and health technical appendix (Technical Appendix B) sets out in detail the relevant objective / limit values / critical levels, as set out in the Air Quality Strategy, European directives, Environment Agency guidance applicable to each pollutant assessed.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
Assessment methodology Baseline Air quality 6.26 Automatic monitoring of ambient pollutant concentrations is carried out by LBS and London Borough of Croydon at a number of locations within 5 km of the proposed ERF. A summary of the sites closest to the proposed ERF is presented in table 6.3. London Borough of Merton also operates two roadside automatic monitoring stations around 4 km north west of Beddington Lane. These sites, however, were installed relatively recently and ratified data for a full year are not currently available for either site.
6.27 All of the sites listed in table 6.3 are part of the London Air Quality Network (LAQN) and therefore the data are subject to high levels of quality assurance and control. The location of the monitoring sites with respect to the proposed ERF is presented in figure 6.1.
Monitoring site Site grid reference Site type Pollutants measured
1. Croydon- Norbury 530626, 169707 Kerbside NO2
2. Croydon - Thornton Heath 532336, 168934 Suburban NO2, PM10 (TEOM)
3. Croydon - George Street 532583, 165636 Roadside NO2, PM10 (TEOM)
4. Croydon - Purley Way 531123, 164299 Roadside NO2
5. Sutton - Wallington 528925, 163804 Kerbside NO2, PM10 (TEOM)
6. Sutton - Carshalton 527776, 164513 Suburban NO2
7. Sutton - Therapia Lane 529780, 166850 Industrial NO2, PM10 (TEOM)
8. Sutton - Beddington Lane 529400, 167224 Industrial NO2, PM10 (TEOM) Table 6.3: LAQN automatic monitoring stations close to the proposed ERF 6.28 Additional automatic monitoring of ambient concentrations of nitrogen oxides (NOx), particulate matter (as PM10), ammonia (NH3), sulphur dioxide (SO2), nitrogen oxides (NOx), carbon monoxide (CO), benzene, hydrogen sulphide (H2S) and 1,3-butadiene was undertaken by Mouchel at Beddington Lane for a seven month period from May to November 2011. The data were compared with concentrations measured at the nearby LAQN monitoring stations and are believed to be of good quality.
6.29 Monitoring of ambient NO2 concentrations is carried out by London boroughs of Sutton, Merton and Croydon via a network of passive diffusion tubes. Unfortunately, none of the local authority monitoring sites is sufficiently close to the proposed site to be of relevance to the assessment.
6.30 Passive diffusion tube monitoring of NO2, HCl, HF, SO2 and VOCs at a number of locations (see table 6.4) in the Beddington Lane area was carried out for a period of approximately six months in 2011 by Mouchel. The location of the tubes is presented in figure 6.2.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
Site ID Pollutants measured
Bed M1 NO2, SO2, HCl, HF, VOCs
Bed M2 NO2
Bed M3 NO2
Bed M4 NO2 Bed M5 NO2
Bed M6 NO2, SO2, HCl, HF, VOCs Bed M7 NO2
Bed M8 NO2, SO2, HCl, HF, VOCs Bed M9 NO2 Bed M10 NO2
Bed M11 NO2, SO2, HCl, HF, VOCs
Bed M12 NO2, SO2, HCl, HF, VOCs
Bed M13 NO2, SO2, HCl, HF, VOCs
Bed M14 NO2
Bed M15 NO2
Bed M16 NO2
Bed M17 NO2
Bed M18 NO2
Bed M19 NO2 Table 6.4: Passive diffusion tubes in Beddington 6.31 A BAM automatic analyser was installed at the rear of Archbishop Lanfranc School on Mitcham Road in March 2012. This instrument was fitted with a PM2.5 sampling head and measures concentrations of this pollutant continuously. Insufficient data have been collected at the time of writing to report a credible long term average mean concentration.
Soil pollution 6.32 The historical legacy of air pollution at a location can be examined through the measurement of persistent pollutants in the upper layer of undisturbed soil. The presence of metals and persistent organic pollutants such as dioxins is also of relevance in the context of human exposure to such pollutants via the food chain. For these reasons samples of soil have been taken at locations around the development site, in order to quantify the existing concentrations and provide a baseline against which the accumulated future deposition from the ERF can be compared. RWDI took 1 kg samples of soil at each of five locations, as shown in figure 6.3 and described in table 6.5.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
Site Description and other relevant Grid reference Site name ID information S1 529006E 165441N Beddington Park Parkland area, near to sports pitches Recreational area, adjacent to rugby S2 527599E 166926N Poulter Park pitch. Housing on the park boundary. Mitcham Common land, used for recreation. S3 528915E 168113N Common Samples taken on hill top. Suburban area, with samples taken from a grassed area with housing S4 530233E 168410N Pollards Hill nearby and the youth centre. About 50 m from South Lodge Avenue. Public park. Surrounded by housing S5 531472E 165639N Wandle Park and with power station about 200 m away Table 6.5: Details of soil sampling sites 6.33 The samples were then sent to Scientific Analysis Laboratories Ltd (SAL), where they were analysed for a selected number of metals, dioxins and furans, dioxin-like poly chlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons.
Construction 6.34 Any form of demolition or construction activity has the potential to generate dust emissions and thereby cause annoyance to people in the vicinity of the site. The dust may also contribute to local concentrations of PM10. Assessing the likelihood and magnitude of such impacts is not straightforward, mainly because it is not possible to quantify the amount of dust emitted and therefore provide a quantitative estimate of the impact in terms of an increase in deposition rate or airborne concentration.
6.35 The Institute of Air Quality Management (IAQM) has recently produced guidance on the assessment of construction on air quality and this guidance forms the basis of the approach taken, and methods adopted for this assessment. The guidance advocates the use of a risk based approach that seeks to identify the scale of the construction activity, the distance to a receptor and the sensitivity of that receptor to air quality impacts. This approach is broadly followed in this assessment. See the following section on significance criteria for further details.
Vehicle emissions 6.36 ADMS-Roads (Version 3.1) has been used to assess the air quality impact arising from vehicles associated with the construction and operational phases of the proposed development. ADMS-Roads simulates the dispersion in the atmosphere of pollutants released from industrial and road traffic sources in urban areas. The model simulates the dispersion of emissions using point, line, area and volume source models.
6.37 The model has been used to predict the incremental impact of emissions of NO2 and PM10 from road traffic associated with the proposed development for
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
2011 baseline flows and the following scenarios (with and without development traffic):
• 2015 – Peak construction flows and landfill traffic • 2017 – Operational ERF flows and landfill restoration traffic • 2023 – Operational ERF flows (and recycling)
6.38 In order to assess the cumulative impact of emissions from the ERF stack and road traffic, the sensitive receptors used in the human health impact assessment have been included in the ADMS-Roads model. In addition, a number of receptors on Beddington Lane have been included which represent residential properties closest to the road (see the air quality technical appendix for details).
6.39 A summary of the 2011 baseline and 2015, 2017 and 2023 annual average daily traffic (AADT) and development flows on the local road network is presented in the air quality technical appendix. The development flows used here for modeling are an overestimate of the current best estimate by about 3% for 2023 and by 10% for 2015. The baseline flows are derived from an automatic traffic count survey carried out to support the Transport Assessment.
6.40 The development is expected to be associated with a traffic flow of 666 two way vehicle movements per day in 2023, when the site is fully operational; lower than the traffic flow associated with current landfill operations at the site (732).
6.41 The vast majority of the traffic associated with the ERF plant will be HGVs. This is also the case for the existing landfill traffic. The proposed ERF will not significantly affect the number of HGVs on the local road network compared with the existing levels.
6.42 The average vehicular speeds on the identified road links is not expected to change significantly as a result of traffic associated with the ERF. Vehicle speeds for the road links have been derived from the ATC data.
6.43 The ADMS-Roads model has been run using hourly sequential meteorological data from Gatwick Airport for 2011. This year was identified as producing the highest ground-level pollutant concentrations in the dispersion modelling assessment of emissions from the ERF and has therefore been chosen for consistency.
Stack emissions 6.44 The largest source of emissions to atmosphere will be the gases emitted to atmosphere through the two main chimney stacks. These gases will leave the chimney in a plume that subsequently disperses in the atmosphere and dilutes the concentrations of the pollutants it contains. The physical processes that govern this dispersion process can be simulated with a dispersion model, leading to the quantification of impacts in terms of airborne concentrations at ground level and deposition rates to the underlying surface.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
6.45 The primary dispersion model used in this assessment was ADMS 4, a well known model and one whose use is recognised by the Environment Agency, amongst others. The model requires inputs for:
• Meteorological conditions hour by hour • Terrain • Significant building dimensions • Emissions
6.46 Further details on these inputs are set out in the air quality technical appendix.
6.47 A modelling exercise was completed using preliminary emission data in order to derive a suitable stack height. Model runs were carried out using stack heights in the range 60 m to 100 m, at 5 m intervals. The results were expressed in terms of the annual mean concentrations of NO2, at the point of maximum impact. The results are summarised in the air quality technical appendix and demonstrate that a stack height of 85m is best.
6.48 The dispersion modelling was also used to consider the potential impacts on local habitat receptors, and each site of conservation importance identified in the baseline was assigned a critical level for the airborne concentration of either NOx, SO2, hydrogen fluoride or ammonia, and a critical load for acid or nutrient nitrogen deposition.
Significance criteria 6.49 Significance criteria in air quality assessments have not been in common use or widely agreed until quite recently, when the Institute of Air Quality Management and Environmental Protection UK produced some guidance on the subject (see table 6.1). This advice has been used as the basis for the criteria adopted here and adapted such that it is consistent with the significance criteria used in some of the other sections of the ES.
6.50 The first step is to describe the magnitude of the impact of a given pollutant, set out below in table 6.6.
Magnitude of change Annual mean concentration change (PC) Large Increase or decrease > 10% Medium Increase or decrease 5- 10% Small Increase or decrease 1 -5 % Imperceptible Increase or decrease < 1% Table 6.6: Magnitude of change descriptors 6.51 The change in air quality is then compared with the existing air quality and the relevant air quality standard or assessment criterion for each pollutant, to determine the degree of effect (negligible, slight, moderate or substantial) and from this ascribe significance. An effect is either not significant or significant; these aspects are set out below in table 6.7, assuming that the impact is adverse.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
Absolute value Magnitude of PC change (PEC) Imperceptible Small Medium Large PEC above AQS Negligible Slight Moderate Substantial with scheme Not significant Not significant Significant Significant PEC just below Negligible Negligible Moderate Moderate AQS with scheme Not significant Not significant Significant Significant PEC below AQS Negligible Negligible Slight Slight with scheme (at Not significant Not significant Not significant Not significant 75%-90% of AQS) PEC well below Negligible Negligible Negligible Slight AQS with scheme Not significant Not significant Not significant Not significant (at < 75% of AQS) Table 6.7: Assessing the degree of effect and significance 6.52 Thus, on the basis of these criteria, the increase in concentration or deposition rate of a pollutant has to be 5% or greater of the relevant assessment criterion for the impact to be described as ‘significant’. This is less stringent than the initial Environment Agency (EA) test to determine whether an impact is definitively ‘not significant’, where the test is 1% of the assessment criterion for long term average concentrations (but 10% for short term concentrations). However, the EA test then goes on to examine the impact relative to the PEC and if the PEC is less than 70% of the criterion, then the impact is deemed to be not significant. When the full EA test is considered, the scheme used for this air quality assessment is therefore very similar to the criterion used in environmental permitting and set out in Horizontal Guidance Note H1.
6.53 The EA criterion for significance has been adopted in this assessment for the specific case of habitats, since the EA guidance on the subject is the only one available and is recognised as such.
Baseline
Local authority review and assessment 6.54 Local authorities are required to periodically review and assess the current and future quality of air in their areas. Where it is determined that an air quality objective is not likely to be met within the relevant time period, the authority must designate an AQMA and produce a local action plan.
6.55 The early stages of the review and assessment process carried out by LBS highlighted elevated concentrations of NO2 and PM10 arising from road traffic in congested areas. Consequently, an AQMA for these pollutants was declared in March 2001 along the majority of the main roads in the borough. The AQMA was extended in 2004 to include two additional roads (including Beddington Lane) on the basis of measured exceedences of the air quality objectives.
6.56 The proposed ERF is around 800 m south and 500 m west of the boundaries with the London boroughs of Merton and Croydon respectively. Both
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
councils have declared borough-wide AQMAs for NO2 (Merton Council’s AQMA is also for PM10).
6.57 The LBS is predominantly residential, but with two main industrial areas -; Beddington in the north east of the borough and a smaller area in West Sutton. The Beddington Lane industrial area comprises a variety of light and heavy industrial units, including a number of waste management facilities. Emissions from these installations are believed to be a significant source of airborne PM10. Local monitoring data shows that concentrations of PM10 in the area are elevated, but the air quality objectives are not currently being exceeded. An AQMA for NO2 was declared in 2010 to limit further deterioration of air quality as a result of future development in the area.
6.58 The Beddington Lane AQMA extends from the boundary with London Borough of Merton in the north and borough of Croydon in the east. To the south, it extends down to Richmond Road and along the northern edge of Beddington Park. The western boundary extends to London Road and captures the whole of the Beddington Farmlands Landfill Site and sludge lagoons. The boundary of the Beddington Lane AQMA is illustrated in figure 6.4.
6.59 Beddington Lane may also be included in the Mayor of London’s Dust Suppression Trial. This involves spraying roads with a biodegradable saline solution, which binds particulate matter to the carriageway, preventing resuspension. Trials on Victoria Embankment and Marylebone Road showed that the airborne particle concentration was reduced by around 10% over a 24 -hour period.
Ambient air quality
Concentrations of fine particles (PM10 and PM2.5)
6.60 A summary of concentrations of PM10 (gravimetric equivalent) measured at LAQN monitoring sites from 2009 to 2011 is presented in table 6.8.
Number of 24 hour means Annual mean (µg m-3) Monitoring Site > 50 µg m-3 2009 2010 2011 2009 2010 2011 2. Croydon- Thornton Heath - (a) 20 21 - (a) 2 10 3. Croydon - George Street 24 - (a) 23 14 - (a) 15 5. Sutton - Wallington 26 25 - (a) 6 5 - (a) 7. Sutton - Therapia Lane - (b) - (b) 27 - (b) - (b) 20 8. Sutton - Beddington Lane 29 29 28 17 17 21 Air Quality Objective 40 35
Table 6.8: LAQN measured PM10 concentrations (2009 – 2011) Data capture below 90% Site not operational
6.61 Measured annual mean PM10 concentrations are well within the annual mean air quality objective of 40 µg m-3 at all of the LAQN sites. The highest annual mean concentration over the past three years was measured at Beddington Lane at 29 µg m-3, 73% of the objective. The number of exceedences of the
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
24-hour mean objective was within the 35 allowed at all sites. Again, the highest 24-hour means were measured at the two sites within the Beddington Lane industrial area.
6.62 PM10 concentrations have also been measured by Mouchel close to the site of the proposed ERF from 23rd May to 30th November 2011. During this period -3 the mean PM10 concentration was 34.8 µg m , which compared well with the LAQN monitoring data over the same period.
6.63 For comparison, ambient background concentrations of PM10 and PM2.5 for 2011 have been obtained from the Defra UK Background Air Pollution Maps. The mapped PM10 and PM2.5 concentrations for the area surrounding the proposed ERF are presented as contour plots in the air quality technical appendix. The mapped background PM10 concentrations are in reasonable agreement with concentrations measured at the suburban monitoring site at Thornton Heath, Croydon. At Beddington Lane, the mapped background -3 PM10 concentration is around 18 µg m , which suggests that local sources contribute up to 10 µg m-3 of the total annual mean concentration at this location.
6.64 For the purposes of this assessment it is appropriate to use a concentration of PM10 that is representative of urban background exposure. The Therapia Lane and Beddington Lane monitoring sites are located within or on the edge of the Beddington Lane industrial area and will not necessarily be representative of public exposure. Therefore, for the purposes of the assessment the annual mean PM10 concentration for public exposure is taken as the mean of the 2011 concentrations measured at the four monitoring locations, 25 µg m -3.
6.65 Until information on background PM2.5 concentrations over an extended period becomes available, it is assumed that the baseline PM2.5 concentration is 55% higher than the mapped background (as for PM10) at approximately 19 µg m-3, 76% of the EU limit value of 25 µg m-3.
Concentrations of nitrogen dioxide (NO2)
6.66 A summary of concentrations of nitrogen dioxide (NO2) measured at LAQN monitoring sites from 2009 to 2011 is presented in table 6.9.
Number of 1 Hour means Monitoring site Annual mean (µg m-3) > 200 µg m-3 2009 2010 2011 2009 2010 2011 1. Croydon- Norbury 66 76 61 11 7 22 3. Croydon - George Street 52 52 - (a) 0 0 - (a) 4. Croydon - Purley Way 44 - (a) - (a) 0 - (a) - (a) 5. Sutton - Wallington 79 73 - (a) 197 70 38 6. Sutton - Carshalton 31 31 26 0 0 0 7. Sutton - Therapia Lane - (b) - (b) - (a) - (b) - (b) - (a) 8. Sutton - Beddington Lane 42 - (a) 37 1 - (a) 0 Air Quality Objective 40 18
Table 6.9: LAQN measured NO2 concentrations (2009 – 2011) Data capture below 90% Site not operational
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
6.67 There are widespread exceedences of the annual mean NO2 objectives at the majority of the LAQN monitoring sites identified in table 6.3, which is not surprising, since most are roadside sites measuring the direct influence of road traffic. Concentrations measured at Beddington Lane are close to the annual mean objective, with an exceedence measured in 2009. The short-term NO2 objective is met at all of the sites except Wallington and Norbury.
6.68 NO2 concentrations have also been measured close to the site of the proposed ERF in three periods within the overall period of 18th May to 30th November -3 2011. During this period, the average NO2 concentration was 29.8 µg m , which is considerably lower than the annual mean concentration measured at the LAQN Beddington Lane monitoring station in 2011, of 37 µg m-3. This may reflect the low level of data capture of around 57% for NO2 over the three monitoring periods. In addition, the monitoring took place over the summer months when NO2 concentrations are typically lower than in the winter months.
6.69 A summary of period mean NO2 concentrations measured by diffusion tube at sites around the proposed development site from 23rd May to 12th September 2011 is presented in the air quality technical appendix. The period mean NO2 concentration is above the annual mean objective of 40 µg m-3 at four of the 19 Beddington diffusion tube locations. All four sites are adjacent to busy carriageways. The period mean measured by diffusion tube on Beddington Lane (M9) is in good agreement with that measured by the nearby Beddington Lane LAQN automatic monitoring station over the whole year, although the diffusion tube further south on Beddington Lane (M10) shows a much higher concentration.
6.70 Concentrations measured on Beddington Lane will not be representative of the baseline NO2 concentration at the majority of the sensitive receptors considered in the assessment. The average of concentrations measured at diffusion tubes located in residential areas (M2, M3, M4, M5, M12 and M13) may provide a more appropriate indication of the urban background concentration at receptor locations. The average concentration measured at these sites over the monitoring period was 30.8 µg m-3, which is 77% of the annual mean air quality objective.
6.71 The Defra mapped annual mean NO2 concentrations for the area surrounding the proposed ERF plant is around 21 µg m-3. This figure compares well with the concentration measured at the temporary automatic monitoring station, but is significantly lower than that measured by the LAQM monitoring station on Beddington Lane and many of the diffusion tube locations which are closer to road traffic and therefore not representative of the background.
Sulphur dioxide (SO2)
6.72 Continuous monitoring of sulphur dioxide (SO2) concentrations is not routinely undertaken by Sutton, Croydon or Merton. Monitoring carried out at urban background sites in Wandsworth and Lewisham indicates that short term concentrations are well within the SO2 objectives and there have been no reported exceedences in recent years.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
6.73 Automatic monitoring of SO2 was carried out close to the proposed site from 19th May to 4th July 2011. The mean concentration measured during this period was 5.4 µg m-3, with a maximum hourly mean of 28.6 µg m-3. The maximum measured hourly mean concentration is just 8.2% of the hourly mean air quality objective of 350 µg m-3.
6.74 Diffusion tube monitoring of SO2 has been carried out at six locations in the Beddington Lane area. The tubes were exposed for two week periods and therefore the data are not appropriate for comparison with the short term air quality objectives for the protection of health. A summary of the period mean of concentrations measured between 23rd May and 11th October 2011 is presented in table 6.10.
-3 Site Number of tubes Period mean SO2 concentration (µg m ) Bed M1 Triplicate 2.5 (a) Bed M6 Singular 2.5 Bed M8 Singular 1.7 Bed M11 Singular 2.0 Bed M12 Singular 2.9 Bed M13 Singular 5.2
Table 6.10: Period mean concentrations of SO2 measured by diffusion tube around Beddington Lane Average of triplicate tubes
6.75 The period mean concentrations are well within the long term (annual mean) -3 SO2 objective of 20 µg m set for the protection of sensitive habitats and ecosystems. The average SO2 concentration measured by diffusion tube is 2.8 µg m-3, just over half the concentration measured at the temporary automatic monitoring station.
6.76 The Defra mapped annual mean SO2 background concentration in the area is around 3.5 µg m-3. This figure compares well with the diffusion tube and automatic monitoring data and is assumed to provide a reasonable estimate of baseline SO2 concentrations at sensitive receptor locations.
Carbon monoxide (CO) 6.77 Continuous monitoring of carbon monoxide (CO) concentrations is not routinely undertaken by Sutton, Croydon or Merton. Automatic monitoring of CO was undertaken for Viridor close to the proposed site from 8th June to 30th November 2011. The mean concentration measured over this period was 300 µg m-3, with a maximum hourly mean of 6,400 µg m-3. The maximum hourly mean concentration was well within the short term (8 -hour mean) objective for CO of 10,000 µg m-3.
6.78 The Defra mapped background annual mean CO concentration in the area is around 200 to 210 µg m-3, which is in good agreement with the period mean measured close to the proposed site. Therefore, an annual mean concentration of 205 µg-3 is assumed to provide a reasonable estimate of CO concentrations at nearby sensitive receptors.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
Hydrogen fluoride (HF) 6.79 Monitoring of ambient concentrations of hydrogen fluoride (HF) by passive diffusion tube was carried out at six locations around Beddington Lane from 23rd May to 12th October 2011. A summary of the mean concentrations measured over this period is presented in table 6.11.
Site Number of tubes Period mean HF concentration (µg m-3) Bed M1 Triplicate 2.4 (a) Bed M6 Singular 3.1 Bed M8 Singular 4.3 Bed M11 Singular 3.5 Bed M12 Singular 3.2 Bed M13 Singular 2.5 Table 6.11: Period mean concentrations of HF measured by diffusion tube around Beddington Lane (a) Average of triplicate tubes
6.80 These measurement data suggest that the average baseline HF concentration at the development site and nearby sensitive receptor locations is likely to be around 3 µg m-3, which is not consistent with the anthropogenic background concentration quoted in the EPAQS Guidelines for Halogen and Hydrogen Halides in Ambient Air. This source suggests that only in heavily industrialised areas within Europe are background concentrations in the range 0.5 to 2 µg m-3, with measurements in the UK showing long term average concentrations below this level, even near industrial sources. The measurement data have been taken as being unreliable and instead a value for the background concentration has been adopted that is at the pessimistic extreme of national estimates.
Hydrogen Chloride (HCl) 6.81 Monitoring of ambient concentrations of hydrogen chloride (HCl) by passive diffusion tubes was carried out at six locations around Beddington Lane from 23rd May to 12th October 2011. A summary of the mean concentrations measured over this period is presented in table 6.12.
Site Number of tubes Period mean HCl concentration (µg m-3) Bed M1 Triplicate 8.8 (a) Bed M6 Singular 15.4 Bed M8 Singular 9.0 Bed M11 Singular 8.8 Bed M12 Singular 9.3 Bed M13 Singular 10.1 Table 6.12: Period mean concentrations of HCl measured by diffusion tube around Beddington Lane (a) Average of triplicate tubes
6.82 These measurement data suggest that the baseline HCl concentration at the site is likely to be around 10 µg m-3, which seems to be a highly implausible result, given our understanding of background HCl concentrations in the UK.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
The EPAQS report notes that the rural measurements made in the UK as part of Defra’s network indicate annual average concentrations in the range 0.12 – 0.41 µg m-3. On balance, these reported measurements are more likely to be representative of the Beddington area than the diffusion tube measurements. For this reason, a value of 1 µg m-3 has been adopted as the annual average background concentration for the assessment.
6.83 Ambient monitoring of HCl is carried out as part of the Defra Acid Gases and Aerosol Monitoring Network (AGANet) at 30 locations around the UK. However, all of the monitoring sites are rural and therefore unlikely to be entirely representative of background concentrations at the site. In 2009 annual mean concentrations of HCl in the network ranged from 0.088 to 0.49 µg m-3, considerably lower than the period mean concentration measured at Beddington Lane.
Volatile organic compounds (VOCs) 6.84 Continuous monitoring of benzene concentrations is not routinely undertaken in Sutton, Croydon or Merton, although automatic monitoring of this pollutant was undertaken by Mouchel close to the proposed site from 5th July to 30th November 2011. The mean benzene concentration measured over this period was 0.2 µg m-3, with a maximum hourly mean of 2.6 2 µg m-3. The average concentration is well within the long term air quality objective/ EU limit value of 5 µg m-3.
6.85 Monitoring of ambient VOC concentrations by passive diffusion tubes was carried out at six locations around Beddington Lane from 23 May to 11 October 2011. The average benzene concentration over this period was 0.72 µg m-3 (data capture < 90%). The concentration of 1,3-butadiene was consistently below the detection limit.
6.86 The Defra mapped 2010 background benzene concentration at the proposed ERF is around 0.65 µg m-3, which is just 4.0% of the annual mean objective concentration of 5 µg m-3. The estimated background concentration is in good agreement with that measured by diffusion tubes close to the proposed site. Therefore, in the absence of better quality site specific monitoring data, the mapped background is assumed to provide a reasonable estimate of baseline concentrations at the site.
Dioxins and furans 6.87 Monitoring of PCDD/Fs is currently carried out by Defra at six locations in the UK (Hazelrigg, High Muffles, London, Manchester, Auchencorth Moss and Middlesbrough). Hazelrigg and Auchencorth Moss are described as semi- rural and rural sites respectively and the remaining four sites are in urban locations.
6.88 To provide an indication of the range of PCDD/F concentrations that occur in the UK, a summary of the annual mean concentrations measured between 2006 and 2008 is presented in table 6.13 (more recent data have not yet been reported).
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
Year 2006 2007 2008 London 5.86 7.25 10.94 Manchester 18.69 18.33 18.99 Auchencorth Moss - - 6.44 Middlesbrough 16.95 18.49 23.98 High Muffles 0.47 1.35 1.73 Hazelrigg 26.83 6.68 3.67 Table 6.13: Summary of UK annual mean PCDD/F concentrations from 2006 to 2008 (fg m 3) (a) Where 1 fg m 3m3 (femtogram per cubic metre) is equivalent to 1 x 10-15 g m 3m3 or 1 x 10 9 µg m -3
6.89 The average concentration measured in central London from 2006 to 2008 was 8.0 fg m 3m3 and this is assumed to be reasonably representative of the baseline dioxin and furan concentration at the proposed ERF.
Trace metals 6.90 Monitoring of trace elements has been undertaken by the Defra since 1976. Currently monitoring of 12 metals is carried out at 24 predominantly urban locations. In addition, concentrations of arsenic, cadmium, mercury and nickel are monitored at a further 10 rural locations. To provide an indication of the range of trace metal concentrations that may occur in London, measured concentrations at Cromwell Road and Horseferry Road are summarised in table 6.14.
Cromwell Road Horseferry Road Assessment Criterion Metal (ng m3) (ng m3) (ng m3) Antimony (Sb) Not measured Not measured 5,000 Arsenic (As) 0.69 – 0.95 0.76 – 0.91 3 Cadmium (Cd) 0.16 – 0.20 0.17 – 0.20 5 0.2 Total chromium (Cr) 4.0 – 5.1 1.6 – 2.5 (a) 5000 (b) Cobalt (Co) Not measured Not measured 1,000 Copper (Cu) 40.5– 42.6 18.8 – 19.8 10,000 Lead (Pb) 11.1 – 12.8 10.4 – 11.4 250 – 500 Manganese (Mn) 9.2 – 9.6 5.8 – 6.7 150
Mercury (Hg) (c) 1.9 – 2.8 2.1 – 2.4 250 Nickel (Ni) 1.6 – 2.7 1.1 – 2.1 20 Thallium (Tl) Not measured Not measured 1,000 Vanadium (V) 2.7 – 2.9 2.5 – 3.2 5,000 Table 6.14: Range of annual mean trace metal concentrations (2007 to 2009) (a) Hexavalent chromium (CrVI) (b) Trivalent chromium (CrIII) (c) Total particulate and vapour
6.91 The average of the trace metal concentrations measured at both sites is assumed to provide a reasonable estimate of the baseline concentration in the vicinity of the proposed ERF and nearby sensitive receptors.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
Ammonia (NH3)
6.92 Ambient concentrations of ammonia (NH3) are measured at 95, largely rural, locations by the National Ammonia Monitoring Network. The closest monitoring site to Beddington Lane is at Cromwell Road in South Kensington. The average NH3 concentration measured over the last three years at this site was 3.3 µg m-3, which is just above the critical level for the protection of sensitive habitats and ecosystems of 3.0 µg m-3.
6.93 Automatic monitoring of NH3 concentrations was undertaken close to the proposed site from 30th September to 30th November 2011. The mean NH3 concentration over this period was 4.2 µg m-3, with a maximum hourly mean of 31 µg m-3.
Summary of background concentrations 6.94 A summary of the annual mean background concentrations used in the assessment is presented in table 6.15. In selecting values for the individual pollutants, professional judgment has been applied to the available data in order to propose numbers that are representative of the urban background, to which most of the receptors are likely to be exposed, and which are not overly precise, e.g. 3 µg m-3 and not 3.3 µg m-3. Given the high degree of spatial variability of concentrations for those pollutants associated with road traffic, notably NO2, it must be recognised that these estimates will not be uniform across the assessment area.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
Pollutant Annual mean Short-term -3 -3 Particles (PM10) 25 µg m 29 µg m (e) -3 Particles (PM2.5) 19 µg m n/a -3 Nitrogen Dioxide (NO2) 30 µg m 60 (d) (d)(e) -3 Sulphur Dioxide (SO2) 3.5 µg m 7 (d) 9 (d)(g) Carbon Monoxide (CO) 205 µg m -3 285 (d)(f) Hydrogen Fluoride (HF) 0.5 µg m -3 1 (d) Hydrogen Chloride (HCl) 1 µg m -3 2 (d)
Ammonia (NH3) 3 µg m 3 - -3 Benzene (C8) 0.65 µg m n/a 1,3,-Butadiene 0.28 µg m -3 n/a Dioxins and Furans 8.0 fg m -3 (b) n/a (PCDD/Fs) Cadmium (Cd) 0.2 ng m -3 (c) n/a Thallium (Tl) No data available - Mercury (Hg) 2 ng m -3 (c) 5ng m -3 (c)(d) Arsenic (As) 0.8 ng m -3 (c) n/a Chromium (Cr) 3 ng m -3 (c) 6. ng m -3 (c)(d) Cobalt (Co) No data available - Copper (Cu) 30ng m -3 (c) 61 ng m -3 (c)(d) Lead (Pb) 11 ng m -3 (c) n/a Manganese (Mn) 8ng m 3 (c) 16 ng m -3 (c)(d) Nickel (Ni) 2 ng m -3 (c) n/a Antimony (Sb) No data available - Vanadium (V) 3ng m -3 (c) 3 ng m -3 (c)(e) Table 6.15: Summary of background concentrations (a) Where background concentrations are expressed as range (e.g. Arsenic) the average concentration has been used (b) Units are fg m-3 (femtogram per cubic metre) equivalent to 1 x 10-15 grams per cubic metre (c) Units are ng m-3 (nanogram per cubic metre) equivalent to 1 x 10-9 grams per cubic metre (d) 1 hour mean background concentration estimated by multiplying the annual mean by a factor of 2 in accordance with the H1 Guidance (e) 24 hour mean background concentration estimated by multiplying the 1-hour mean by a factor of 0.59 in accordance with the H1 Guidance (f) 8 hour mean background concentration estimated by multiplying the 1-hour mean by a factor of 0.70 in accordance with the H1 Guidance (g) 15 minute mean background concentration estimated by multiplying the 1-hour mean by a factor of 1.34 in accordance with the H1 Guidance.
Odour 6.95 The existing waste management activities on the site, coupled with the local sewage treatment works, have been possible causes of odour complaints in the past.
Future baseline 6.96 It is anticipated that air quality in 2017 and beyond will be at least as good as it is now, if not better, as national and local policies relating to vehicle
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
emission performance will tend to reduce airborne concentrations of pollutants such as NO2 and PM10.
Pollutants in soils 6.97 Dioxin and furan concentrations at the five sites, expressed as I-TEQ (see the air quality technical appendix for an explanation of this measurement) are shown in table 6.16. Concentrations of dioxins/furans measured in soil around the proposed EWF location are in the range 2.1 to 6.4 ng I-TEQ kg-1. All of these are well within the expected range for urban background concentrations in England and are not substantially different from the median value for rural soils in England.
Site Soil concentration S1 Beddington Park 3.4 S2 Poulter Park 3.3 S3 Mitcham Common 6.4 S4 Pollards Hill 2.1 S5 Wandle Park 6.1 Typical England Rural Background Concentrations (a) Median: 2.53 Typical England Urban Background Concentrations (a) Median 11.11 Table 6.16: Dioxin/Furan concentrations in soil samples (ng I-TEQ kg-1) (a) UK Soil and Herbage Pollutant Survey, SHS Report 10 Environmental Concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in UK soil and herbage, June 2007 http://publications.environment-agency.gov.uk/pdf/SCHO0607BMTD-e-e.pdf?lang=_e
6.98 Table 6.17 shows the total concentrations for 12 PCBs measured at the five sites. They are expressed as ‘upper bound’, because, for some of the individual PCBs, the concentrations were below the limit of detection and the value for this in such cases has been used in compiling the aggregate value. When compared with the aggregate value the EA reported for a total of 27 PCBs, the measured values are very similar and do not indicate any notable historical pollution. There are 209 known PCBs in total, and the laboratory tested for the 12 that the World Health Organization recommends monitoring, because of their dioxin like behaviour.
Site Soil concentration, upper bound S1 Beddington Park < 0.78 S2 Poulter Park <0.80 S3 Mitcham Common <1.17 S4 Pollards Hill <0.50 S5 Wandle Park <1.09 Typical England Rural Background Concentrations (a) Median: 0.97 Typical England Urban Background Concentrations (a) Median 2.52 Table 6.17: PCB concentration in the soil samples (µg kg-1) as a grand total (a) UK Soil and Herbage Pollutant Survey, SHS Report 9 Environmental Concentrations of polycyclic aromatic hydrocarbons in UK soil and herbage, June 2007 http://publications.environment-agency.gov.uk/PDF/SCHO0607BMTC-E-E.pdf
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
6.99 Polycyclic aromatic hydrocarbons (PAHs) are generated mostly by combustion processes of varying kinds, predominantly where combustion is uncontrolled and is incomplete. There are several individual PAHs, of which the most important for air quality and human health is benzo(a)pyrene, which is a carcinogen.
6.100 The soil samples were investigated for 16 individual PAHs, designated by the US EPA as being the most important. Results for the total and for benzo(a)pyrene are shown below in tables 6.18 and 6.19. The results are more variable across the sites than for some pollutants, which reflect the multiplicity of sources for this family of pollutants and the role that very local sources are likely to play in spoil concentrations. None of the sites exhibit concentrations that are significantly outside expectations for urban soils in the UK.
Site Soil concentration S1 Beddington Park 3,700 S2 Poulter Park 23,000 S3 Mitcham Common 8,700 S4 Pollards Hill 4,400 S5 Wandle Park 23,000 Typical England Rural Background Concentrations (a) Median: 936 Typical England Urban Background Concentrations (a) Median 10,500 Table 6.18: PAH concentration in the soil samples (µg kg-1) as a grand total (a) UK Soil and Herbage Pollutant Survey, SHS Report 9 Environmental Concentrations of polycyclic aromatic hydrocarbons in UK soil and herbage, June 2007 http://publications.environment-agency.gov.uk/PDF/SCHO0607BMTC-E-E.pdf
Site Soil concentration S1 Beddington Park 350 S2 Poulter Park 2,400 S3 Mitcham Common 840 S4 Pollards Hill 300 S5 Wandle Park 2,300 Typical England Rural Background Concentrations (a) Median 67.2 Typical England Urban Background Concentrations (a) Median 714 Table 6.19: Benzo(a)pyrene concentration in the soil samples (µg kg-1) (a) UK Soil and Herbage Pollutant Survey, SHS Report 8 Environmental Concentrations of polychlorinated biphenyls in UK soil and herbage, June 2007 http://publications.environment-agency.gov.uk/PDF/SCHO0607BMTC-E-E.pdf
6.101 Trace metal concentrations measured at the five sites are shown in table 6.20. None of the individual metals exhibit concentrations that are exceptional by reference to the values reported for urban or rural soils by the Environment Agency and others. Of the five sites where sampling took place, Mitcham Common has the highest concentration for some of the metals investigated. This may be a reflection that parts of the common were once used as landfill sites for inert wastes.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
Median urban Beddington Poulter Mitcham Pollards Wandle background Metal Park Park Common Hill Park concentration S1 S2 S3 S4 S5 England (a) As 12.7 10 12 8 11 13 Cd 0.29 <1 <1 5 <1 <1 Cr III 24.5 17 17 40 25 17 Cr VI - <1 <1 <1 <1 <1 Cu 30.4 19 49 100 36 48 Hg 0.23 <1 <1 4 <1 2 Mn 386 260 150 110 150 190 Ni 22.0 10 14 17 18 13 Pb 115 86 160 350 96 220 Sb(b) 1.1-8.6 2 3 5 4 3 Tl(b) 0.12-0.29 <1 <1 <1 <1 <1 Zn 112 78 150 520 180 140 Table 6.20: Trace metal concentrations in soil samples (mg kg-1 dry weight soil) (a) UK Soil and Herbage Pollutant Survey, SHS Report 7 Environmental Concentrations of heavy metals in UK soil and herbage, June 2007 http://publications.environment- agency.gov.uk/PDF/SCHO0607BMTA-E-E.pdf (b) Background values taken from summary in Alloway BJ (1995) Heavy Metals in Soils published by Blackie Academic
6.102 Overall, none of the sites where soils were sampled for these pollutants indicate that concentrations are unusual or that prior atmospheric deposition has been exceptional, in comparison with what is known of typical soils in England.
Other significant planned or operating emission sources in the local area 6.103 There are a number of existing and possible future sources of emissions in and around the Beddington Lane area that need to be considered in the assessment, in the context of a possible cumulative impact with the proposed development.
6.104 On the existing application site, there are five landfill gas engines. These produce approximately 1 MWe each, although landfill gas production is such that only 4 MWe is generated at present. This is expected to decline to 1 MWe by 2017. The stacks are 7 m in height and dispersion is provided mostly by the buoyancy inherent in the hot gases. The combustion of methane produces NOx as the only significant pollutant of note, although there must be some potential for the emission of very fine particles. There will also be some unburnt hydrocarbons that escape destruction in the combustion process, mostly methane. Occasionally, the landfill gas has to bypass the engines and is flared.
6.105 The landfill gas engines are currently at the peak of their production and will decline in output with time. By 2017, the gas production in the landfill is forecast to be such that it can sustain only three engines and then decreasing to one by 2030.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
6.106 Viridor lodged a planning application in 2005 for an Anaerobic Digestion plant to treat 70,000 tonnes of waste. This development has been considered here as a theoretically possible additional point source of note. If this development were to proceed as planned, it would add two further gas engines of 0.5 MWe each close to the existing and proposed five landfill gas engines and be a source of NOx.
6.107 Other activities on the landfill site release pollutants and will have some localised impact on air quality, mainly of particulate matter associated with vehicle movements disturbing the ground and through bio-aerosol releases in the composting operations.
6.108 As the monitoring by the London Borough of Croydon has shown, other waste management activities by other companies along Beddington Lane also contribute to PM10 concentrations locally.
6.109 There is a planning approval for a gasification plant on part of the site currently occupied by Country Waste Management (87 Beddington Lane). The applicant is a joint venture known as Bioflame Limited. The proposal is for the generation of heat and power (2.63 MWe) from the gasification of waste wood (30,000 tonnes annually). This will require a 23 m high stack. If this proposal were to be implemented, the impact on local air quality would be very small in the context of the existing concentrations and will have its greatest impact close to the source. The main additional pollutant would be NOx and concentrations at specific receptors have been estimated for the ES that accompanied the planning application. This information can be used to make a cumulative assessment.
Sensitive receptors 6.110 In addition to predicting the maximum off-site impact, a number of discrete receptors have been considered which represent residential properties or public facilities that are nearest to the proposed ERF. The locations of the sensitive human health impact receptors considered for this assessment are provided in table 6.21 and presented in figure 6.5.
Receptor Description Grid reference London Road Residential 528263 166861 London Road/Goat Road Residential 528332 167153 Mitcham Common/ Golf Club Leisure 528747 167465 Beddington Lane Residential 529413 167145 North of Therapia Lane Residential 529683 166796 Wimshurst Close Residential 530257 166472 West of Beddington Lane Residential 530049 166041 Crispin Crescent Residential 529816 165522 Beddington Park Leisure 529021 165729 Primrose Close Residential 528590 166509 Table 6.21: Description of sensitive receptors 6.111 Guidance issued by Natural England and the Environment Agency suggests that any site of nature conservation importance designated at the European level within 10 km of a development of this kind should be considered as a
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
receptor and potential impacts assessed. This is a formal requirement of the Habitats Regulations (i.e. The Conservation of Habitats and Species (Amendment) Regulations 2011). Sites of Importance for Nature Conservation (SINCs) within 2 km should also be assessed.
6.112 In this assessment, the radius of interest for European sites has been extended to 15 km to fulfill a request by the Environment Agency. This criterion for inclusion leads to the following sites being considered as receptors in this context:
• Wimbledon Common Special Area of Conservation (SAC) • Richmond Park SAC • Mole Valley SAC
6.113 Within 2 km of the ERF, there are six Local Nature Reserves (LNRs), as follows:
• The Spinney • Spencer Road Wetlands • Bennett’s Hole • Wandle Valley Wetland • Wilderness Island • Crammer Green
6.114 The development site is situated within a Site of Importance for Nature Conservation (SINC) Beddington Farmlands. This site is designated primarily for the birds that use the wetland areas and is also a habitat for bats.
6.115 Further details and descriptions of these receptors can be found in the natural heritage chapter.
Impact assessment 6.116 The impact assessment has considered the following:
• Construction • Road vehicle emissions during construction and operations • ERF stack emissions • Plume visibility • Non-routine emissions • Odour • Ash handling
Construction 6.117 The principal issue for consideration is the generation and emissions of dust that could result in loss of amenity for nearby residents and businesses. There will be on-site generation of other emissions, through the use of machinery, but such emissions will be too small in magnitude to influence local air quality. In addition, the construction activity will require vehicle movements in and out of the site.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
6.118 The total period of construction for the ERF is anticipated to be 35 months, prior to the commencement of operations in 2017. The restoration of the landfill is on-going, but is anticipated to be complete by 2018.
6.119 The development site is, in the main, a substantial distance from receptors that might be affected by emissions of dust from construction activities. Residential areas are to be found to the north east of the development site (along Brookmead Road to the east of Beddington lane tram stop) and on the western boundary of the site (north of Hackbridge railway station around Foxglove Way).
6.120 The IAQM guidance notes that the most common impacts relating to construction activity are dust soiling and increased ambient PM10 concentrations. Dust soiling is caused by the deposition of particles of all sizes, but mostly particles greater than 10 µm in diameter. For both dust soiling and PM10 concentrations, the size of any impact is strongly related to proximity to the source of the dust, but also the effectiveness of the dust control measures in force on the site. The proposed development has four aspects that may give rise to dust emissions:
• Demolition of the existing structures (e.g. the composting facility) • Construction of the new facilities • Earthworks associated with the landscaping proposals • Trackout of dust on vehicles
6.121 These aspects are considered in turn, adopting the methodology in the IAQM guidance. However, it is important to note, that given that Beddington Lane is currently an AQMA with PM10 concentrations that are in part caused by the re-suspension of dust by heavy goods vehicles and there are also existing waste management activities that have a history of causing annoyance, it has been assumed that, as a minimum, standard dust mitigation measures will be put in place throughout the construction period and will be effective. Such measures include those shown in table 6.22.
Maintaining a high standard of housekeeping on site Using covered wagons and skips to ensure that dust arising from loaded wagons leaving the site is kept to a minimum Using controlled wet cutting methods for masonry and concrete products Damping down stockpiles and haul routes on site Restricting speed limits to minimise dust production Ensuring exhausts are not directly discharging to the ground Storing materials away from the site boundary and downwind of sensitive areas Implementing routine procedures for observing wind speed and direction prior to the commencement of any dust generating activities Where necessary, utilising environmentally friendly dust suppressants. Approval for use of such additives will be sought from the Environment Agency prior to use. Access roads may be treated in a similar way Utilising sprinkler systems if deemed necessary during periods of hot dry weather Conducting daily visual monitoring to ensure that there is no build up of dusty materials (spillages or unintentional deposits) and ensuring that if found, they are promptly cleared Controlling vehicle movements to ensure that only designated haul roads are used Minimising material handling operations
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
Fitting dust generating plant and machinery with suppression systems (grinders, saws, etc) Using vehicle cleaning and wheel washing facilities on site Banning bonfires Vegetating earthworks and exposed areas where possible Table 6.22: Standard dust mitigation measures to be employed during construction activities Demolition 6.122 While a number of the buildings to be demolished are large in volume, they are not substantial buildings, and are mostly a simple enclosure for the waste management activities. Their materials are not inherently dusty. Taking into account the size and type of buildings and the distance to the nearest receptor of significance, (more than 100 m away) demolition activities would be classified as low risk, possibly even negligible.
Construction 6.123 The volume of the new buildings is classified as large according to the IAQM guidance, being more than 100,000 m3 in volume. Piling will be required and there will be use of potentially dusty construction material, such as cement. The period of construction is a long one. The guidance adopts the categories of risk for construction dust that are set out in table 6.23.
Distance to nearest receptor Dust emission class
Dust soiling and PM10 Large Medium Small < 20 m High risk site High risk Medium risk 20 – 50 m High risk site Medium risk site Low risk site 50 – 100 m Medium risk site Medium risk site Low risk site 100 – 200 m Medium risk site Low risk site Negligible 200 – 350 m Low risk site Low risk site Negligible Table 6.23: Categories of risk for construction dust 6.124 Taking these factors into account, and the fact that the nearest receptors are more than 200 m away from the construction activity, construction is classified as low risk.
6.125 Also considered to be low risk, is the dust arising from the installation of the off-site grid connection.
Earthworks 6.126 Some preparation of the ground will be required, following the demolition of the existing buildings and the construction of the ERF and ancillary buildings. Of greater significance in the context of earthworks will be the restoration of the landfill site and the construction of the pipeline for the waste heat output along the western boundary of the site.
6.127 The guidance classifies as large a total site area of 10,000 m2, with a dusty soil type (i.e. clay) on which there are more than 10 heavy earth moving vehicles at any one time, with the formation of bunds more than 8 m high and a total of more than 10,000 tonnes of material being moved. This site qualifies for this description in terms of the overall size, when considering the landfill restoration, although the specific activity of the pipeline construction will
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
occupy a much smaller area. The risk categories defined are exactly as for construction above.
6.128 For most receptors, the risk is either negligible or low, but for some receptors on the western edge of the boundary, where the pipeline work takes place the risk might rise to medium, through proximity to the earth disturbance.
Trackout 6.129 When vehicles have been travelling on unpaved roads or open ground, they have the potential to accumulate mud and dirt on their wheels and other vehicle parts. This may then be transported off site onto the local roads, if vehicles are not washed and cleaned prior to departures. A similar potential exists at the present time on this site, as vehicles leave the landfill. The IAQM guidance notes that significant trackout may occur up to 500 m from large sites, 200 m from medium sites and 50 m from small sites. Risk categories form trackout are as shown in table 6.24.
Distance from road used by Dust emission class traffic to nearest receptor
Dust soiling and PM10 Large Medium Small < 20 m High risk site Medium risk site Medium risk Medium risk 20 – 50 m Medium risk site Low risk site site 50 – 100 m Low risk site Low risk site Negligible Table 6.24: Risk categories from vehicle trackout 6.130 Considering the length of the paved access road from the construction area to the public highway, i.e. Beddington Lane, and the absence of any significant numbers of residential or sensitive commercial properties near the entrance, this can be considered as a low risk site.
Conclusion and significance 6.131 The various construction activities present a low risk to the closest residential and commercial properties, principally because, in most cases, the distance from the source of any dust generation to these receptors is considerable. This separation and relative lack of human receptors makes the definition of the sensitivity of the surrounding area as medium, according to the IAQM guidance. Coupled with the low to medium risk of dust effects arising, this leads to the conclusion that the description of dust impacts is negligible and therefore not significant.
Road vehicle emissions during construction and operation
6.132 A summary of predicted annual mean NO2, PM10 and PM2.5 concentrations and 24-hour mean PM10 concentrations at the sensitive receptors selected for the assessment is presented in tables within the air quality technical appendix. The concentrations are those due to traffic emissions only and do not include the background concentrations.
6.133 The results indicate that the additional concentrations of all the pollutants considered are of imperceptible magnitude are not significant. This
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
conclusion applies for all receptors and it should be noted that these are roadside concentrations. Additional concentrations at points further from the road are even smaller.
ERF stack emissions 6.134 The concentrations at the maximum point of impact have been extracted and presented in table 6.25 for the pollutants with air quality objectives and which might exert an effect over the short term and long term.
Air quality ERF Background standard contribution Pollutant Concentration PC/AQS (AQS) (PC) (µg m-3) (µg m-3) (µg m-3)
Nitrogen dioxide (NO2) Annual mean 30 40 1.5 3.8% 99.79th%tile hourly means 60 200 7.5 3.7%
PM10 Annual mean 25 40 0.11 0.27% 90.41st %ile daily means 29.5 50 0.37 0.74%
PM2.5 Annual mean 19 25 0.11 0.43%
Sulphur dioxide (SO2) 99.18th %ile daily means 4.1 125 3.8 3.0% 99.18th %ile hourly means 7.0 350 5.2 1.5% 99.90th %ile 15 min means 9.4 266 5.7 2.1% Carbon monoxide (CO) 8 hour running mean 205 10,000 4.9 0.05% Hydrogen chloride (HCl) Max 1 hour mean 20 750 1.4 0.19% Hydrogen fluoride (HF) Annual mean 3 16 0.1 0.6% Max 1 hour mean 6 160 0.14 0.09%
Ammonia (NH3) Annual mean 3 180- 0.11 0.1% Max 1 hour mean 6 2500 1.4 0.1% VOCs (as benzene) Annual mean 0.65 5 0.11 2.2% PAH (as benzo-a-pyrene) Annual mean unknown 0.001 9.7 x 10-7 0.1% Imperceptible Impact magnitude descriptors Small Table 6.25: ERF contribution to airborne concentrations at the point of maximum impact 6.135 The impacts resulting from the additional concentrations of these pollutants, when assessed against criteria set for the protection of human health, are all either small or imperceptible, using the IAQM guidance to describe their magnitude. Taken in conjunction with the existing or background concentrations, the impacts are all either negligible or slightly adverse and are not significant in this context.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
6.136 The impacts of the additional NO2 concentrations can also be considered at the receptor locations representative of local residents and members of the public (presented in table 6.26). With regard to the AQMA, the area within it where NO2 concentrations are greater than 1% of the air quality standard is limited to the north west corner around Coomber Way and a portion of the western flank, adjacent to the BedZed development.
Receptor PC PC/AQS PC PC/AQS Annual 99.8th Description mean percentile (µg m-3) (µg m-3) London Road Residential 0.16 0.4% 4.3 2.2% London Road/Goat Road Residential 0.10 0.2% 4.2 2.1% Mitcham Common/ Golf Club Leisure 0.14 0.3% 4.8 2.4% Beddington Lane Residential 0.81 2.0% 6.3 3.2% North of Therapia Lane Residential 0.52 1.3% 6.6 3.3% Wimshurst Close Residential 0.31 0.8% 4.2 2.1% West of Beddington Lane Residential 0.30 0.8% 3.9 1.9% Crispin Crescent Residential 0.21 0.5% 3.1 1.5% Beddington Park Leisure 0.42 1.0% 4.4 2.2% Primrose Close Residential 0.54 1.4% 5.6 2.8%
Table 6.26 Additional NO2 Concentrations at Specific Receptor Locations 6.137 There is another group of pollutants that are persistent in the environment and for which effects might be apparent for long term exposure. These are the metals, along with dioxins and furans. The annual mean concentrations arising from the ERF of these pollutants are presented in table 6.27.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
Assessment ERF contribution Background criterion to annual mean Pollutant concentration PC/EAL (EAL) concentration (PC) (ng m-3) (ng m-3) (ng m-3) Dioxins and furans 0.000008 None 0.00000011 None Cadmium (Cd) 0.2 5 0.54 10.8% Thallium (Tl) unknown 1000 0.54 0.1% Mercury (Hg) 2 250 0.54 0.2% Antimony (Sb) unknown 5000 5.4 0.1% Arsenic (As) 0.8 6 5.4 90% Chromium (CrIII + 3 100 5.4 5.4% CrVI) Chromium (CrVI) 0.6 0.2 0.038 19% Cobalt (Co) unknown 200 5.4 2.7% Copper (Cu) 30 10,000 5.4 0.1% Manganese (Mn) 0.8 150 5.4 3.6% Nickel (Ni) 0.2 20 5.4 27% Lead (Pb) 11 250 5.4 2.2% Vanadium (V) 0.3 5000 5.4 0.1% Large Impact magnitude Medium descriptors Small Imperceptible Table 6.27: ERF contribution to annual mean concentrations of metals and dioxins at the point of maximum impact 6.138 The results show there is a considerable divergence in the magnitude of the impacts, which is largely dependent on the available assessment criteria. For thallium, mercury, antimony, cobalt, copper, manganese, lead and vanadium, the impacts are either small or imperceptible, and the impact can be described as negligible and not significant. For cadmium, arsenic, chromium and nickel, these results produce impacts that are large or medium.
6.139 A number of metals have been assigned stringent air quality guidelines. In particular, the Expert Panel on Air Quality Standards has made recommendations that go considerably beyond the environmental assessment levels that would be derived from applying factors to occupational exposure limits, as was previously done (i.e. using the EH40 document produced by the Health and Safety Executive.). The air quality technical appendix sets out the basis for the air quality standards and assessment criteria adopted for the assessment.
6.140 Emissions of certain of the metals considered require further investigation, i.e. cadmium, arsenic, chromium and nickel. The results presented above are essentially the outcome of a screening assessment, using worst case emission estimates that are based on an assumption of ERF performance against emission limits. In practice, the performance of energy from waste plants in relation to metal emissions is considerably better.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
6.141 This aspect has been investigated by the Environment Agency, by examining the routine emission monitoring data for metal concentrations at ten energy from waste plants operating in the UK. In addition, the chromium contents of flue gas treatment residues collected upstream of the emission point were investigated to derive concentrations of Chromium VI and Chromium III in the flue gases. These data are supplemented by other measurements reported in Defra Report WR 0608 on the Emissions from Waste Management Facilities (see the air quality technical appendix). Together, these two sources allow the estimation of more realistic release rates of metals from a modern energy from waste plant, through the application of factors to the release rates implied by the WID limit values. Table 6.28 sumarises the revised impacts when realistic emissions rates are used for those metals in table 6.27 showing medium or large impacts.
ERF contribution Fraction of Assessment to annual mean Pollutant WID limit criterion (EAL) PC/EAL concentration (PC) value (ng m-3) (ng m-3) Cadmium (Cd) 2.7% 5 0.0146 0.29% Arsenic (As) 0.14% 6 0.00755 0.13% Chromium (CrIII + 2.17% 100 0.117 0.12% CrVI) Chromium (CrVI) 2.17% 0.2 0.000819 0.41% Nickel (Ni) 4.4% 20 0.237 1.2% Large Impact magnitude Medium descriptors Small Imperceptible Table 6.28: ERF contribution to annual mean concentrations of certain metals, using realistic emission concentrations 6.142 Using these realistic estimates of the likely release rates for these metals, the conclusion is that impacts on local air quality will be negligible and not significant.
6.143 There are no air quality standards for dioxins and furans and so no conclusion can be drawn on the magnitude of the impact in relation to assessment criteria. It can be seen, however, that the additional contribution to airborne concentrations is very small, being at most about 1% of the estimated existing concentrations.
6.144 The metals and dioxins emitted by the ERF might have consequences for human health and this is considered both in the Health Impact Assessment (HIA) and the socio-economic and health effects chapter of the ES (the latter summarises the full report set out in the air quality technical appendix). An important aspect of this health risk assessment (as set out in the latter document) is the long term exposure to these pollutants, which are persistent in the environment and, in the case of dioxins, bioaccumulative. Thus, it is necessary to consider the exposure over many years and through multiple pathways, not simply inhalation of airborne concentrations. Another way of understanding the impact of the ERF’s emissions of these pollutants is to
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
compare the additional contribution to soil concentrations with those measured at the five sites sampled by RWDI.
6.145 As part of the health risk assessment, the deposition rate of metals and dioxins is calculated, using appropriate methodology and assumptions. If the point of maximum impact is taken, the contribution of this deposition to soil concentrations, over a defined period, can be calculated by assuming that the additional input is confined to a ‘box’ of area 1 m2 and a depth of 15 cm. (This is a depth often taken as representing the mixing that takes place in the upper soil through biological processes). The metals are very conservatively assumed not to be removed from this ‘box’ by biota or leaching. The outcome of this calculation is compared with the measurements reported in the baseline, as shown in table 6.29.
Existing Additional Deposition rate Percentage Pollutant concentration concentration (mg m-2 a-1) increase (mg kg-1) (mg kg-1) Arsenic 8-13 0.015 0.0023 0.03 Cadmium <1 - 5 0.03 0.0046 <0.5 Chromium III 17-40 0.24 0.037 0.2 Chromium V1 <1 0.0017 0.00026 <0.03 Mercury <1 - 4 0.034 0.0052 <0.5 Nickel 10-18 0.49 0.075 0.8 Lead 86-350 0.35 0.054 0.06 Antimony 2-5 0.073 0.011 0.6 Thallium <1 0.030 0.0046 <0.5 2.1- 6.4 2.22 0.0089 Dioxins and furans <0.4% (ng TEQ kg-1) (ng TEQ m-2 a-1) (ng kg-1) Table 6.29: Estimates of the increase in concentrations in metals and dioxins within local soils over 30 years 6.146 Even using the pessimistic assumptions regarding the metals remaining in the soil over 30 years, the incremental change in concentrations in the soil is very small. This is at the point of maximum impact, so all other places would experience an even smaller increase.
6.147 The results of the dispersion modelling in relation to those habitat receptors identified in the baseline, are presented in full in the air quality technical appendix. From a statutory perspective, the most important sites are the SACs at Richmond Park, Wimbledon Common and Mole Gap. These are all quite distant from the ERF (10 – 15 km) and so the additional concentrations and deposition rates of the relevant pollutants are too small to have any impact. All are at the 0.1% level when compared to the relevant assessment criteria, i.e. critical levels and critical loads1.
6.148 Some of the Local Nature Reserves (LNRs) identified in the baseline are closer to the ERF and, based on the dispersion modelling results, will
1 The critical level is the concentration of a gaseous pollutant at which harm might occur to the growth or development of a plant species or habitat. The critical load is the rate of deposition of acidity or nutrient nitrogen above which harm begins to occur through adverse effects on soil chemistry or through favouring the growth of some plant species above others.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
experience proportionately higher impacts. In particular, the following LNRs will experience additional concentrations of NOx and nutrient nitrogen deposition rates that are marginally greater than 1% of the relevant assessment criterion:
• The Spinney • Spencer Road Wetlands • Wandle Valley Wetland • Wilderness Island
6.149 These are small sites to the west of Beddington Park and the application site. Depending on the view taken of the appropriate critical load, the additional deposition rate for nitrogen varies between 0.8% and 2.5% at these sites. The Beddington Farmlands SINC will experience an increase in NOx concentrations, at its most affected part, of 0.72 µg m-3. This represents 2.4% of the critical level. This is not significant, primarily because this criterion relates to vegetation and it is unlikely that the vegetation at Beddington Farmlands will be affected and not in a manner that would affect the primary interest feature, which is the bird population
6.150 There are a number of nature conservation sites locally of lesser status than those listed above. Impacts at these sites have not been explicitly considered here, but have been addressed in the application for an Environmental Permit, at the request of the Environment Agency. Any implications for the nature conservation sites are discussed in the natural heritage chapter.
Conclusion and significance 6.151 The emissions to atmosphere through the two chimney stacks will result in some additional concentrations and deposition of a number of pollutants. Taken as a fraction of the relevant assessment criteria, the magnitude of these impacts can fairly be described as negligible for all pollutants, over the short term or long term, and even at the most affected location. In particular, this conclusion applies to those pollutants regulated by EU limit values and national air quality objectives. Consequently, they are not significant.
6.152 This analysis has been carried out assuming that the ERF emits each pollutant at a rate and concentration in the flue gases that is at the legal limit permitted by the WID. If the same assumption is applied to a number of metals, then the impact for these metals is medium or large. Such impacts would then be significant. In practice, however, this is a highly unlikely outcome. All the available data on emissions at existing energy from waste plant operating in the UK shows that the concentrations of these metals in flue gases are a very small fraction of the WID limit. If these actual emission data are used as an estimate of the likely release rates from the ERF, then the magnitude of the impacts is negligible or small, and the impact is not significant.
Plume visibility 6.153 The plume emitted from the two chimney stacks contains water vapour. When the ambient conditions of the atmosphere are sufficiently cold and humid, there is insufficient capacity in the atmosphere to allow this water to
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
remain in vapour form and it will condense into water droplets. This process produces a visible plume, which will appear white to an observer with the sun behind him / her, and dark should the sun be behind the plume (i.e. in front of the observer). The plume will cease to be visible at some point downwind of the stacks, when the plume has become sufficiently dispersed for the droplets to evaporate.
6.154 The ADMS dispersion model has been used to estimate the frequency and length of visible plumes, using inputs defining the moisture content of the plume and meteorological data containing hourly observations of relative humidity and temperature. The results of the plume visibility assessment are set out in table 6.30. This provides the percentage of the year when there would be a visible plume and includes the frequency for both day and night time.
Parameter Percentage of year visible plumes would have occurred 2007 2008 2009 2010 2011 No plume 87.2% 83.1% 83.6% 71.3% 84.7% 0-50m 9.0% 11.6% 10.9% 16.1% 10.3% 50-100m 3.2% 4.8% 4.5% 9.6% 4.5% 100-200m 0.6% 0.5% 1.0% 2.9% 0.4% 200-400m 0.0% 0.0% 0.0% 0.1% 0.0% >400 m 0.0% 0.0% 0.0% 0.0% 0.0% Average length (m) 41.0 39.8 43.4 51.9 41.6 Maximum length (m) 189 152 167 260 179 Table 6.30: Summary of plume visibility study results 6.155 The assessment shows that visible plumes are likely to be present for around 15% of the time in most years, but up to 29% in exceptional years (i.e. 2010). The plume length is predicted to be greater than 100 m for only approximately 1% of the year (3% for 2010) for day and night time. The plume will be white or grey depending on lighting conditions, and will be somewhat broken and diffuse as the plume disperses.
Peak and non-routine emissions
6.156 The dispersion modelling results have been obtained on the basis that the ERF is operating for all hours in the year with the pollutant concentrations exactly on the limit value prescribed by the WID. This is an extreme assumption, especially in the case of the annual average concentrations, since the facility could never operate with release rates as high as this in practice and remain compliant with legislation. In this scenario, the short term peak concentrations are determined by the worst case weather for dispersion (i.e. when the prevailing wind speed and atmospheric stability are such that parts of the plume come into contact with the ground relatively quickly). Such occasions are most likely to be on sunny, summer afternoons when convective downdraughts are present.
6.157 It might be argued that the short term peak concentrations will arise should the ERF be emitting some pollutants that are at concentrations within the half hourly WID limit values but greater than the daily limit values used for the
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
dispersion modelling. These pollutants are particulate matter, nitrogen dioxide, sulphur dioxide, hydrogen chloride and hydrogen fluoride. Such excursions above daily limit values are permitted for 3% of a year as set out in table 6.2. The probability of such occasions occurring at the same time as the meteorological conditions that produce the highest one hour mean ground level concentrations, as reported in table 6.25, is remote. However, in the unlikely event that this does occur, then the peak, one hour ground level concentrations would still be small and not significant.
6.158 When the ERF is shutting down or starting up, either because of a planned maintenance period or in response to an unplanned emergency event, the release rate (in mg s-1) of most pollutants should decrease, as the waste input to the furnace will cease and thereby reduce the generation of these pollutants, whilst at the same time the pollution control equipment will remain operational. An exception to this is dioxins, which will increase for a brief period, although not by an amount sufficient to change the value used in the modelling to reflect emissions over a year. The short term increase during a shut down and start up event is equivalent to the amount emitted by the ERF running normally for 4-5 days.
Odour 6.159 Municipal waste, especially in large quantities, is associated with odour. It does not follow, however, that the ERF will be a source of odour for local residents. The incoming waste will be unloaded into the tipping hall, which is within the building. The air within this part of the ERF is drawn into the furnace, which destroys all odorous compounds extremely effectively. At no point in the process of handling waste is there an opportunity for odours to escape to the atmosphere. Furthermore, the ERF will operate two lines, so that should one line be shut down, for maintenance for example, the other line will still be drawing air into the furnace. In addition, the flue gases emitted through the two chimney stacks are not odorous and the incineration process destroys all odorous compounds. Additional measures for dealing with odour, inherent in the design, maintenance and operation of the site, are set out in the proposals chapter. These design features and operating practices mean that there will be no impact from odour.
6.160 As part of the operating permit issued by the Environment Agency, Viridor will be required to devise an odour management plan to ensure that no odours are released and that this plan is adhered to over the working life of the plant.
Ash handling 6.161 Approximately 66,500 tonnes of bottom ash will be produced annually through the operation of the ERF. The ash will be stored temporarily in a bunker within the building, prior to its removal by road. The ash will be maintained in a damp state and is, at all times, within a building or a covered heavy goods vehicle at all times. Provided that operating floors and road surfaces are kept free of ash, there is no viable pathway by which this ash can become airborne and thereby contribute to local PM10 concentrations.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
6.162 A much smaller quantity of fly ash will be produced. The estimate is 9,800 tonnes annually. This material consists of the particulate matter removed from the flue gases by the fabric filtration system, which is collected in hoppers initially before transfer to a silo. This storage facility will have its own self cleaning filter system at the ventilation points and so the ash particles cannot escape to atmosphere.
6.163 The fly ash also contains the reagents used for the flue gas treatment, including the excess lime used in the removal of acid gases. It is the presence of this lime that causes the ash to be categorised as hazardous and it will be handled carefully during its removal from the facility. The ash will be transferred directly from the silos into bulk powder tankers and taken to a hazardous waste landfill site for disposal. At no point in this removal process does the ash have a viable pathway for escape to atmosphere and so there is no public exposure to the ash or the substances it contains and hence no impact.
Cumulative assessment 6.164 As noted previously, there are other point sources of pollutants in the vicinity of the development site. Of these, the most significant are the existing landfill gas engines operated by Viridor and possible additional gas engines which have planning permission, or for which permission is sought (i.e. Viridor’s anaerobic digestion plant.) The anaerobic digestion plant will also have a stack and be a significant point source.
6.165 To assess the impact of the ERF’s stack emissions in combination with these sources, the dispersion model has been run with the landfill gas engines as a source, and also with the gas engines and the ERF operating simultaneously. It is assumed in this extreme scenario that there are a total of seven gas engines and that they are operating continuously, with the ERF and the AD plant. A more realistic scenario has been considered for 2017 in which there are three landfill gas engines operating, alongside the ERF.
6.166 The pollutant of note in these scenarios is NO2. No other pollutants are emitted in significant quantities. Of particular interest here is the combined impact at the point where the ERF has the greatest impact. The modelling results have been summarised in table 6.31 as concentrations of NO2, for the location near Beddington Lane and Brookmead Road where the maximum occurs. Results are shown for each contributor in isolation and in combination.
Source Annual Average 99.79th Percentile ERF 1.5 7.0 Landfill gas engines 1.8 10.4 AD plant stack 1.1 5.4 Landfill gas engines + AD plant 2.9 15.9 All sources combined 4.3 15.9 ERF + 3 gas engines 2.6 7.9 -3 Table 6.31: Cumulative impact assessment results, as concentrations of NO2 (µg m ) 6.167 The available measurement data for existing concentrations at this part of Beddington Lane suggest that current NO2 concentrations (which include the
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
landfill gas engine contribution) are lower than the standard of 40 µg m-3, at about 37 µg m-3 close to the road and lower away from it.
6.168 In addition to the landfill gas engines, there is a proposed new source of NOx at 87 Beddington Lane, ie the Bioflame gasification proposal. This has been the subject of a planning application with an Environmental Statement, in which there are predictions for the additional NO2 concentrations at some receptors for which predictions also have been made in this assessment for the ERF contribution. A comparison is shown in table 6.32 for the annual average concentrations resulting from the two potential sources.
Receptor Description ERF Bioflame Combination
Beddington Lane Residential 0.81 0.65 1.46 Wimshurst Close Residential 0.31 0.84 1.15 West of Beddington Lane Residential 0.30 0.45 0.75 Table 6.32: Annual average concentration of NOx from the Bioflame gasification plant and the landfill gas engines 6.169 The impact of all three sources can reasonably be described as ‘small’ individually, although not insignificant. The measurement data indicate that whilst concentrations at the roadside are just below the air quality standard of 40 µg m-3, the existing concentrations at residential receptors are lower and that the additional concentrations from the ERF and Bioflame would not be the cause of non-compliance,
Mitigation 6.170 No additional mitigation is required to minimise further the impacts on air quality, beyond the control measures built into the project, although it should be noted that good practice during the construction phase is required to ensure that impacts are avoided.
Residual effects 6.171 Any construction activity has the potential to generate emissions of dust and thereby affect local amenity. In this case, most of the activities will take place at locations some considerable distance from any residential or commercial properties and the scale of any impact is likely to be small or negligible and is found to be not significant, using methodology proposed by the Institute of Air Quality Management.
6.172 Additional road traffic movements will arise during construction and operation of the ERF, with the increase in vehicle movements being dependent on the assumed baseline, which is variable according to the presence of an operational landfill. Beyond 2023, it is assumed that the landfill operations will have ceased in any event and so the ERF traffic will be wholly additional relative to a baseline of zero vehicles entering and leaving the Viridor site. In this scenario, and all other scenarios, the additional concentrations of NO2 and PM10 at the roadside along Beddington Road will be small in magnitude will not be significant, according to the Institute of Air Quality Management criteria.
Terence O’Rourke Ltd 227701 July 2012 South London ERF Viridor Chapter 6: Air quality
6.173 Emissions to atmosphere through the two ERF chimney stacks are the principal source of potential impacts associated with the ERF proposal. Such emissions will be required to comply with limit values set out in the WID and the environmental performance of the ERF will be subject to regulation by the Environment Agency through the operating permit required under the Environmental Permitting Regulations. The concentrations of certain pollutants in the flue gases will be measured at all times and the results made available to the public.
6.174 The additional ground level concentrations of a range of pollutants emitted by the ERF have been quantified as part of the assessment. The magnitude of the impacts has been found to be negligible, and the impact is judged to be not significant using criteria proposed by the Institute of Air Quality Management.
6.175 The impact of emissions to atmosphere on local sites of nature conservation interest has also been assessed and found to be not significant.
6.176 No residual air quality effects have therefore been identified.
Terence O’Rourke Ltd 227701 July 2012 Gair consulting
1. Croydon- Norbury !
1. Croydon- Norbury ! 2. Croydon - Thornton Heath !
2. Croydon - Thornton Heath !
8. Sutton - Beddington Lane ! 7. Sutton - Therapia Lane ! 8. Sutton - Beddington Lane ! 7. Sutton - Therapia Lane !
3. Croydon - George Street ! 3. Croydon - George Street !
6. Sutton - Carshalton ! 4. Croydon - Purley Way 6. Sutt!on - Carshalton ! 4. Croydon - Purley Way 5. Sutton - Wallington ! ! 5. Sutton - Wallington !
KEY: CLIENT: SIZE: TITLE: A4 Figure 4 ! LAQN Sites KEY: CLIENT: SIZE: TITLE: London Air Quality Networks A4 ! Monitoring Locations Figure 4 Site Boundary LAQN Sites London Air Quality Networks Monitoring Locations DASTEi:t e Boun23d Maary y2012 PROJECT: C55-P01
. Gair Consulting ReproducedLtd DRAW Nfrom: OrdnanceAJG Survey digital mapS Cdata.ALE : As Scale Bar DATE: 23 May 2012 PROJECT: C55-P01 0 1 © Crown Copyright. All rights reserved. 2102 Licence number 0100031673. SOURCE: Reproduced from Ordnance Survey digital map data. Crown DRAWING: . REV: Gair Consulting Ltd DRAWN: AJG SCALE: As Scale Bar copyright, All rights reserved. 2012 Licence number 0100031673 Figure4 LAQ0N.mxd 1 Kilometres British National Grid 0 PROJECTION: SOURCE: Reproduced from Ordnance Survey digital map data. Crown DRAWING: REV: copyright, All rights reserved. 2012 Licence number 0100031673 Figure4 LAQN.mxd Kilometres PROJECTION: British National Grid 0 South London Environmental Impact Assessment Fig 6.1 Energy Recovery Facility 0 1km London Air Quality Networks monitoring locations in the vicinity Gair consulting
M7 M2 (! (! M4 M8 (! (! M6 (! M5 M7 M2 (! (! (! M3 M4 M8 (! (! (! M6 (! M5 (! M9 M3 (! M11 (! (!
M9 M1 M13 (! M11 (! (! (! M14 (!
M10 M1 M13 M19 (! (! (! (! ! M14 ( M12 (! M10 M19 (! M15 (! M12 (! (!
M15 (!
M17 (!
M17 (! ! M18 M16 ( (! ! M18 M16 ( (!
KEY: CLIENT: SIZE: TITLE: (! Diffusion Tube Locations A4 Figure 5 KEY: Diffusion Tube Monitoring CLIENT: SIZE: TITLE: Site Boundary (! LDocifafutsioionns Tube Locations A4 Figure 5 Diffusion Tube Monitoring Site Boundary DATE: 23 May 2012 PROJECT: C55-P01 Locations
. Gair Consulting ReproducedLtd DRAW Nfrom: OrdnanceAJG Survey digital mapS Cdata.ALE : As Scale Bar 0 0.5 © Crown Copyright. All rights reserved. 2102 DATE: 23 May 2012 PROJECT: C55-P01 Licence number 0100031673. SOURCE: Reproduced from Ordnance Survey digital map data. Crown DRAWING: REV: copyright, All rights reserved. 2012 Licence number 0100031673 . Gair Consulting Ltd DRAWN: AJG SCALE: As Scale Bar Figure5 DT Locations.mxd Kilometres PROJECTION: British National Grid 0 0.5 0 SOURCE: Reproduced from Ordnance Survey digital map data. Crown DRAWING: REV: copyright, All rights reserved. 2012 Licence number 0100031673 Figure5 DT Locations.mxd Kilometres PROJECTION: British National Grid 0 South London Environmental Impact Assessment Fig 6.2 Energy Recovery Facility 0 500m Diffusion tube monitoring locations Gair consulting
(! S4
(! S3 (! S4
(! S3
(! S2
(! S2
(! S5 S1 (! S5 (! (! S1
KEY: CLIENT: SIZE: TITLE: (! A4 Soil Sampling Locations Figure 12 KEY: CLIENT: SIZE: TITLE: Site Boundary (! Soil Sampling Locations A4 Soil Sampling Locations Figure 12 Site Boundary Soil Sampling Locations DATE: 23 May 2012 PROJECT: C55-P01
. Gair Consulting ReproducedLtd DRAW Nfrom: OrdnanceAJG Survey digital mapS Cdata.ALE : As Scale Bar 0 0.5 © Crown Copyright. All rights reserved. 2102 DATE: 23 May 2012 PROJECT: C55-P01 Licence number 0100031673. SOURCE: Reproduced from Ordnance Survey digital map data. Crown DRAWING: REV: copyright, All rights reserved. 2012 Licence number 0100031673 . Gair Consulting Ltd DRAWN: AJG SCALE: As Scale Bar Figure12 Soil.mxd Kilometres PROJECTION: British National Grid 0 0.5 0 SOURCE: Reproduced from Ordnance Survey digital map data. Crown DRAWING: REV: copyright, All rights reserved. 2012 Licence number 0100031673 Figure12 Soil.mxd Kilometres PROJECTION: British National Grid 0 South London Environmental Impact Assessment Fig 6.3 Energy Recovery Facility 0 500m Soil sampling locations Gair consulting
KEY: CLIENT: SIZE: TITLE: AQMA Boundary A4 Figure 3 KEY: Air Quality Management Area CLIENT: SIZE: TITLE: Site Boundary BAoQunMdAa Bryoundary A4 Figure 3 Air Quality Management Area Site Boundary DATE: 23 May 2012 PROJECT: C55-P01 Boundary
. Gair Consulting ReproducedLtd DRAW Nfrom: OrdnanceAJG Survey digital mapS Cdata.ALE : As Scale Bar 0 0.5 © Crown Copyright. All rights reserved. 2102 DATE: 23 May 2012 PROJECT: C55-P01 Licence number 0100031673. SOURCE: Reproduced from Ordnance Survey digital map data. Crown DRAWING: REV: copyright, All rights reserved. 2012 Licence number 0100031673 . Gair Consulting Ltd DRAWN: AJG SCALE: As Scale Bar Figure3 AQMA.mxd Kilometres PROJECTION: British National Grid 0 0.5 0 SOURCE: Reproduced from Ordnance Survey digital map data. Crown DRAWING: REV: copyright, All rights reserved. 2012 Licence number 0100031673 Figure3 AQMA.mxd Kilometres PROJECTION: British National Grid 0 South London Environmental Impact Assessment Fig 6.4 Energy Recovery Facility 0 500m Beddington Lane Air Quality Management Area (AQMA) Gair consulting
3. Mitcham Com(!mon/ Golf Club
3. Mitcham Com(!mon/ Golf Club 2. London Road/Goat Road (! 4. Beddin(!gton Lane
2. London Road/Goat Road (! 4. Beddin(!gton Lane 1. Lond(!on Road 5. North of T(!herapia Lane 1. Lond(!on Road 5. North of T(!herapia Lane 10. Primrose Close ! 6. Wimshurst Close ( (!
10. Primrose Close ! 6. Wimshurst Close ( (!
7. West of Be(!ddington Lane
7. West of Be(!ddington Lane 9. Beddin(!gton Park
9. Beddington Park 8. Crispin Crescent (! (!
8. Crispin(! Crescent
KEY: CLIENT: SIZE: TITLE: (! Sensitive Receptors A4 KEY: Figure 13 CLIENT: SIZE: TITLE: Site Boundary (! SSeennssititiivve Recceepptotorsr Locations A4 Figure 13 Site Boundary DATE: 23 May 2012 PROJECT: C55-P01 Sensitive Receptor Locations
. Gair Consulting ReproducedLtd DRAW Nfrom: OrdnanceAJG Survey digital mapS Cdata.ALE : As Scale Bar 0 0.4 © Crown Copyright. All rights reserved. 2102 DATE: 23 May 2012 PROJECT: C55-P01 Licence number 0100031673. SOURCE: Reproduced from Ordnance Survey digital map data. Crown DRAWING: REV: copyright, All rights reserved. 2012 Licence number 0100031673 . Gair Consulting Ltd DRAWN: AJG SCALE: As Scale Bar Figure13 Sensitive Receptors.mxd Kilometres PROJECTION: British National Grid 0 0.4 0 SOURCE: Reproduced from Ordnance Survey digital map data. Crown DRAWING: REV: copyright, All rights reserved. 2012 Licence number 0100031673 Figure13 Sensitive Receptors.mxd Kilometres PROJECTION: British National Grid 0 South London Environmental Impact Assessment Fig 6.5 Energy Recovery Facility 0 400m Sensitive residential / leisure receptor locations