It’s September. The school year is in full swing and every weekday morning and afternoon, countless parking lots and neighborhoods near schools are packed with cars. September also brings Utah’s Idle-Free Awareness month, which reminds Utahns that idling wastes gasoline and produces air pollution as we leave summer behind and head into the colder months.

Whether in the September heat or the February chill, many parents keep the car running while they’re waiting in school drop-offline to keep their car comfortable. But recent studies from the University of Utah have shown that outdoor air pollution can make its way indoors, which might impact students’ health, absenteeism and test scores.

What can school districts, principals and PTAs do? A new study in the journal Vehicles from U researcher Daniel Mendoza, Westminster College researchers Madelyn Bayles and Rachel Forrest and colleagues shows that a campaign at an elementary school reduced both the number of idling vehicles and overall idling time. Here’s how they did it:

• The Clean Air Committee at Bonneville Elementary School in Salt Lake City utilized the Environmental Protection Agency’s Idle-Free Schools Toolkit for a Healthy School Environment to organize an anti-idling campaign and invited researchers from the U and Westminster College to study the results of the campaign.
• After a focus group and a community survey, the school sent informational packets out to its community, including an idle-free window decal, a letter describing the school’s policy and a pledge form.
• The school incentivized returning the pledge forms and designated a school “Clean Air Champion” during afternoon announcements.
• The school displayed a flag outside with its color corresponding to the day’s air quality forecast.
• Some drivers who weren’t idling were rewarded with an anti-idling keychain or Utah Royals soccer tickets.
• Anti-idling artwork submitted by students was displayed as yard signs.

The results? The number of idling cars decreased by 17% after the campaign, and total idling time decreased by 37%. The school’s multi-pronged approach, the researchers say, may help schools reduce idling and improve both outdoor and indoor air quality.

Find the full study here.

A Salt Lake City ordinance prohibits idling longer than two minutes. Do your part to reduce idling—it’s as easy as turning your key.