An exhaustive new study has concluded it is likely air pollution contributes to older people’s diminished ability to remember, think and reason. The Committee on the Medical Effects of Air Pollutants reviewed nearly 70 previous studies of their effects on cognitive decline and dementia. It also examined some aspects of the earlier evidence. The authors say they” think there is a strong case for the effects of air pollutants on the cardiovascular system having a secondary effect on the brain.”