In Climate Action, Don’t Neglect Air Pollution

President Trump recently attempted to appeal to environmentally minded Americans by invoking the cleanliness of America’s air, tweeting "America: the cleanest air in the world - BY FAR!" Trump is partly right, but mostly wrong about America’s low air pollution. The US has indeed reduced levels of the main air pollutants by 68% on average since 1980, mostly since regulations like the Clean Air Act and CAFE standards began targeting air pollution in earnest. But, he is very wrong to think the challenge of US and global air pollution is solved. Annual deaths from US air pollution (about 90,000) today are still higher than deaths from car accidents (44,000) and homicides (20,000). The air pollution problem is still so large, it actually offers a better rationale for transitioning to cleaner energy than even climate change.

Burning fuels for energy — in our cars, power plants, factories, and airplanes — is the source of most air pollutants and CO2 emissions. Despite this common source, CO2 and air pollution have historically been addressed in very different ways — with air pollution targeted through regulatory approaches and CO2 through a mix of federal tax credits and state-level renewables mandates. And yet policies that address one will often create co-benefits from the other. How do these benefits compare, and how should future energy policies be evaluated? Given the global scale of climate change, is air pollution worth heavily considering? To answer these questions, we did a systematic review of cost-benefit studies on the subject.

We compared the monetized benefits of energy policies for the climate and air pollution, and found that air pollution consistently offers more potential benefits relative to costs. Using papers with standardized methods for assessing the long-term economic impact of various health damages and climate benefits, we compared how energy policy impacts both GHG and criteria pollutant emissions, and the associated economic benefit. As our review of 9 US policy analyses shows, the reduced pollution was consistently more valuable than the avoided greenhouse gas emissions across various model parameters and locations considered.

Not only do the estimated public health benefits from clean energy deployment policy tend to match or exceed the climate-related benefits in many regions, we found they consistently exceed the cost of the policy itself. As the above figure shows, energy policy for the climate’s sake is a good economic bet, but energy policy to clean the air is even better.

A 2017 paper by Wiser et al. studied the air quality and climate benefits of a Rust Belt Renewable Portfolio Standard (RPS). Renewables mandates (or, even better, clean energy standards) are popular state policies to reduce climate impacts by mandating a certain amount of renewable (or clean) energy. In the coal-heavy Rust Belt, the RPS in the study led to a broad displacement of coal power plants. These plants dump so much pollution in the air that the health benefits are substantial. Despite the ostensible climate focus of this policy, the air quality benefits are greater than the intended climate benefits.

This is not unique. Several other papers showed that reducing air pollution and climate change mitigation go hand in hand. Because the sources of pollution and greenhouse gases tend to be the same, many of the solutions to air quality improvement will also yield climate benefits.

Using the significant damages from air pollution as a rationale for combined CO2 and pollution-reduction policies has already led to international action. This strategy has already been successfully implemented by China and is being developed in India, nations with the some of the highest pollution levels. Both China and India saw the opportunity to reduce their pollution and CO2 emissions by focusing on electric vehicles and non-coal electricity in pollution prone areas.

To compound this point, there is more political will to act on public health than climate change. Communities with air quality issues tend to care about and want action on those issues, even if they are not engaged on other environmental issues. This allowed for bipartisan action, such as the G.H.W. Bush Administration strengthening the Clean Air Act or taking action to limit black carbon emissions. While climate change is a global problem, non-CO2 pollution issues are localized by country, region, geography, and wind patterns — meaning air pollution will tend to damage the region it is produced in most. Even in places where climate action lags, air pollution could create a political opening.

Brian Sergi, a researcher at NREL and 2012 Breakthrough Generation Fellow, provided a vision of what co-optimized pollution and climate-focused energy policy could look like. By optimizing for both, energy planners can better prioritize specific power plant retirements and unlock even greater health benefits than with climate policy alone. Rather than creating health benefits as a “co-benefit” of climate action, this kind of co-optimized energy policy can unite the two goals intentionally.

As Trump said, we do have some of the cleanest air in the world. Mostly thanks to decades of clean air regulations that his administration is now trying to gut. Amid attempts to undercut these regulations, we must not lose sight of the remaining ground to gain on air pollution. Energy policy is a tool to act on both greenhouse gas emissions and air pollution. Wielding it to act on both is more than getting more bang for our buck, but also advances sound environmental protection in the present and the future.