Greater improvement in long-term air quality (AQ) in late life was shown to be linked with slower cognitive declines in older women. This novel finding reinforces the epidemiologic evidence of a relationship between air pollution and cognitive aging.

• Although studies have demonstrated that late-life exposure to outdoor air pollution represents a modifiable risk factor for dementia, there is inconsistent epidemiological evidence for cognitive decline.

• Epidemiological studies have shown that enhanced AQ may reduce mortality and improve respiratory health, reinforcing the evidence of an association between ambient air pollution and these health outcomes.

• Researchers used a US cohort of 2,232 older women followed up to 20 years, to determine if women residing in locations with greater AQ improvement exhibited slower decline in their cognitive function.

• AQ improvement was described as the difference in air pollution levels over 2 time points that were 10 years apart.

• Residing in locations with greater AQ improvement was found to be linked with slower cognitive declines in older women, equivalent to women who were 0.9 to 1.6 years younger.

• The links were identified to be similar across age groups, geographic region, education, Apolipoprotein E (ApoE) e4 genotypes, and cardiovascular risk factors.