Outdoor air pollution has been widely studied and regulated for decades, but the quality of indoor air and its potential risks were little unrecognized until the early 2000s. Yet in temperate climates we can spend up to 90% of our time in closed environments (houses, schools, offices, transportation, etc.), where we may be exposed to numerous pollutants. The question of indoor air quality has therefore become a major public health concern across the globe.
Not only is air pollution bad for our lungs and heart, it turns out it could actually be making us less intelligent, too. A recent study found that in elderly people living in China, long-term exposure to air pollution may hinder cognitive performance (things like our ability to pay attention, to recall past knowledge and generate new information) in verbal and maths tests. As people age, the link between air pollution and their mental decline becomes stronger. The study also found men and less educated people were especially at risk, though the reason why is currently unknown.