Air pollution that spews from climate change-fueled wildfires, fossil fuel-burning power plants, artificial intelligence-generating data centers and gas-guzzling cars may be making you forgetful, a new study shows.
People with the highest levels of exposure to the microscopic particles over nearly 20 years scored lower on memory tests asking them to remember facts, words and general knowledge than others exposed to lower levels of pollution, researchers at U.C. Davis Health and the health care company Kaiser Permanente said Wednesday.
The results were similar to what researchers would expect from 10 years of normal aging and affect semantic memory: a crucial type of memory for everyday life.
“Semantic memory is essential for communication, comprehension and navigating everyday life,” the study’s senior author Kathryn Conlon, an associate professor in the UC Davis Department of Public Health Sciences, explained in a statement.
“Our findings suggest that long-term exposure to air pollution doesn’t just affect physical health — it may also shape how the brain ages, particularly in ways that matter for independence and quality of life,” she said.
There wasn’t the same impact for all types of memory.
Tests of verbal episodic memory, or the ability to recall certain events and experiences, and executive function, which helps with focus and remembering instructions, did not show an impact related to PM2.5 pollution, the type emitted from coal-burning plants, vehicles and industrial sources.
The researchers say that suggests there are declines in specific and distinct areas of memory, rather than to a person’s overall intellect.
The data for the study came from Kaiser Permanente’s 2017 Study of Healthy Aging in African Americans, including the majority of the study’s 750 adult participants who live in California’s Bay Area.
The researchers worked out the participants’ level of exposure to the pollution by determining estimated levels at their homes over the course of 17 years.
They assessed their cognitive performance using tests at the five, 10 and 17 years marks.
Disproportionate disease
Black Americans are twice as likely to develop Alzheimer’s disease and other forms of dementia compared to their white counterparts, according to the Alzheimer’s Foundation.
Past research shows the group has more risk factors for the disease, like diabetes and high blood pressure, and people of color disproportionately live in areas most affected by pollution.
Black Americans have a higher risk of premature death in these communities, the American Lung Association reports, and show higher rates of cognitive impairment likely because they are not seeking treatment until the disease advances, Alzheimers.gov explains.
“Many Black older adults tend to seek medical treatment when they encounter neuropsychiatric symptoms such as hallucinations, delusions and personality changes, but delay help for memory problems, which are often viewed as a normal part of aging,” the site says.
A longstanding modifiable harm
The new research also builds on years of past research showing the possible harms of PM2.5 particulate matter, including an increased risk of premature death, cancer and cardiovascular disease.
Past studies had also tied air pollution to more dementia cases and worsened Alzheimer’s disease. Some research has identified a modest link between wildfire smoke exposure and dementia.
A study from earlier this year found that air pollution raised the risk of amyloid plaques – clusters of proteins that are a hallmark of Alzheimer’s disease – in older Americans with cognitive impairment.
“Understanding environmental contributors to cognitive decline is critical for addressing disparities in dementia risk,” Rachel Whitmer, co-author of the new study and the co-director of the Alzheimer’s Disease Research Center at UC Davis Health said. “Air pollution is a modifiable exposure. That makes it a powerful target for prevention — both at the individual level and through public policy.”
People can reduce their risk of exposure by limiting outdoor activity on days with high air pollution levels, using air filters indoors, keeping windows closed and avoiding exercising near busy roads.
