COVID-19 green recovery should account for local variations in air quality

Published: 9 June 2020

By Adam Thirkill, Energy Innovation Research Office manager, Energy Systems Catapult

In the past few months, many cities around the world have benefitted from cleaner air as an unintended consequence of lockdown measures introduced to control the spread of COVID-19 [1, 2, 3, 4, 5].

Although this is balanced against the threat of infection, economic downturn and an impact to our general sense of freedom, it has nonetheless provided a glimpse of what could be achieved with respect to air quality with the right policies in place. Indeed, cities around the world are already thinking how to maintain clean air post-lockdown, with Copenhagen, Oakland, Los Angeles and Mexico City making great strides in this area.

Exposure to air pollution has been linked to an estimated 40,000 deaths per year in the UK. Particulate matter (PM), NOx and SOx contribute to a range of chronic health conditions affecting the respiratory and cardiovascular systems. Interestingly, a recent survey by the British Lung Foundation found one in six asthmatics in the UK noticed improvements in their symptoms during lockdown.

Moreover, recent studies into links between COVID-19 and air pollution suggest long term exposure to PM­2.5 and NOx is responsible for greater infection risk and death [6, 7, 8, 9]. The discovery of coronavirus attached to airborne PM has prompted further investigation into the role of air pollution as a potential carrier of the virus and whether this increases the infection risk.

Since long before the current COVID crisis, the UK Government has had two parallel objectives: to reduce greenhouse gas (GHG) emissions and improve air quality. The Clean Growth agenda recognised that the benefits of low carbon technologies go beyond GHG emissions, most prominently the impact on local air quality through reduced transport emissions. However, conflicts between low carbon and clean air strategies are possible if careful consideration to avoid decarbonisation at the expense of air quality is not taken.

Energy Systems Catapult has expanded the scope of its low carbon pathways model, ESME, to include six pollutants responsible for poor air quality. With this we are now able to model pollutant totals resulting from energy activities across the economy, and gain insight into the co-benefits and trade-offs between decarbonisation and air quality strategies. This provides a new angle to our whole-systems approach.

The Air quality modelling in ESME report presents analysis that shows to what extent decarbonisation can deliver improvements to air quality, and how the energy system changes when air pollution is actively minimised by the model using damage costs. This analysis was completed before the UK stepped up its commitment to hitting net zero GHG by 2050. In response to this, new preliminary analysis has been performed in a Net Zero context.

The analysis shows that in both 80% and Net Zero contexts, decarbonisation also delivers improvements in air quality, with stricter CO2 targets pushing further reductions in air pollution. This is not surprising given that many low carbon technologies also produce less pollution, but our analysis suggests these reductions are not enough to meet targets laid out in the National Emissions Ceilings Directive.

With this in mind, two key observations were made: first, the use of fuels and burners not compliant with RHI criteria risks near term PM2.5 targets not being met – of particular importance for biomass heating. Secondly, unless the switch away from fossil fuel use (especially in road transport) occurs sooner, 2030 NO targets will also be missed.

Our analysis also indicates that PM from brakes, tyres and road wear is an important source of emissions, shown to be greater than those from fuel combustion. Therefore, a shift to electric vehicles, whilst eliminating NOx and CO2 released by fuel combustion, may not deliver the expected improvements in air quality. This is an especially important consideration for cities which rely on the movement of people to prosper but also suffer from localised air pollution as a result. We suggest that a reduction in the total volume of cars on the road by making walking, cycling and public transport a sensible and obvious option to citizens, as well as investment in infrastructure to support measures such as working from home, would all mitigate air pollution from transport. A recent call for evidence on reducing non-combustion emissions from vehicles identifies similar measures.

Indeed it can be said that air quality is a highly localised issue and our analysis shows that whilst the national energy system is shaped overwhelmingly by the need to meet CO2 targets, the introduction of damage costs (monetary value ascribed to human health impacts, degradation of buildings/infrastructure, and loss of crop yields per tonne of pollutant emitted) drive regional differences in decarbonisation. For example, urban areas such as London see an earlier and greater shift to electric vehicles due to high damage costs associated with NO­x and PM emitted by fossil fuel combustion in densely populated environments.

Pursuit of a Net Zero economy is a powerful step to making the clean air after lockdown a permanent feature of living in the UK. However, consideration must be given to ensure policies intended to reduce CO2 emissions do not inadvertently reduce air quality. Models like ESME that can represent key emissions from across the UK economy can be used to assess the possible impacts of such policies. Regions and sectors where trade-offs might be permissible can also be identified.

Note: the original analysis contained in the report was commissioned by BEIS in an 80% emissions context. Energy Systems Catapult performed separate, preliminary Net Zero analysis which suggests the implications this new commitment has on air quality are broadly unchanged.