The tests used to determine the findings were part of the China Family Panel Studies, which involved 20,000 people across the country between 2010 and 2014.
Above all, air pollution reduces liveablity of different cities, including the capital already ranked among the world's worst liveable cities for different reasons by different worldwide agencies.
"The fact that fine particle air pollution is a major global killer is already well known", said Joshua Apte, who led the study published in the journal Environmental Science & Technology Letters on August 22, by the American Chemical Society.
Language ability suffered more than mathematical ability and men were harmed more than women - likely because there are differences in how male and female brains work.
"The government should also respond to the increasing concerns on air pollution, in particular the hidden cost on intellect, which has not been recognised before", he said.
Chen noted that high air pollution was the likely cause of the loss of intelligence, as opposed to simply being a correlation.
In Beijing, the rich are specially designing their homes and buying appliances to filter out pollutants in their air and water, while poorer residents are stuck breathing in the unfiltered smog, affecting not only their health but also, according to the new study, their cognitive abilities. This reverse effect too was more pronounced in less educated men over the age of 64 whose verbal test scores increased by 9.18 points over three years.
In the research done recently, it was for the first time that data on air pollution and lifespan was studied together to examine the global variations and find out how they affect the overall life expectancy.
The green body said increase in number of patients with ailments like lower respiratory infections, lung cancer, chronic obstructive pulmonary diseases, cerebrovascular diseases (stroke) and ischaemic heart diseases prove that rise in pollution is impacting human health.
The study suggested that while the research findings were specific to China, it could shed light on other developing countries with severe air pollution.
The World Health Organization estimates 90 percent of the world's population breathes highly polluted air, with Africa and Asia being the most affected regions.