Draft UK Air Quality Plan for tackling nitrogen dioxide Technical Report May 2017 © Crown copyright 2017 You may re-use this information (excluding logos) free of charge in any format or medium, under the terms of the Open Government Licence v.3. To view this licence visit www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ or email [email protected] This publication is available at www.gov.uk/government/publications Any enquiries regarding this publication should be sent to us at Joint Air Quality Unit Area 2C Nobel House 17 Smith Square London SW1P 3JR Email: [email protected] www.gov.uk/defra Corrigendum Amendment Justification Page 77, Table 4.13 Public cost incorrectly transposed from modelling to this document. The previous Public impact figure changed from figure did not include the traffic flow £2,700m to £1,900m. benefit of £718m set out on page 73. The amendment reduces the net cost from £2,700m to £1,900m. Page 187, Table 10.1 Public cost incorrectly transposed from modelling to this document. The previous Public impact figure changed from figure did not include the traffic flow £2,700m to £1,900m. benefit of £718m set out on page 73. The amendment reduces the net cost from £2,700m to £1,900m. The amendments are highlighted in the main text. Contents Executive Summary ................................................................................................... 1 1. Introduction .......................................................................................................... 14 1.1 The air quality challenge ................................................................................. 14 1.2 Regulatory framework ..................................................................................... 17 1.3 Goal ................................................................................................................ 19 1.4 Uncertainty ..................................................................................................... 21 1.5 Actions to improve air quality .......................................................................... 22 2 Air quality assessment .......................................................................................... 23 2.1 Methods .......................................................................................................... 23 2.2 Results ............................................................................................................ 29 2.3 Discussion ...................................................................................................... 33 3. Option assessment ............................................................................................... 34 3.1 Introduction ..................................................................................................... 34 3.2 Identification of options for emission reduction ............................................... 36 3.3 Impact assessment methods .......................................................................... 43 3.4 Theoretical maximum technical potential of options ....................................... 55 3.5 Conclusion ...................................................................................................... 57 4. Clean Air Zones.................................................................................................... 58 4.1 Introduction ..................................................................................................... 58 4.2 Local measures .............................................................................................. 59 4.3 Charging zones ............................................................................................... 61 5. Measures to support Clean Air Zones .................................................................. 78 5.1 Introduction ..................................................................................................... 78 5.2 Retrofit ............................................................................................................ 78 5.3 Scrappage ...................................................................................................... 84 5.4 Ultra Low Emission Vehicles .......................................................................... 92 6. National measures ............................................................................................... 99 6.1 Introduction ..................................................................................................... 99 6.2 Speed limits .................................................................................................... 99 6.3 Government vehicles .................................................................................... 110 6.4 Measures to encourage behaviour change ................................................... 116 7 Distribution of effects across population groups .................................................. 128 7.1 Introduction ................................................................................................... 128 7.2 Health effect.................................................................................................. 128 7.3 Financial effect .............................................................................................. 132 7.4 Conclusion .................................................................................................... 145 8. Sensitivities and uncertainties ............................................................................ 146 8.1 Introduction ................................................................................................... 146 8.2 Uncertainties in the modelling of air quality .................................................. 147 8.3 Measure modelling uncertainties .................................................................. 156 8.4 Uncertainties in quantifying and valuing air quality impacts .......................... 165 8.5 Discussion .................................................................................................... 169 9. Future steps ....................................................................................................... 170 9.1 Developing the final Plan .............................................................................. 170 9.2 Evaluation of the final Plan ........................................................................... 177 9.3 Improving air quality evidence in the longer term.......................................... 179 9.4 Broader air quality strategy ........................................................................... 182 10. Conclusion ....................................................................................................... 184 10.1 Summary of results ..................................................................................... 184 10.2 Discussion .................................................................................................. 189 Annexes ................................................................................................................. 192 Annex A – Air quality model quality assurance ................................................... 192 Annex B – Fleet Adjustment Model..................................................................... 195 Annex C – Theoretical maximum technical potential .......................................... 215 Annex D – Clean Air Zones ................................................................................ 226 Annex E – Guidance on calibrated uncertainty language from the Intergovernmental Panel on Climate Change ..................................................... 229 Annex F – Report on the outcomes of the Air Quality Review meeting .............. 231 Annex G – Reporting zone NO2 concentrations.................................................. 236 Annex H – Assessment of methodologies for interpolating trends in NO2 concentrations for non-modelled interim years ................................................... 238 Annex I – Glossary of terms ............................................................................... 243 Executive Summary The air quality challenge The quality of our air is important for public wellbeing. Over recent decades, air quality has improved significantly. However, there is increasing evidence to suggest that air quality can adversely affect health, the natural environment, and economic performance. For example the Department of Health has identified air pollution as one of the biggest health risks across the UK. The most immediate action required on air quality is tackling the problem of nitrogen dioxide (NO2) concentrations around roads - the only statutory air quality limit value that the UK is currently failing to meet. There are a range of challenges associated with tackling NO2, including: Firstly, the uncertainty that is inherent to assessments of this kind. Some of this relates to the need to model changes into the future, such as uncertainty about how future vehicle standards will perform. Previous standards to control emissions from cars have not performed as expected, which has led to revised emission projections revealing more areas with high NO2 than previously modelled. Secondly, any plan to improve air quality is part of a wider landscape. Air pollution is an unintended consequence of many everyday activities, including driving and manufacturing. These