"The meta-analysis suggested that an increase in ambient PM2.5 concentration was strongly associated with increased depression risk in the general population, and the association appeared stronger at long-term lag and cumulative lag patterns, suggesting a potential cumulative exposure effect over time."

Humans have made 8.3bn tons of plastic since 1950. This is the illustrated story of where it's gone

Air Quality sensors

Air pollution threatens health in Beirut http://is.gd/aIff2m

Look at number 1.

probably a good read