
September is Idle Free Awareness Month! As the temperatures start to cool, and inversion season approaches, we wanted to share some information about vehicle emissions from idling and its impacts on indoor air quality.
Every morning, cars idle in driveways, streets, and school zones. Exhaust drifts indoorsâtriggering asthma, worsening allergies, and affecting everyone in your home and community.
Vehicle exhaust makes up about 50% of the air pollution in Utah during a typical winter day, and unnecessary idling of cars and buses contribute a significant amount of emissions released into the air each day. Thatâs why we encourage drivers to âTurn Your Key, Be Idle Freeâ!

â 4 Easy Actions to Reduce Idling Pollution
1ď¸âŁ Turn Off Engines & Avoid Warming Your Car
Waiting in line or while parked? Stop the engineâit only takes seconds. Just 10 seconds of idling uses more fuel that stopping and restarting your engine. Also, as cold weather approaches, avoid warming your car by idling. Start your car only when youâre ready to leave. Itâs a myth that you need to idle your car to let it warm up â it actually causes more wear and tear on your car and wastes gasoline. (Learn more about other common idling myths here.)
2ď¸âŁ Become Aware of Your Idling Habits
Exhaust builds up and impacts the air quality anywhere vehicles are idlingâschools, sidewalks, playgrounds, bus stops, building entrances, and even inside your car. Pay attention to your idling habits and how it impacts the air around you.
3ď¸âŁ Clean Indoor Air
Exhaust pollutants donât just stay outsideâthey can seep into nearby homes, apartments, and buildings, even through closed windows. If vehicles have idled near where you live, run your air purifier to help clean the air.
4ď¸âŁ Move More, Pollute Less
Active travel reduces stress, boosts focus, and eases pick-up/drop-off chaos. Consider alternative modes of transportation available to you.
Walking â Exercise, independence, lower carbon footprint.
Biking â Fun, daily activity, eco-friendly.
Park & Walk â Reduce congestion, get extra steps.
đ˘ ď¸Salt Lake City Idle-Free Initiative
Salt Lake City limits idling to 2 minutes. Why? Because poor air quality is a year-round public health concern in the Salt Lake Valley. Our unique geography makes it easier for that pollution to be trapped. Car exhaust doesnât just impact our outdoor air quality, it impacts our indoor air quality as well.
The Idle-Free Ordinance and initiative prioritize our communityâs commitment to improving local air quality. While some idling, of course, is necessary (like waiting at a traffic light, or for the health and safety of a passenger) there are many situations where we can all remember to turn the key and be idle free!
đ Learn more â Idle-Free Ordinance
â Questions About Improving Your Indoor Air?
If you have questions about using your air purifier or improving your indoor air, donât hesitate to reach out. đŹ Contact us at cleanairslc@slc.gov.
Missed the previous Indoor Air Quality newsletters? Read them on our blog here!