This is an archived article that was published on sltrib.com in 2016, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.
With new federal regulations for vehicle emissions set to take effect this coming year, state officials are eager to remind residents of the impact their transportation choices have on Utah's air.
Vehicles are responsible for about half of the emissions that contribute to Utah's infamous wintertime-inversion episodes and to elevated ozone levels in the summer, said Glade Sowards, a policy analyst for the Utah Division of Air Quality. If everyone were to replace their old car with a new model, he said, Utah could reduce vehicle-related emissions by as much as 80 percent.
"The reductions that we're talking about, they're really substantial," Sowards said — larger than any other single action "we have been able to unearth."
Because of Utah's complex weather patterns and because vehicles aren't the sole source of emissions, Sowards said he couldn't say for sure a mass vehicles swap could end red air days in Utah. But "it would certainly help," he said.
New cars are sold with window stickers advertising their federal "smog rating." These ratings indicate, on a scale of 1 to 10, how much pollution the vehicle emits per mile driven.
A vehicle with a smog rating of 8, for example, produces 30 milligrams of pollution per mile. A 5 produces 160 milligrams per mile. A 10 represents an emission-free vehicle. Cars built to the Environmental Protection Agency's Tier Three emissions standards — mandatory for car manufacturers as of model year 2017 — have an average smog rating of 8, Sowards said.
Older cars built to Tier Two standards average a 5. That means new vehicles produce one-fifth as much pollution as many older models.
"For the average person, there's no one single thing you could do that would have a bigger impact on your emissions than getting a cleaner car," said Ari Bruening, chief operating officer at Envision Utah.
If you're already car shopping, choosing to buy a model with a higher smog rating won't typically cost much extra. The improved emissions systems on cleaner cars typically add less than $100 to the price of a new car, Sowards said.
But buyers may find that top-rated vehicles might not be the size they want or have the features they need. It's harder to reduce emissions from larger vehicles or from those with four-wheel drive, Bruening said. "But even if those are your needs, you can still compare to see which has the higher rating."
Those who plan to buy used cars can also shop for better smog ratings, Sowards said. Though used cars may not be sold with a sticker in the window, the vehicle smog ratings, estimated fuel economy and other statistics can be researched at fueleconomy.gov.
Residents who aren't in the market for a car can still take steps to reduce their impact on Utah's air, Bruening said. Emissions-conscious drivers should avoid idling, keep their car well-maintained and string errands together to reduce pollution.