Because NOx can travel hundreds of miles after it leaves a smokestack or tailpipe, the majority of what lands on the Bay and its watershed originates from outside the Bay states, according to computer models. The new air standards should reduce NOx emissions because it is a major contributor to the lung-damaging ozone pollution that forms on hot, sunny days when NOx and other pollutants mix in the air. In addition, NOx emissions can concentrate into tiny particles which will be regulated for the first time under the new standards because they are harmful to the lungs when inhaled. Such reductions would be similar to those already being implemented in a region from Northern Virginia through Maine to reduce chronic smog problems along the East Coast. But those reductions alone are not able to to fully attain ozone standards in the East because so much NOx drifts in from the Midwest.
Similar problems exist for Chicago and a few other areas.
OTAG also said the EPA should explore new standards for diesel engines. The EPA this summer is expected to set specific NOx emission levels for states based on OTAG recommendations. The states will have the flexibility to determine exactly how to meet those targets. The EPA has said in the past that most areas will be able to meet its new air standards through the implementation of the OTAG recommendations and the anticipated creation of a national low emission vehicle. Still, some areas would need to make additional reductions.