Due to this, it's indoor pollution that we should start focusing on, rather then outdoor pollution. (educationbusinessuk.net)
In many cases, the level of indoor fine particle pollution measured was twice as high as the accepted standard for outdoor pollution established by the EPA. (jhsph.edu)
Agriculture is the leading source of outdoor pollution — related premature mortality in the eastern United States, Europe, and in countries such as Russia, Japan, and Turkey, the researchers found. (sciencemag.org)