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When Idling Kills

By Dr. Kohar Jones

As I trudged through day-old snow towards my car in a cold Chicago winter, I called my Dad, a mechanical guru.  We kept talking as I slammed the car door shut, inserted the key into the ignition, and kept on chatting as cold air poured through the vents.

 “You gotta go!” he said, “no talking on a cell phone while driving.”

 “Nah, we’ve got a minute,” I said.  “I’m waiting for the car to warm up.”

 “Why?” he asked.

 “So it runs more efficiently,” I said.

 “That’s a fallacy,” he said. “The car’s a machine.  Machines don’t care if the engine is hot or cold. You’re just wasting gas.”

I asked the idling question of a friend who keeps track of air quality for the Environmental Protection Agency.  He confirmed my dad’s advice, and told me about the dangers of idling.  Idling cars send toxic emissions into the air (most dangerous for lung health are the fine particulates, of 0.1-2.5 micrometers in diameter).  Particulate matter, along with high ozone levels, are two of the most important pollutants that destroy air quality. Ozone is created when specific pollutants react in sunlight; chief among the pollutants are vehicular and industrial emissions.  The website shows local air quality conditions and forecasts.

 Your Air Quality



Unhealthy for Sensitive Groups


Very Unhealthy


 The CDC Morbidity and Mortality Weekly report on Health Disparities showed that air quality is worst in urban areas.  The demographic groups most likely to live in areas of poor air quality are the demographic groups who predominantly live in cities—people in the highest income category, people with the highest and lowest categories of education attainment (downtown vs inner city), Asians and Hispanics.

Living in an urban area, idling is hazardous to your health.  Fine particulate emissions from idling cars worsen asthma, bronchitis and existing allergies, are a likely human carcinogen, and increase the risk of death from cardiovascular disease.  In the state of New Jersey, for example, it is estimated that the pollution from idling cars kills hundreds of people each year, likely more than homicide and accidents combined.

New Jersey responded by setting new laws against idling, both in diesel trucks and passenger cars. Other states including Illinois are working on similar legislation.

An EPA brochure provides fascinating idling facts.

A pop quiz! True or false:

  • Vehicles that idle 10 minutes each day waste 29 gallons of fuel each year.  29 gallons of fuel at $3.50 a gallon would be more than enough money to buy $100 worth of groceries. 
  • An idling vehicle emits 20 times more pollution than one traveling at 30 miles per hour. 
  • Only 10 seconds of idling uses more fuel than turning the engine on and off.

All true! Along with a final fascinating tidbit:

“The best way to warm a vehicle is to drive it.”

Later that week, I pulled into an indoor parking garage, and noticed grey exhaust spewing from the tailpipe of the yellow clunker parked in front of me. The car idled and the exhaust spewed throughout the time it took to pull into my space, turn off the car, gather my bags, and emerge into the poisoned air.  The pollutants tightened my lungs and made me nauseous.  I wondered if the driver was attempting suicide, but didn’t see any hose leading to the driver’s window. The driver’s head was bowed.  Had the driver had a heart attack due to accidental carbon monoxide poisoning?

I knocked on the window, and the driver, a young woman, looked up.

“Are you okay?” I asked.

“Yeah, just warming up the car,” she said.

“I just learned you don’t need to warm up cars,” I told her, “turns out it just wastes gas.” (And destroys the environment and kills your neighbors, I wanted to add, but didn’t.)

“Thanks!” she said, and drove off.

We can change our driving habits to combat disease.  Together we can protect our environment, decrease fuel usage, and save lives (and money).  No more idling!

Check with your state’s department of environmental protection to see what regulations and guidelines are in effect for your state.

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