The burning of fossil fuels that harms our climate also produces air pollution that damages ecosystems and harms our health. But we fail to tally up the benefits of reduced air pollution in our climate policies, and overlook opportunities to tackle these problems together.
A reminder of this failure is illustrated in a new study which has found that reduced air pollution from net zero policies in the US could result in a health gain of between $65bn (£51bn) and $128bn in 2035 alone.
Dr Alex Barron, of Smith College, Massachusetts, who was part of the research team, said: “A decarbonised society means cleaner air. At the same time, how many clean air benefits we realise and who benefits will depend on how policymakers shape this transition.”
In Europe, the mistaken notion that diesel and wood are relatively climate-friendly fuels has left people living with excessive traffic emissions and in air pollution hotspots from home wood burning.
Six separate teams worked separately to model the economics of carbon dioxide and air pollution reduction for future US energy pathways.
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Dr Dan Loughlin, a scientist at the US Environmental Protection Agency and the first author of the study, said: “The modelling results were consistent: decarbonisation reduces co-emitted air pollutants and is expected to result in significant health benefits over the long term. Electrification combined with wind and solar tend to drive greater air pollutant emission co-reductions than many other decarbonisation pathways.”
The gains would be reduced if current coal use is replaced by fossil gas or biomass. Obviously, biomass fuels produce air pollution when they are burned. But two of the models increased air pollution from clearing unmanaged lands for bioenergy crops and increased fertiliser use.
Loughlin explained: “Our analysis provides a peek into this response, suggesting that greater ammonia emissions occur in scenarios with greater use of biomass.”
There was uncertainty about technologies to capture and store carbon. These have not been deployed at scale before and could offset some air pollution reductions if they are powered by combustion.
However, it was clear that policies for US net zero by 2050 could result in rapid health gains. By 2035, early deaths from air pollution could be reduced by between 4,000 and 15,000 a year, with even greater benefits thereafter. The largest gains would be in the central and north-west US states.
The $65bn to $128bn financial gains from fewer people dying early from air pollution exposure are at least as big as the financial benefits from avoiding direct damage from a changed climate.
Barron said: “It is really important to note that we are learning new things every day about the ways in which air pollution impacts our mind and our bodies. It won’t surprise me if the benefits are greater in retrospect than they appear in advance. People really value cleaner air as a near-term benefit of climate action, but the models we use to analyse climate policies don’t always make that part of the story clear to decision makers and the public.”