After improving for the better part of a decade, air quality in the US is worsening again -- and could be associated with nearly 10,000 premature deaths and billions of dollars in damages, according to a new analysis of Environmental Protection Agency (EPA) data.
Fine particulate matter in the air Americans breathe fell by 24% between 2009 and 2016. But concentrations have increased by 5.5% in the last two years, and premature deaths associated with exposure to the dangerous particles spiked by 9,700 last year.
Those deaths represent $89 billion in potential damages, according to a working paper published Monday in the National Bureau of Economic Research by two Carnegie Mellon University economists.
While the potential links with early deaths and financial damages are alarming, there are other effects of declining air quality that are more difficult to quantify but are negatively impacting people's lives, the authors say.
"I think the thing that people often overlook and that we don't have great data on is the kid down the block who has asthma, and whose asthma is getting worse. The person who has emphysema for whom breathing is even harder," said Carnegie Mellon professor Karen Clay, who co-authored the paper. "Those peoples' lives are being made worse as well."
The authors say the causes of this slump in air quality need further examination. But they point to three contributing factors -- booming economic activity, increasing wildfires and less strict enforcement of EPA clean-air regulations -- as likely explanations.
The particles the researchers focused on are tiny and are called PM2.5.
They float in the air we breathe and measure barely a fraction of the diameter of a human hair. But despite their small size, the particles have been linked to serious cardiovascular and respiratory problems, especially in children and the elderly.
These particles are tied to certain kinds of economic activity, primarily the burning of natural gas to generate power and increased emissions from diesel vehicles. The paper's authors say their findings are consistent with broader energy consumption trends, like the continuing phase-out of coal-fired power plants in favor of natural gas.
The soot and ash from wildfires that have charred huge swaths of the Western US are also contributing to the declines in air quality but do not account for all of the reversal.
Relaxing environmental regulations has been a signature policy initiative of the Trump administration, from attempting to weaken nationwide fuel-economy standards to replacing President Obama's Clean Power Plan.
But the paper's authors caution that better data is needed on the impact that looser EPA enforcement and deregulation could be having on air quality.
The researchers found that enforcement fell from from 2013 to 2018, a decline that could be the result of more cities and towns meeting federal air-quality standards. But as pollution has increased in 2017 and 2018, researchers have not seen a corresponding rise in compliance actions from the EPA, Clay said.
"The thing that's surprising in terms of enforcement is that now that [pollution] has started to go back up, we might expect to see a response in terms of increasing enforcement activity," Clay said. "And at least the data we have so far don't suggest that."