This fact sheet sumarizes the main evidences that link air pollution with Alzheimer's disease and other types of dementia. Dementia imposes a large burden on health and social care systems, and this burden will rise over the next decades. In Europe, a recent report by the WHO estimates the costs of caring for the 14.1 million people living with dementia in the European Region at EUR 392 billion or almost EUR 28,000 per person with dementia in 2019 (WHO 2019). A growing body of evidence supports that modifiable risk factors for dementia account for around 40% of the cases (Livington et al 2020), which could be prevented or delayed. In particular, air pollution is one of the well-established risk factors for dementia, at present accounting for more than 500,000 in the EU.