Air quality regulations worked in Atlanta! (but I’m glad we checked)

Luke Henneman
4 min readApr 19, 2018


Photo by Joe Yates on Unsplash

It’s no secret that current US government officials are wary of regulations.

Environmental rules have been in the crosshairs of President Trump’s team for the past year. Environmental Protection Agency (EPA) Administrator Scott Pruitt and others have led a major rollback of regulations that aim to limit emissions into our country’s air and water. Just last week, President Trump signed a presidential memo that set the stage for the EPA to weaken protections under the Clean Air Act.

This focus on repealing regulations raises questions: Have environmental rules been effective? Can we even measure their effectiveness?

We can, though it’s no easy task. Even so, overwhelming evidence tells us that we’re much better off with environmental regulations than we would be without.

Take, for example, air quality regulations. While the hazy summertime Atlanta skyline in the 1990’s compared with the blue one we see today seems to suggest an improvement, tracking down exactly what caused the change requires some sleuthing. Are we benefiting more from improved weather than cleaner cars? Utilities have moved away from coal to cheaper, cleaner-burning natural gas — do we have only the economy to thank? Are we just remembering it wrong?

To answer these questions, I worked with fellow researchers at Georgia Tech and Emory to play the what-if game. We used air quality measurements from a monitoring site in Midtown along with state-of-the-art computer models to investigate how Atlanta’s air quality would have changed if regulations put in place in the 1990s and 2000s had not been implemented.

Our what-if game told a clear story. Without cleaner cars on the road and emission controls on power plants, Atlanta’s air quality today would have been slightly worse than it was in the late 1990s. Even when accounting for changing weather patterns, concentrations of many dangerous pollutants in Atlanta’s air are up to 50% lower than they would have been without regulations. Strict rules on new cars and the dirtiest power plants have had big impacts, whereas requiring annual emissions inspections on cars owned in the city has affected Atlanta’s air very little.

We took it one step further.

Epidemiologists on our team found that air quality regulations prevented more than 55,000 emergency department visits related to heart and lung diseases in five Metro Atlanta counties between 1999 and 2013.

The rules benefitted the most people in the last two years in our study — 2012 and 2013 — and it’s likely that recent years have seen even larger benefits.

Our results show that air quality regulations have been a major boon to public and environmental health in Atlanta, and our results aren’t unique. Research groups across the country have found that our air is much cleaner now than it was before President George HW Bush expanded the scope of the Clean Air Act in 1990.

President Trump’s team has said that their motives behind dismantling environmental regulations are economic. They argue that the rules simply are not worth their costs. For example, in the proposal to repeal the Clean Power Plan — which would have reduced power plants’ contributions to climate change while simultaneously reducing emissions of other dangerous particles and gases — the EPA argued that the health and environmental benefits of the rule were inflated when it was originally proposed. Proponents of the rule have pointed out that the current administration’s evaluation uses flawed methods that understate the rule’s true monetary benefits.

Evidence from our study and similar studies argues for a more humanity-forward assessment of environmental rules.

Those 55,000 avoided emergency departments meant fewer trips to the hospital for people like you, me, and Atlanta’s school children. We know that cleaner air means fewer asthma attacks, runny noses, and heart attacks — surely, it’s worth investing in. Similarly, since we know contaminated water flows into communities downstream, it makes sense to limit what gets put into the water upstream.

Of course, environmental regulations are not guaranteed to produce their expected benefits. Plans for future environmental rules, therefore, should include a healthy dose of skepticism. Rigorous assessments of existing rules are a great place to start, and, given recent evidence of major successes, we should be heavily suspicious of attempts to weaken the regulatory structure that’s gotten us this far.

Our research was published by the Health Effects Institute on 19 April, 2018. The report is available here:



Luke Henneman

Air quality and health researcher arguing for scientifically sound policy.