New city ordinance aims to curb truck emissions, but we all can fight air pollution.

A new city ordinance only applies to large vehicles, but all can help combat air pollution.

Trucks idled for nearly 4 million hours at Port of Houston facilities in 2007, according to the website of the Environmental Defense Fund. Idling happens when a driver leaves a vehicle’s engine running while it’s parked.

Idling tailpipes spew out pollutants and create unhealthy smog and soot. These pollutants have been linked to serious human illnesses, including asthma, heart disease, chronic bronchitis and cancer. Children, the elderly and those with asthma and other chronic health problems are especially vulnerable to the health dangers of exhaust.

On Wednesday, Houston City Council took a needed step to combat air pollution. Now, drivers of vehicles weighing more than 14,000 pounds, or seven tons, can spend only five minutes idling.

The ordinance exempts vehicles sitting in traffic jams, military vehicles and various vehicles that must run heat or air conditioning for health and safety reasons.

Houston has multiple idling trouble spots in addition to our port. Buses drop off children at museums and often sit idling for hours, according to officials at the Museum Park Super Neighborhood Association.

The goal of the ordinance is voluntary compliance, but it’s not without some teeth. The Houston Health Department will “enforce the ordinance by issuing Notices of Violation for the initial violation and citations to repeat offenders,” according to Daisy D. James, acting bureau chief of the Houston Health Department.

The regulatory framework is stronger than it sounds. Both Dallas and Austin have adopted ordinances that limit idling time to five minutes.

Once truckers and others become aware of an anti-idling ordinance, many comply, according to a 2013 Capital Area Council of Governments survey. “We know from experience that these ordinances have high voluntary compliance rates — as much as 80 percent,” according to Adrian Shelley, executive director of Air Alliance Houston.

But the city must get the message out. “Lots of companies, school districts and Houston Metro have some sort of anti-idling policies in place. We’re trying to stop the bad actors from idling excessively,” according to Laura Spanjian, director of the Office of Sustainability for the City of Houston.

To that end, the city needs to reach out to large fleet owners, trucking associations and owners of truck stops. Signs about idling laws should target specific areas such as schools, hospitals, hotels and gas stations.

While the law only applies to large vehicles, all of us can help.

When you pull over, turn off your engine right away. Everyone has something to gain by reducing needless idling.