Researchers from the Yale School of Public Health, Peking University, and Beijing Normal University studied air pollution exposure and cognitive performance. Their research found a link between exposure levels and reduced cognitive ability. Dr. Xin Zhang from Beijing Normal University answered some questions about the study for CleanTechnica. (The other researchers involved in the study were Dr. Xi Chen of Yale School of Public Health and Dr. Xiaobo Zhang of Peking University.)

According to your study, how much did air pollution exposure reduce cognition?

Our study shows that chronic exposure to pollution lowered verbal scores on the tests and that the higher the pollution levels were, the more the scores dropped. On average, 13.23 units increase in 3-year exposure to high pollution levels resulted in a verbal test score reduction of 1.36 points for men and 0.91 points for women.

Why did you choose to study sulphur dioxide, nitrogen dioxide and particulates smaller than 10 micrometers in diameter?

These three air pollutants are main sources of air pollution in China and PM10 is the dominant air pollutant on most of the days.

What are some of the main sources of these pollutants?

There are various sources, such as industrial waste gas, vehicles and coal burning.

How did you monitor the math and verbal skills of about 20,000 people in China?

The China Family Panel Studies (CFPS) interviews around 20,000 people and gives them 24 standardized mathematics questions and 34 word-recognition questions to test their math and verbal skills.

How do you know exposure to the three pollutants correlates to lower verbal scores?

We compare the same individuals across two waves and find the increase in exposure to air pollution leads to reduction in verbal test scores.

Were math scores lower too?

The effect on math tests is more muted than that on verbal tests.

How can vulnerable populations better protect themselves from air pollution?

They can wear respirators, and stay indoors when air quality is bad.

Would it be better for some older people to live in rural areas where there is less air pollution if they are able to move?

Yes.

Would it be better for older workers who work outdoors to wear respirators to filter out air pollution, if they can?

Yes.

How important is that members of the public pay attention to public health alerts regarding air pollution?

The damage on cognitive ability by air pollution also likely impedes the development of human capital. Therefore, a narrow focus on the negative effect on health may underestimate the total cost of air pollution. Investment in cleaning up air pollution is not only good for health, but also for the intellect of society at large.