Scenario modelling to support development of a long term air quality policy framework for Scotland

Description

1. As part of wider work to develop a long term policy framework to replace the Scottish Government’s existing air quality strategy Cleaner Air for Scotland 2 (CAFS2), which expires at the end of 2026, air quality objectives in Scotland are being reviewed. Although all current objectives are being met across the country, an increasing body of research shows that air pollution, even at the low levels currently experienced in much of Scotland, continues to harm human health across all life stages and in a multitude of different ways. 2. The Scottish Government’s aim is to propose challenging but achievable new objectives, thereby delivering further benefits for human health. In the short term, we wish to assess the feasibility of matching or where possible going further than the air quality targets for nitrogen dioxide and fine particulate matter, two pollutants of concern for human health, which are set out in the EU Directive 2024/2881 on ambient air quality and cleaner air for Europe and are to be achieved by 2030. In the medium to longer term (i.e. the 10-15 years after 2030), we wish to consider the feasibility of going beyond the EU targets and working towards the considerably more stringent World Health Organisation guidelines, which were updated in 2021. Any proposals will be subject to public consultation and approval by Ministers prior to being adopted. 3. The shorter term assessment does not form part of the requirements for this project, which instead focuses on the scope for further tightening of objectives beyond 2030. Lot 1: 6. The two main aims of the project are to: a) Develop a modelling procedure for assessing air pollutant emissions reduction scenarios: and b) Use this procedure for assessing the pollutant reductions that could be achieved for defined future years, and the associated human health benefits, from implementing specific policy packages. 7. To achieve this aim the project should: a) Either identify an established existing modelling methodology that will deliver the aims of the project or develop a bespoke methodology appropriate to the requirements. b) Undertake a testing phase to determine the utility of the chosen model and whether any modifications are required before full implementation. c) Use the finalised model to generate air pollutant emissions and concentrations scenarios for the pollutants nitrogen dioxide (NO2) and fine particulate matter (size fractions PM10 and PM2.5) for the year 2035 and for one or more additional years up to 2045. The initial analysis will be based on currently implemented policies together with additional policies set out in the Scottish Government’s updated Climate Change Plan that are relevant to air quality. Additional analyses based on hypothetical policy packages to illustrate what could be achieved with a greater level of ambition may also be required. d) Quantify as far as is feasible within the chosen methodology the human health benefits associated with these emissions and concentrations reduction scenarios. e) Produce outputs including but not restricted to reports, maps and data analysis tools that can be used to support robust proposals for tighter air objectives in Scotland.