Cold starts

By Ashley Miller

Tips on how to avoid that moment when cars produce the most pollution

Did you know that 75% of the pollution coming from your tailpipe occurs in the first 50 seconds your car is running? In fact, 90% of the VOC pollution and 60% of the NOx pollution your car will spew while driving is emitted within the first 50 seconds.

Cold starts are a major problem when it comes to emissions from passenger cars and trucks. A cold start is exactly what it sounds like: starting your car when its engine is cold. Because of our cold climate, this is especially troublesome for the air quality challenges we face in Utah.

The emissions produced in that first 50 seconds during a cold start can equal the emissions a newer car will produce when traveling roughly 300 miles. Remember, we care about this because VOCs and NOx are precursor pollutants that lead to the formation of both wintertime particulate pollution and summertime ozone that plagues areas of Utah.

No, this doesn’t mean you should idle to keep your engine warm. Idling emits completely unnecessary emissions that should be avoided whenever possible. This is especially true for greenhouse gas emissions. Burning more gas by idling instead of turning your engine off directly results in more greenhouse gas (and other air pollution) emissions.

And no, this doesn’t mean you should “warm up” your car by letting it run in your driveway or a parking lot before taking off.

The fastest and most efficient way to warm your engine is by driving. Remember, a warm catalytic converter will do what it was designed to do. A good catalytic converter can reduce your car’s emissions by up to 99% once its operating temperature is reached. So don’t idle!

What you can (and should) do to reduce cold start emissions
1. Avoid driving all together if possible. Walk, bike, skate, scoot. Whatever works for you.
2. If you ride public transit, good for you! You’re certainly doing your part to reduce vehicle emissions. But do you drive to a park and ride or to Trax? Avoid this if you can. That way you avoid two cold starts each day.
3. Trip chain. Consider running your errands during your commute instead of making multiple trips each day. Drive to your farthest destination first and work your way back home. This way your car’s engine will have less time to cool down between stops.
4. Carpool with friends and pick them up at home. If you pick your friends up at home, rather than all of you driving to a parking lot, you’ll reduce that many cold starts every day.
So make yourself an early new year’s resolution and see how many cold starts you can avoid each day!

Ashley Miller, J.D., is the vice-chair of Breathe Utah. She is also the vice-chair of Utah’s Air Quality Policy Advisory Board and a member of the Salt Lake County Environmental Quality Advisory Commission.

This article was originally published on September 30, 2019.