Air pollution could increase your risk of developing Alzheimer's, Parkinson's or other neurological disorders, study suggests

The air you breathe each day could be harming your brain, a recent study suggests. 

The report, published Monday in The Lancet Planetary Health, found air pollution was significantly associated with an increased risk of hospital admissions for several neurological disorders, including Parkinson’s disease, Alzheimer’s disease and other dementia.

In the 17-year-long study of more than 63 million older U.S. adults on Medicare, scientists specifically looked at fine pollution particles called particulate matter of 2.5 microns in diameter or less. 

Xiao Wu, co-lead author of the study and a doctoral student in biostatistics at Harvard T.H. Chan School of Public Health, said these particles come from construction sites, unpaved roads, fields, smokestacks and fires.

“Most particles form in the atmosphere as a result of complex reactions of chemicals such as sulfur dioxide and nitrogen oxides, which are pollutants emitted from power plants, industries and automobiles,” he said.

These particles are considered safe by the U.S. Environmental Protection Agency’s national ambient air quality standards, so long as a person breathes in an average of 12 micrograms per cubic meter of air or less per day over the duration of a year.

But the long-term study calls that guidance into question. 

“Our U.S.-wide study shows that the current standards are not protecting the aging American population enough, highlighting the need for stricter standards and policies that help further reduce PM2.5 concentrations and improve air quality overall,” said Antonella Zanobetti, co-senior author of the study and principal research scientist in Harvard Chan School’s Department of Environmental Health.

Every five years, the Clean Air Act requires the EPA to review relevant science and update air quality standards if changes are needed to protect public health "with an adequate margin of safety," according to the agency.

“As a result of Clean Air Act programs and efforts by state, local and tribal governments, as well as technological improvements, the United States has made vast improvements in air quality," an EPA spokesperson said in a statement sent to USA TODAY. "During the Trump Administration, criteria air pollutant emissions have dropped 7% – the best air quality ever on record."

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The World Health Organization said exposure to fine particulate matter is estimated to have caused 4.2 million premature deaths worldwide in 2016. The agency says it can cause cardiovascular and respiratory disease, and cancers.

However, this is the first nationwide U.S. analysis that has linked fine pollution particles and neurodegenerative diseases, according to researchers from the Harvard T.H. Chan School of Public Health, Emory University’s Rollins School of Public Health and Columbia University’s Mailman School of Public Health.

The study follows research from the University of North Carolina Gillings School of Global Public Health published in February that found fine particulate matter was associated with depression and brain damage, including memory loss and accelerated aging especially later in life. 

Dr. William Vizuete, associate professor in the department of environmental sciences and engineering who co-led the UNC study, said while the new study may have been limited to an ensemble of air quality models that can only estimate levels of exposure, it puts into question whether current EPA standards are protective of an older population. 

"This new evidence seems to suggest that we may need to take a look at if we’re being protective of everyone," he said. "We need to look at the longer terms." 

The mounting evidence comes as wildfires continue to rage in Colorado, where the Cameron Peak Fire and Calwood Fire have torched more than 200,000 acres of land, forcing thousands to flee from their homes. This year’s wildfire season also ravaged parts of California and Oregon.

Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT. 

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