The Dirty Truth About Idling Your Car

No Idling Children Breathing sign on the street

Every year, smog causes thousands of emergency room visits, costing our health care system millions of dollars to treat unnecessary respiratory illness. What’s worse is that about 9% of all non-accidental deaths are due to smog.

The chemicals in smog also put you at significantly higher risk for rheumatoid arthritis, autoimmune disease, cancer, brain damage, heart disease, lung disease/COPD and asthma.

What is Smog?

Ground-level ozone, or “smog,” is one of the most dangerous airborne pollutants.

Smog is made when nitrogen oxide (NOx), a by-product of burning fossil fuels like gasoline, combines with volatile organic compounds (VOCs) in the presence of sunlight, and becomes a colorless, odorless, gas.

Because of the role that sunlight plays in its production, ground-level ozone (or “smog”) is more prevalent during the sunny months, from about mid-May until mid-September, which is often called the “smog season.” But in urban areas, smog often happens year round.

Smog is Very Deadly to Children

Children are particularly vulnerable to smog because their lungs are still developing and they breathe faster than adults and inhale more air per pound of body weight. Children also spend more physically active time outdoors, and they are shorter than adults, which exposes them to more vehicle exhausts and heavier pollutants that concentrate at lower levels in the air.

In fact, in children, smog has been found to:

  • aggravate asthma, leading to more frequent and severe asthma attacks;
  • increase the number of respiratory infections;
  • aggravate and induce allergies;
  • increase school day absences; and
  • increase emergency room visits, hospital admissions and premature deaths.

Idling your vehicle is a major source of smog, and is particularly an issue at schools because many bus drivers and parents sit with their vehicles idling while waiting to pick up their children, creating a huge cloud of pollution for them to walk into as they leave the building.

This is compounded by the fact that smog is already at its daily peak at the time when most parents are picking up their kids.


It would be so much better on every level if bus drivers turned off the buses until they were ready to go, and parents parked their cars and met their children at the school door.

If you are going to be stopped for more than 30 seconds (except in traffic), it’s best to turn off your engine. Idling your vehicle for longer than 10 seconds uses more fuel than it would take to restart the vehicle, saving you money, too.

The following infographic from Sustainable America breaks down even further the major environmental and economic problems with idling your car.

Learn how to be idle-free, take the pledge, and get a free bumper sticker at

Idling Vehicle Facts

idling vehicle facts