Executive Summary

‘Transport 2010: The Ten Year Plan’ sets out the Government’s strategy to tackle congestion and pollution and deliver better integrated, high quality, transport systems over the next decade. A background paper ‘Transport 2010: The Background Analysis’ has also been published which provides an overview of the modelling and analytical work that has informed the Plan. The Background Paper includes forecasts of emissions of oxides of nitrogen and particles from road and rail transport in England in 2010 under a number of different scenarios. It also includes an assessment of the impact of the measures in the Plan on ambient NO2 and PM10 concentrations based on the methods described in the Air Quality Strategy for England, Scotland, Wales and Northern Ireland (AQS) and supporting technical reports. These methods have been updated to incorporate more recent ambient air monitoring results, understanding of atmospheric chemistry and emissions estimates and projections.

NO2 and PM10 are two important pollutants addressed in the AQS. They are pollutants for which the objectives set out within the Strategy and in recent EC Directives are likely to be the most challenging. This report describes these methods and presents the results of the site specific analyses of NO2 and PM10 concentrations. Concentrations of NO2 and PM10 in 2010 have been assessed for the road traffic emissions resulting from baseline and ‘plan’ scenarios and two illustrative scenarios of the impact of additional policy choices.

The background paper explains that the estimates of road traffic emissions and concentrations reductions should be treated with caution. DETR’s strategic road traffic modelling work has necessarily had to make broad assumptions about how the key decision-makers, particularly local authorities and the Mayor of London, will choose to spend the funds being made available by the Plan. It is unlikely to represent accurately the decisions that those bodies will make in the context of their local transport strategies and air quality management plans. In practice expenditure might be more targeted on localised problems.

The Plan is estimated to reduce annual average NO2 concentrations by, on average 3.1% (range 0.6–7.3%), compared to the baseline in 2010, with the biggest reductions predicted at roadside sites. The illustrative scenarios are estimated to produce reductions of, on average, 4.6 % (range 1.0-9.8%). On the basis of the assumptions underlying our air quality modelling, there would still be areas in London (centrally and near very busy roads) where the EC limit value and the Air Quality Strategy objective would not be attained, and possibly also near heavily trafficked roads in other large cities.

There are two sets of EC Directive limit values for PM10 concentrations: mandatory Stage 1 limit values for 2005, and more stringent non mandatory "indicative" Stage 2 limit values for 2010. Our analysis has focussed on the Plan’s contribution to achievement of the indicative annual mean Stage 2 limit value in 2010 - the timeframe of the Plan. Analyses presented in the Air Quality Strategy showed that this indicative limit value is likely to be widely exceeded across the country in 2010, with highest levels generally occurring next to heavily trafficked roads. The estimated reductions in concentrations arising from the Plan and illustrative scenarios are small: on average 1.8 % (range 0.6-5.4%) compared to the baseline for the Plan scenario; and on average 2.4 % (range 1.0-6.2%) under the illustrative scenarios. The reductions will nonetheless contribute to the Government’s broader strategy of reducing PM10 levels, which involves addressing non-transport sources in the UK and emissions from the rest of Europe.

Contents           Chapter 1

Report and site prepared by the National Environmental Technology Centre, part of AEA Technology, on behalf of the UK Department of the Environment, Transport and the Regions