For a long time, air pollution has been associated with lung disease, heart disease, and early death. Other conditions related to air pollution include stroke, asthma, chronic obstructive pulmonary disease, and emphysema. A recent study conducted in China has shown that for those aged 75 and above, there are 1,166 early deaths for every 100,000 people.

Studies from three different parts of the world have linked air pollution to cognitive impairment, dementia, and Alzheimer’s disease. The first study was conducted by a team of U.S and Chinese scientists analyzing data from China. From this study, it was found that those who are exposed to polluted air have poor performance in both verbal and math tests. Poor performance was more prevalent in older individuals, especially for men and those with little education.

The second study was conducted by scientists from England on 130,978 adults ages 50 to 79 from 75 medical practices in greater London. The study was conducted between 2005 and 2013. From this study, 2,181 older adults were diagnosed with dementia. Out of the total, 39% had Alzheimer’s disease 29% with vascular dementia, while 32% did not have a specific dementia diagnosis

From the second study, it was found that adults in places with high air pollution concentration were at the highest risk of dementia. The risk of dementia in adults from places with a high concentration of air pollution was 1.4 times higher than places with a low concentration of air pollution. These findings were also found in those adults given an Alzheimer’s disease diagnosis.

In the third study, scientists from the University of Southern California and Harvard Medical School analyzed data from 998 women aged between 73and 87 who had both cognitive tests and MRI scans. The scientists discovered those in areas with a high concentration of air pollution showed two differences from those who were not from areas with a high concentration of air pollution.  In addition, those exposed to high air pollution showed a significant decline in cognitive abilities. They performed poorly when exposed to learning a list of words. Those in polluted areas showed more shrinkage in brain areas that shrink due to Alzheimer’s disease.

Anatomically, they showed more atrophy (shrinkage) in those brain areas that typically shrink due to Alzheimer’s disease.