The Air Quality Co-benefits of a Low Carbon Economy in Europe

Air quality in Europe has improved since the Industrial Revolution, however, Europe still experiences greater than average mortality due to air pollutant exposure. Many of the sources of air pollutants are the same as those of greenhouse gases and thus, in theory, societal developments designed to mitigate climate change could also improve air quality.

This is however, more complex than it seems on the face of it, as the dominant sources of air pollutants can modify the efficacy of climate mitigation for achieving air quality co-benefits. Secondary pollution can also pose an issue, particularly regarding ozone, which is projected to increase as the climate changes. Nevertheless, if air quality co-benefits of climate change mitigation can be achieved in Europe, this could be very impactful for public health, counteract any mitigation costs and help position European policymakers as climate leaders, potentially encouraging more ambitious mitigation in countries that emit more greenhouse gases.

There are many studies that consider co-benefits, however, this is challenging to model. Modelling air quality tends to require very detailed and computationally expensive models that run at a fine enough resolution to capture elevated urban concentrations and have a detailed representation of chemistry. Modelling climate change however, is best undertaken using global climate models, which trade resolution and chemistry for the ability to capture physical changes in the climate system over very long periods. Up to now, most of the research uses the latter. Additionally, recently, new scenarios for driving these models were developed. These Shared Socioeconomic Pathways provide a greater representation of the societal changes, many of which would be extremely meaningful for air quality, than the prior Representative Concentration Pathways upon which much of the existing research is based.

This thesis uses the more recent SSPs and a regional atmospheric chemistry model to model air quality co-benefits of a low-carbon economy in Europe compared to a “business as usual” pathway and a “low mitigation pathway”. This better represents the impacts at a scale relevant to European policymakers, and allows for more detailed analysis of the drivers of future air quality local to Europe. It does however, have a limitation in that the physical effects of climate change on air quality are not considered.