Aaron Reuben, writing in Mother Jones:
Of all the new research, three studies in particular paint a stark picture of the extent to which the quality of our air can determine whether we will age with our minds intact. In one from 2018, researchers followed 130,000 older adults living in London for several years. Those exposed to higher levels of air pollutants, particularly nitrogen dioxide and fine particulate matter released by fossil fuel combustion, were significantly more likely to develop Alzheimer’s disease—the most common kind of dementia—than their otherwise demographically matched peers. In total, Londoners exposed to the highest levels of air pollution were about one and a half times more likely to develop Alzheimer’s across the study period than their neighbors exposed to the lowest levels—a replication of previous findings from Taiwan, where air pollution levels are much higher.
Another, a 2017 study published in the Lancet, followed all adults living in Ontario (roughly 6 and a half million people) for over a decade and found that those who lived closer to major high-traffic roads were significantly more likely to develop Alzheimer’s disease across the study period regardless of their health at baseline or socioeconomic status. Both of these studies estimated that around 6 to 7 percent of all dementia cases in their samples could be attributed to air pollution exposures.
Those studies from Canada and the UK are certainly intriguing. But the most compelling, and least reported on, study comes from the United States. It was also, incidentally, inspired by our previous reporting.