Thread by @WIRED

You already know air pollution is bad for your health, but 3 new studies show it’s way worse than previously imagined. Compelling evidence suggests it contributes to dementia—and the stats are so overwhelming many researchers believe it’s conclusive 1/
wired.trib.al/iISeL0T

The three studies each took place in different parts of the world, and all of them looked at years of data to determine the extent to which air quality can determine our health. The conclusion? It’s as bad as cigarette smoke 2/ wired.trib.al/iISeL0T

The most compelling study was in the US, where researchers used an EPA program that targeted counties across the country in violation of air quality standards. Residents of those counties saw their air quality improve at a faster rate than nearby peers 3/ wired.trib.al/iISeL0T

They found that annual exposure to an average of one more microgram of fine particle pollution per cubic meter of air (i.e. a clean vs polluted neighborhood) raised the typical US elder’s risk of dementia as if they had aged 2.7 additional years 4/ wired.trib.al/iISeL0T

In another study, researchers followed 130k older adults in London for several years. Those exposed to higher levels of air pollutants were significantly more likely to develop Alzheimer’s disease than their demographically matched peers 5/ wired.trib.al/iISeL0T

A 2017 study that followed adults in Ontario, Canada for over a decade found that those who lived closer to major high-traffic roads were significantly more likely to develop Alzheimer’s disease regardless of their health or socioeconomic status 6/ wired.trib.al/iISeL0T

There’s more research to be done, but at this point there appears to be a strong link between air pollution and dementia. Making matters worse, this evidence arrives alongside the alarming news that air quality is actually degrading in many US cities 7/ wired.trib.al/iISeL0T