Several separate studies regarding air pollution and disease, all published in July 2021, found correlative links between dementia and Alzheimer’s and the particulate matter (PM 2.5) content of the air where they live.

A study from the University of Southern California regarding women in the U.S. aged 74-92 found that a 10 percent reduction in ambient PM 2.5 in the area immediately around their home were 14 percent less likely to develop any form of dementia. A similar study, this one from France and regarding people over 65, saw a 17 decrease in the frequency of Alzheimer’s disease for every microgram reduction of pollutant per cubic meter of air. A third study, from North Dakota, saw a strong correlation of zip codes with average elevated amounts of PM 2.5 and the rate of hospitalizations and deaths linked to Alzheimer’s and other age-related dementia. All three studies correlated for confounding factors such as gender, race, and environmental but non-airborne pollutants.

“It’s already well documented that exposure to PM 2.5 is associated with cardiovascular and other diseases, but within the last few years the number of publications is rising on an increased risk for brain tissue,” said Yuliya Krauchanka, professor of surgery at the Duke University School of Medicine and a co-author of the North Carolina study. “But the brain is usually the most well-protected organ in the body, so it’s a very alarming situation when we see toxins sneaking in through this barrier.”

All three studies measured air pollutants as physical particles smaller than 2.5 microns, regardless of composition, so there is still plainly much to study in the topic, but they make it plain that any improvement on air quality will protect lives and quality of life. Half of the population of the planet live in places where the PM 2.5 numbers are rapidly rising. Further investigation of these findings is obviously urgent.

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