Since the Air Pollution Control Act of 1955, levels of pollutants have dropped dramatically and so have rates of related health problems. By rolling back environmental protections, the Trump administration could undo much of that progress. What would the health consequences be?
Air pollution is a hodgepodge of chemicals, but levels of airborne particles less than 2.5 micrometers in diameter, called PM2.5, are a good indicator of overall air quality. These particulates, made up of toxic metals like lead, iron and zinc, are a big component of emissions from vehicles and power plants, both of which would see weaker regulation under the Trump administration's policies. For example, revised rules for coal-burning power plants, announced on August 21, could cause an additional 1,400 deaths per year from increased PM2.5 emissions, according to the Environmental Protection Agency.
"We can increase air pollution and maybe save some jobs," says Karen Clay, professor of economics and public policy at Carnegie Mellon University. "But it's also going to kill people." Here's what's in store:
Increased rates of lung cancer and heart disease. In one study, each increase in 10 micrograms of PM2.5 per cubic meter of air—the difference between Manhattan and the Adirondack Mountains—was associated with a 25 percent increase in the risk of a heart attack, stroke or other cardiovascular event over an individual's lifetime. Risk of cardiovascular disease jumped by 76 percent.
Brain damage. Particulates enter the lungs and pass into the bloodstream, and they can travel up the nose and go through a thin barrier between the nasal cavity and the brain. They speed cognitive decline in the elderly and contribute to Alzheimer's disease and dementia—a 2017 study showed that living with high levels of air pollution nearly doubles risk of dementia.
Diabetes. Scientists followed 1.7 million veterans for over eight years and found that exposure to PM2.5 increases risk of diabetes, probably by causing inflammation that affects insulin regulation.
Childhood death and disease. Since children breathe faster than adults, they absorb more pollutants, relative to their body size. Exposure hampers neuropsychological development and is linked to memory and attention disorders, delinquent behavior and poor performance on intelligence tests. It increases the risk of death for infants from respiratory illness and sudden infant death syndrome. Exposure in utero is linked to low birth weight and premature birth. When a Pennsylvania power plant closed in 2014, low weight and preterm births in areas downwind dropped significantly.
Fertility. Poor air quality reduces fertility rates for both men and women. After each of eight coal or oil-burning power plants in California closed down between 2001 and 2011, fertility rates went up.
How quickly will these effects show up in the population? Experts say that depends on many factors. But rates of asthma could rise quickly, and brain disorders would likely take a few years.
