Impacts of energy system decarbonisation strategies on nitrogen oxides and fine particulate matter: A UK case study

International and national air pollution policies depend on air quality modelling to establish future emissions ceilings and targets for improving pollutant exposure. Historically, this modelling has typically relied on singular reference energy scenarios, with air pollutant abatement measures added. Greenhouse gas and air pollutant emissions are intrinsically linked through fuel combustion. Decarbonisation and net zero strategies will, therefore, yield significant co-benefits for air pollution. Consequently, the speed and pathway to net zero should be prominently considered within national emissions reduction targets and international renegotiations of air pollution protocols. We illustrate this by modelling the air pollution impacts of four UK 'Future Energy Scenarios' from the National Energy System Operator. Spatially apportioned impact factors are used from the UK Integrated Assessment Model (UKIAM) to provide rapid and replicable air pollution exposure assessments for UK energy system decarbonisation scenarios. We found that net zero scenarios relying on electrification exhibited 40 % lower nitrogen oxide emissions in 2050 than in a hydrogen-based scenario across energy production and use sectors. This led to 36 % and 15 % lower population exposure to nitrogen oxides and fine particulate matter, respectively, which could result in notable health benefits. The choice of energy system decarbonisation pathway has crucial implications for determining which additional air pollution abatement measures would be suitable. Therefore, a holistic approach should be adopted. Policymakers need to understand the net zero strategies being implemented to establish the relevant air pollution abatement options during this era of energy system transition.