Smart Motorways Programme A1(M) Junction 6 to 8 Environmental Assessment Report Smart Motorways Programme Environmental Assessment Report Appendix 5.1 to 5.7 – Air Quality Tranche 5 – A1(M) J6 to 8 (Preliminary Design – PCF Stage 3) HE551539-WSP-EGN-SG-RP-LE-00016 May 2019 Notice This document and its contents have been prepared and are intended solely for Highways England’s information and use in relation to the Smart Motorways Programme. Environmental Assessment Report Smart Motorways Programme A1(M) Junction 6 to 8 Environmental Assessment Report Revision history Job number: 551539 Document ref: HE551539-WSP-EGN-SG-RP-LE-00016 Revision Purpose description Originated Checked Reviewed Approved Date P01 S3 – Draft for review Sioni Hole Bethan David Hoare Jonty Parry 01/03/19 and comment Tuckett Jones P02 S4 – Suitable for stage Sioni Hole Bethan David Hoare Jonty Parry 12/04/19 approval Tuckett Jones Client signoff Client Highways England Project SMP Tranche 5 – A1(M) Junctions 6 to 8 Document title Appendix 5.1 to 5.7 – Air Quality Job no. 551539 Document HE551539-WSP-EGN-SG-RP-LE-00016 reference Environmental Assessment Report Smart Motorways Programme A1(M) Junction 6 to 8 Environmental Assessment Report Table of Contents 5. Appendix 5.1 to 5.7 – Air Quality 1 5.1 Air Quality Assessment Strategy and Methodology Papers 1 5.2 Regulatory / Policy Framework 4 5.3 Baseline, Opportunities and Constraints 14 5.4 Traffic Data and Other Inputs 23 5.5 Model Verification 24 5.6 Assessment of Impact 31 5.7 Compliance Risk Assessment 48 List of Tables Table 5.1.1 - Ecological Receptors included in the Air Quality Model ............................................................... 2 3 Table 5.1.2 - Comparison of Annual Mean NO2 Concentrations (µg/m ) from Defra Background Mapping and Background Sites ............................................................................................................................................... 3 Table 5.2.1 - Relevant Air Quality Criteria 3 ...................................................................................................... 5 Table 4.3.2 - Summary of Roadside Annual Mean NO2 Trend Analysis ......................................................... 14 3 Table 5.3.3 - Annual Mean NO2 Diffusion Tube Monitoring Results (µg/m ) within A1(M) junctions 6 - 8 Geographical Study Area 5 ............................................................................................................................. 18 Table 5.3.4 - Highways England Diffusion Tube Monitoring Data (2013 - 2014) 6 ......................................... 20 Table 5.3.5 - Critical loads for Nutrient Nitrogen and Background Nitrogen Deposition7 ............................... 22 Table 5.5.1 - Diffusion Tube Sites Excluded From Model Verification 8 ......................................................... 24 Table 5.5.2 - Diffusion Tube Locations Used in Model Verification 9 .............................................................. 24 Table 5.5.3 - Comparison of verified Modelled and Measured NO2 Concentrations 10 ................................. 26 Table 5.5.4 - RMSE and Fractional Bias values for unadjusted modelled estimates of NO2 compared to monitored concentrations 11 ........................................................................................................................... 28 Table 5.5.5 - Comparison of Modelled and Measured NOx Concentrations 12 .............................................. 28 Table 5.5.6 - Model Adjustment Factors Applied in each Model Adjustment Area 13 .................................... 30 Table 5.5.7 - RMSE and Fractional Bias values for adjusted modelled estimates of NO2 compared to monitored concentrations 14 ........................................................................................................................... 30 Table 5.6.1 - Annual Mean NO2 Results for Discrete Human Health Receptors within Proposed Scheme’s Geographical Study Area 15 ........................................................................................................................... 31 3 Table 5.6.2 - Annual Mean NOx Results (µg/m ) for Ecological Receptors within the Proposed Scheme’s Geographical Study Area 16 ........................................................................................................................... 34 Table 5.6.3 - Nitrogen Deposition Results (kgN/ha/yr) for Ecological Receptors within the A1(M) J6-8 Geographical Study Area 17 ........................................................................................................................... 40 Table 5.6.4 - Regional Emissions Results – ‘Cumulative Worst Case’ Scenario 18 ....................................... 47 Table 5.7.1 - Compliance risk assessment results table – ‘cumulative worst case’ Scenario 19 ................... 48 Supporting Figures Figure 5.1.1 - Wind Rose Diagram for Luton Airport Metrological Station, 2017. ............................................. 2 Figure 5.3.1 - Sandy Roadside Mann-Kendall and Sen Estimate of Annual Mean NO2 Trend 2 ................... 15 Figure 5.3.2 - Cambridge Roadside Mann-Kendall and Sen Estimate of Annual Mean NO2 Trend ............... 16 Figure 5.3.3 - Annual Mean NO2 Future Year Concentration Projections 4 .................................................... 17 Environmental Assessment Report Smart Motorways Programme A1(M) Junction 6 to 8 Environmental Assessment Report 5. Appendix 5.1 to 5.7 – Air Quality 5.1 Air Quality Assessment Strategy and Methodology Papers The full methodology for the Air Quality assessment was agreed with Highways England the Air Quality Assessment Strategy and Methodology Papers (Document references: HE551539-WSP-GEN-SG-RP-ZM-0012 and HE551539-WSP-GEN-SG-RP-ZM-0013). Model Setup - Emission Rates The emission rates used in the local air quality modelling were derived from Interim Advice Note (IAN) 185/15 on speed banding. In accordance with IAN 185/15 the traffic modellers undertook speed pivoting where required including: • Analysis of the performance of modelled traffic speeds on individual road links compared against observed speeds on the same road links; • Adjustment, where required, of modelled traffic speeds on individual road links to better reflect observed speeds; this is known as the “Speed Pivoting” approach; • Assignment of individual road links into a speed-banding category by road type; and • Adjustment, where required, of assigned speed band where changes in speed did not justify a change in speed band (speed change less than 5 kph) or where a speed band change was considered by the traffic modellers to not reflect a valid Proposed Scheme impact. The emission rates for each hour were calculated as follows: • Step 1 – Weekday morning peak (AM), inter peak(IP), evening peak (PM), off peak (OP) hourly flows (in terms of light duty vehicles (LDV) and heavy duty vehicles (HDV)) for each road link were obtained from the traffic model and a speed band assigned to each road link for each period. • Step 2 – The traffic modellers were consulted to confirm which hours the relevant traffic model periods apply to. These were confirmed as: – AM: 07:00 – 10:00 (3 hours); – IP: 10:00 – 16:00 (6 hours); – PM: 16:00 – 19:00 (3 hours); and – OP: 19:00 – 07:00 (12 hours). • Step 3 – Emission rates for each time period were calculated using the using the flow, %HDV speed and road type using the “IAN 185-13 Speed Band Emission Factors v2” spreadsheet tool. • Step 4 – Emissions for each time period were input into the ADMS-Roads model and a “fac” file used to specify which hourly emission rate is used over each hour of the day. Model Setup – Dispersion Hourly sequential meteorological data for 2017 for Luton Airport Meteorological Station were used. The parameters required by the model included: date, time, wind direction (angle wind blowing from), wind speed (at 10m above ground level), surface air temperature (degrees Celsius), and cloud cover (oktas – or eighths of sky covered). The wind rose from Luton Airport metrological station (presented below in Figure 5.1.1) indicates that the dominant wind direction for 2016 was from the south-west. Environmental Assessment Report 1 Smart Motorways Programme A1(M) Junction 6 to 8 Environmental Assessment Report Figure 5.1.1 - Wind Rose Diagram for Luton Airport Metrological Station, 2017. The meteorological station is situated 15km to the west of the Proposed Scheme, with no significant topographic variation to the modelled region, and is therefore considered to be a good representation. Model Setup – Receptors Table 5.1.1 presents the ecological receptor locations within the Proposed Scheme’s geographical study area included in the air quality model. The locations of human health and ecological receptors are shown in Figure 5.2 Chapter 5: Air Quality. Table 5.1.1 - Ecological Receptors included in the Air Quality Model ID Distance to Name X Y Local road (m) Authority KW101-121 0 Knebworth Wood SSSI 523157 223173 Stevenage KW201-121 0 523228 223085 Stevenage KW301-121 0 523297 222984 Stevenage KW401-121 0 523343 222893 Stevenage SW101-121 0 Sherrardspark Wood 522463 214222 St Albans SW201-121 0 SSSI 522435 214149 St Albans SW301-121 0 522371 213995 St Albans SW401-121 0 522340 213893 St Albans Background Concentrations Estimated annual mean background NO2 concentrations for 2017 (the air quality assessment base year) were obtained from the background mapping provided on the Defra UK-AIR website. In 2017, there were no background continuous monitoring