SALT LAKE CITY — The winter weather, complete with its often hazy skies, is a reminder that once again lawmakers are taking up a variety of pollution-busting measures on Capitol Hill.

The bipartisan Clean Air Caucus is tackling measures that include boosting funding for continued localized air quality research, tougher penalties for smoke-blowing trucks and expanded emissions testing for diesel vehicles in Utah County.

Rep. Patrice Arent, D-Millcreek, said HB101 will rope in diesel vehicles for emissions testing in Utah County — an area of nonattainment designation for federal clean air standards.

The measure, which does not include the mandate for farm equipment, is part of the "low-hanging fruit" to decrease air pollution, but Arent says it will make a difference.

"Statically we have found that (diesel) vehicles are more likely to be out of compliance with testing," she said.

Arent pointed to 2017 testing in Weber County that found 19 percent of diesel vehicles tested there failed emission standards. Of those that failed, a significant percentage included evidence of tampering.

The study showed that diesel vehicles accounted for 44 percent of the nitrogen oxide emissions, but accounted for only 13 percent of the fleet, she said.

Arent said she believes she has support for her bill among her colleagues, especially since the Senate sponsor lives in Utah County and drives a diesel — Sen. Curt Bramble, R-Provo.

HEAL Utah is on board with the measure.

"We feel that all cars should be as clean as they can be," said Jessica Reimer, the group's air quality policy director. "There's no reason diesel vehicles should not be tested."

Lawmakers also want to step up penalties for motorists who buy kits to make their trucks spew clouds of pollution-filled smoke — which Arent says she has seen motorists do in particular when they are next to a Prius or a bicyclist.

"It's unfortunate," she said. "But it happens."

Members of the Clean Air Caucus are also pushing for $100,000 to continue the air pollution monitoring that is on done on TRAX and via helicopters in a study coordinated through the University of Utah.

During the four-year tenure of the caucus, Arent said it has introduced and passed more air quality bills in the history of the entire Legislature, but she acknowledged the task is far from over.

"There is still so much more work to do today," she said. "And we have a lot of lawmakers working on many air quality issues today because of how it important it is to everyone."

Gov. Gary Herbert's proposed 2019 fiscal-year budget includes $850,700 to help with an air quality division staffing shortage and continue localized air quality research.

Utah Clean Energy's legislative liaison Josh Craft said his organization is working closely with lawmakers to extend solar tax credits as part of a compromise agreement hammered out among Rocky Mountain Power, advocates and industry on rooftop solar.

Craft said the $1,600 tax credit for rooftop solar systems will stay in place the next couple of years, but advocates are pushing for a less rapid phase out than originally mandated under state law.

Utah Clean Energy and groups such as HEAL Utah also are working to promote and accelerate the current rate of electric vehicle adoption in the state.

The tax credit for electric vehicle purchases expired last year, and groups would like to see it restored.

Just as importantly, Craft said they will resist any attempt by lawmakers to institute an added fee for electric vehicles to recoup money lost via the gas tax.

As states' gas tax funds have failed to keep pace with road funding needs due to a variety factors — such as more fuel-efficient cars — states are looking for some way to replace those lost revenues.

"I credit the Legislature for trying to get out in front of the challenge and look ahead on how to fund its transportation and infrastructure needs," Craft said.

With the disputed boundaries of Bears Ears and Grand Staircase-Escalante national monuments now in the courts, public lands issues are likely to be much lower profile this session than in 2017.

But Rep. Mike Noel, R-Kanab, is sponsoring HB136 to prevent government lobbying of federal land designations unless it first has the endorsement of the Utah Legislature.

Noel's bill is in response to the now-defunct Mountain Accord's push for a federal land designation of about 80,000 acres in the central Wasatch Mountains.

The effort has been revised by the newly organized Central Wasatch Commission and is also being pushed by Save Our Canyons.

Noel says it makes little sense for Utah to allow such an effort to move forward unless it has buy-in from the state's lawmakers.

Senate Minority Leader Gene Davis, D-Salt Lake City, is sponsoring SB52, which says the state should have a preference for leasing land over selling it.

Davis says his bill is specifically aimed at state land disposals that could include the current prison property or the Utah State Fairpark.

Holding onto the land, as values of land continue to increase, will allow the state to "bank" savings over the time from leases rather than profit off a one-time sale, he said.

"I want us to set a good policy of long-term leasing of land," Davis said.

As Utah's population continues to grow and pressures mount on the already busy and crowded Wasatch canyons, Senate President Wayne Niederhauser, R-Sandy, is proposing variable, electronic tolling as one way to encourage carpooling and mass transit as traffic options.

Niederhauser bill, SB71, would streamline the process to have electronic tolling on Utah's roadways.

The Legislature may also get a chance to take up the controversial issue of man-caused global warming and climate change.

Sponsored by Rep. Ray Ward, R-Bountiful, HCR1 directs the state to consider climate change as it crafts energy policies and to commit to encouraging residents and businesses to save energy where possible.