The new standards would replace ozone regulations implemented by the Bush administration in 2008 that were deemed so weak as to be harmful to people's health, reports the New York Times.
Officially, the proposed standards limit the amount of ozone a person could be exposed to in a given area over eight hours: between 0.060 and 0.070 parts per million.
Regions with the worst smog pollution -- most of the Northeast; southern and central California; greater Chicago and greater Houson -- would be allowed extra time to comply.
The EPA also proposed a secondary, seasonal standard to protect trees and plants from the damaging effects of ozone, which rise in the summer and travel out of cities and into more heavily wooded areas.
Some big businesses argue that the new standards would be mostly ineffective and impose expensive costs that would be passed on to the consumer. Some environmental groups claim that the resultant reduction of health care costs would offset the sticker price of the proposed regulations.
For now, the EPA will take public comment on the proposal for 60 days. It expects to issue a final rule in August. By the end of 2013, states are required to submit plans showing how areas not in compliance will be brought into compliance, and the new rules are proposed to be phased in between 2014 and 2031 according to the severity of the area's smog levels.