We want people in Dundee to enjoy
• cleaner air
• better health
• a more pleasant and attractive city.
Air pollution is harmful to health, especially for
• the young
• the elderly
• those with heart and lung conditions.
Dundee has made progress in reducing levels of air pollution, however there are still streets where nitrogen dioxide (NO2) is at levels that exceed set objective levels so we need to take more action.
In Dundee (and most UK cities), road traffic is the main source of NO2.
Low Emission Zones can help reduce pollution from vehicle emissions, tackling both poor air quality and climate change. LEZs reduce pollution levels and improve air quality by stopping the most polluting vehicles entering a specific area.
Despite improvements in air quality since the introduction of the DCC Air Quality Action Plan in 2011, there remain locations in the city where the Air Quality Objective (AQO) for annual mean NO2 are not being met. While the number of exceedances of the NO2 annual mean objective has decreased, the proposed LEZ is to be introduced in the city to accelerate Dundee’s required compliance with the objective levels.
The full option appraisal process that has culminated in the identification of the preferred LEZ scheme option is described in detail within the ‘National Low Emission Framework - Interim Stage 2 report’ (8.6MB PDF). This document contains analysis of the National Modelling Framework (NMF) Air Quality Modelling work undertaken by the Scottish Environmental Protection Agency (SEPA), the Paramics Traffic modelling undertaken, the COVID-19 Uncertainty Study and the SEPA Emissions Analysis work referred to later in this statement. A shorter 'summary' version of the NLEF Interim Stage 2 report is also available for download ‘National Low Emission Framework – Stage 2 Assessment – Summary Note (2.2MB PDF).
The process has included identifying a range of high-level scenarios, some of which were then assessed in the Scottish Environmental Protection Agency (SEPA) Air Quality City Model for Dundee to see their effect on NO2 levels in areas of Dundee where there are current exceedances of the air quality objective level.
From this, five potential options were subjected to public consultation and stakeholder engagement in 2019 (2.2MB PDF). The five options included scenarios were the LEZ applied to buses only, to all vehicle types, and had three different possible areas based on the city centre bound by the inner-ring road. Over 1300 responses were received to the public consultation consultation, with 64% of respondents supporting the introduction of an LEZ applying to all vehicles. This option was also being favoured by bus operators. A report on this public consultation and stakeholder engagement was presented to Councillors in February 2020 (1.2MB PDF).
After this consultation, the five options plus additional Lochee Road inclusive variations requested during the consultation process, were assessed in a traffic microsimulation model to identify any potential impacts on the Dundee road network. The traffic modelling of the city centre only options helped to understand the localised impact of each option in restricting non-compliant vehicles from accessing the area inside the inner ring road and redistributing trips to car parks on the periphery of the proposed option area. When modelling the variations that included Lochee Road, the modelling suggested that the introduction of a LEZ incorporating the Lochee Road corridor significantly impacted on network conditions. The increase in network congestion was evident on all inner ring road option variants tested with both Lochee Road variants. 15 LEZ options in total were tested in the Dundee City Paramics traffic model and the model results clearly show there to be considerable impacts on the Dundee Road network if Lochee Road is included in any LEZ option.
In addition to the traffic modelling, further scenarios resulting from a COVID-19 Uncertainty Study that looked at plausible futures for travel post pandemic and how this may affect proposed LEZs in Scotland were also assessed in the traffic model. The results showed general network conditions between the Covid-19 sensitivity Reference Case and option models were relatively similar with no significant increase to network congestion or journey times on key routes. This modelling again however identified that the inclusion of Lochee Road options in the LEZ would result in localised rerouting of non-compliant vehicles.
For these reasons, all Lochee Road options were removed from the appraisal process and were not considered viable LEZ options. The final option which excludes the Bell Street, West Marketgait NCP, and Wellgate Centre carparks was chosen as the two other inner-city options which included these carparks would not have complied with Section 14(3)(a) of the Transport (Scotland) Act 2019 due to the carparks being considered being a ‘private road’ or directly accessed by a ‘private road’. Road safety considerations also mitigated against these options.
Based on the traffic modelling results and the 2019 public consultation, to help achieve compliance with NO2 air quality objective levels, and continued compliance with Particulate Matter (PM)10 and PM2.5 objectives, the LEZ is to apply to all vehicle types, apart from motorcycles and mopeds (which have been scoped out of the proposed LEZ scheme) and those subject to a national exemption outlined in the Low Emission Zones (Emission Standards, Exemptions and Enforcement) (Scotland) Regulations 2021.
Due to a significant cyber-attack, SEPA have not yet been able to undertake detailed air-quality modelling of the proposed Low Emission Zone (LEZ) option. However, an interim method has been agreed that focuses on road traffic emissions. This emissions analysis is outlined in the 'Dundee Emissions Analysis Report' (1.42MB PDF). The primary focus of the LEZ is to reduce local concentrations of Nitrogen Dioxide (NO2), which is the pollutant by which compliance against air-quality standards is assessed. This has therefore been the focus of previous air-quality modelling.
The emission analysis presented here focuses of emissions of Nitrogen Oxides (NOX), which describes the combination of NO2 emitted directly from vehicles as well as Nitrogen Oxide (NO) which can be converted to NO2 in the atmosphere. The next stage of detailed air-quality modelling will include predictions of NO2 concentrations. The interim emissions analysis of the proposed city-centre-only LEZ indicate an overall reduction in NOx emissions on roads within the LEZ of 78%. On Lochee Road that is outside of the LEZ boundary there is a reduction in NOx emissions of an average of 20%.
The decision to apply a 2-year grace period is driven by feedback obtained through previous consultation and stakeholder engagement as to how quickly those affected by the introduction of the LEZ in being able to become fully compliant. In addition, the unprecedented impact of the COVID-19 pandemic on society, including the wider environment and economy, needs to be considered. Potential implications for city centre businesses and bus operators suggests that a grace period greater than the required 1 year minimum is appropriate. The 2-year grace period would be applicable to all vehicle types from the same date to ensure consistency and ease of enforcement and wider communications. No additional grace period for residents of the zone is proposed.