People can easily inhale fine particulate matter (particles less than 2.5 micrometers in diameter) and absorb it into the bloodstream. Fine particulate matter is considered of greater risk than larger particles. The researchers found that the risk of psychological distress increased alongside the amount of fine particulate matter in the air. For example, in areas with high levels of pollution (21 micrograms per cubic meter), psychological distress scores were 17 percent higher than in areas with low levels of pollution (5 micrograms per cubic meter). Another finding: Every increase in pollution of 5 micrograms per cubic meter had the same effect as a 1.5-year loss in education. Credit: Underwood, Science 2017
