Dementia has become a major public health concern around the world. Dementia risk factors are significantly different among countries. The number of new cases of dementia anticipated each year worldwide is almost 7.7 million, one new case every four seconds. There are 3.6 million (46%) new cases per year in Asia, 2.3 million (31%) in Europe, 1.2 million (16%) in the Americas, and 0.5 million (7%) in Africa. Latin American and Caribbean low and middle-income countries are at high risk. Air pollution is an important risk modifiable factor for dementia across the world, and the recent report of the Alzheimer’s disease continuum in children and young adults residing in Metropolitan Mexico City along with the presence of cognitive impairment in 55% of the young adult population residing in Mexican cities with fine particulate matter concentrations above the current USEPA annual standard of 12 μg/m³ makes this a severe public health problem in progress. It is imperative to keep generating epidemiological data on dementia worldwide and their relationship with air pollutants to improve the strategies to face all the challenges associated with dementia and Alzheimer’s disease in particular. Alzheimer’s disease is a fatal disease, we have no cure, and we ought to invest in protecting our citizens by intervening in modifiable environmental factors.