Of course, air pollution has negative impacts on human health, but does it also lead to an unproductive workforce? It seems that way:

Researchers found that a 10 ppb parts per billion change in average ozone exposure results in a significant 5.5 percent change in agricultural worker productivity. “These estimates are particularly noteworthy as the U.S. EPA is currently moving in the direction of reducing federal ground-level ozone standards,” said Dr. [Matthew] Neidell, PhD. This past September President Obama said he would not support a proposal by the Environmental Protection Agency to tighten the federal ozone standard because it would pose too heavy a burden on businesses…

via How air pollution impacts worker productivity | SmartPlanet.