Research and analysis

Air pollution: cognitive decline and dementia

A report by the Committee on the Medical Effects of Air Pollutants (COMEAP).


Air pollution: cognitive decline and dementia

Request an accessible format.
If you use assistive technology (such as a screen reader) and need a version of this document in a more accessible format, please email Please tell us what format you need. It will help us if you say what assistive technology you use.


COMEAP reviewed nearly 70 studies in human populations (epidemiological studies) which looked at possible links between air pollution and a decline in mental ability and dementia in older people. They also considered studies which investigated how air pollution might affect the brain.

From this review, it can be concluded that it is likely that air pollution does contribute to these effects. The most likely way this occurs is through effects on the circulation. It is known that air pollutants, particularly small particles, can affect the heart and blood vessels, including to the brain.

COMEAP has not made recommendations on how to estimate the effects of air pollution on dementia. They think that more research will be needed before this can be done with confidence.

Recommendations have been made for further research which COMEAP believes would help develop the evidence on this important topic.

Updates to this page

Published 25 July 2022

Sign up for emails or print this page