"Transportation sources are the source for about 40 to 50 percent of that," said Kip Billings, with the council staff.
Andrew Gruber, executive director of the council, said bad air has direct financial implications.
"The ultimate hammer that the federal government has if we ultimately aren't able to meet their standards, is affecting our federal transportation dollars, for roads and transit," Gruber said.
John Njord, executive director of the Utah Department of Transportation, said such sanctions could halt using federal money for any projects to increase road capacity such as adding lanes, or building new roads and allow using money only for maintenance and safety.
Billings said the council is providing data about pollution from transportation to the Utah Division of Air Quality as it is finalizing a plan this year on how to cut PM 2.5, and hopefully attain standards by 2019 if the state can obtain an extension until then. It led to a raft of questions from officials about whether the standard will be met, and what the consequences of not doing so could be. Council staff said much of that is, literally, still up in the air and yet to be resolved.
But Billings said plans under development so far will reduce vehicle emissions by 50 percent by 2019 compared to 2008 levels, mostly from "improved emissions standards on vehicles that operate on the road, emissions testing programs … and certainly investment in transit that takes a lot of those vehicles off the road."
The council recently adopted a new 30-year transportation plan that shifts away from past emphasis of building major new highways more to adding more mass transit including far more bus rapid transit and trying to encourage growth of "town centers" where people can easily walk, bike or take transit to work, shopping or recreation.
While a large part of that shift aimed at reducing traffic congestion, the council noted it also reduces air pollution and may be a key part of meeting pollution standards.