Asthma and Idling: A Bad Combination

Mel PeffersThis post is by Mel Peffers, a project manager in the Living Cities program at Environmental Defense Fund.

Today is World Asthma Day. Since car exhaust can lead to asthma as well as global warming, we thought it would be a good day to highlight the importance of not idling your car or truck engine.

What makes idling especially bad for health is that drivers tend to idle in gathering places – by sidewalks, schools, playgrounds, homes, and offices. Breathing in pollution close to the source is more dangerous than farther away.

Take a look at the evidence.

Tailpipe Exhaust May Cause Asthma

Tailpipe exhaust from both gasoline- and diesel-burning vehicles contains the pollutants that produce ozone when combined with sunlight and heat. Ozone occurs mostly during the summer months. A warming planet means more hot days, and thus more ozone.

Breathing in ozone irritates and inflames your lungs, and repeated exposure can reduce lung function. There’s a lot of evidence that ozone makes asthma worse. But the Children’s Health Study in California found evidence that ozone causes asthma. The study also found that children can suffer irreversible lung damage as adults from breathing smog.

On top of that, diesel exhaust contains particulate matter (soot). This has long been known to cause a variety of health problems, including aggravated asthma (see CARB report on health effects [PDF]). But as with ozone, there is evidence that diesel exhaust particles may cause asthma, and not just worsen it.

California kids aren’t the only ones to suffer from tailpipe-induced asthma. A 2005 NYU Medical Center study showed that asthma symptoms among children in the South Bronx doubled on high traffic days.

Conversely, reducing ozone can improve asthma rates. During the 1996 Summer Olympics in Atlanta, the city closed downtown to private cars for 17 days. During this time, daily peak ozone levels dropped more than a quarter and hospitalizations for asthma fell by almost one-fifth.

Fight Global Warming, Save Money

There’s no reason to idle your vehicle engine. As I explained my previous post:

  • Today’s engines don’t need a warm-up period.
  • If you’re stopped for more than 10 seconds, it uses more gasoline to idle than to restart.

Many cities, including New York, have laws against idling, but they’re rarely enforced. We need better enforcement, but we can make a difference with our own actions and behavior.

So in honor of World Asthma Day, switch off that idling engine. You’ll curb global warming pollution, save money on gasoline, and help everyone to breathe better.

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  1. Posted May 8, 2008 at 12:04 pm | Permalink

    Mel, I have wondered about idling diesel busses and trucks for years. Can you state (and document) a break-even point on that issue? I’ve often asked drivers why they run their trucks/busses. Many say “it’s better for the engine/mileage/etc.” On a related matter, why do police cars often leave their engines running. Surely, they can turn on the engine and still catch the crooks (or donuts)!

  2. Posted May 8, 2008 at 1:26 pm | Permalink

    I’m not Mel, but I can answer your question because Mel addressed this in her previous post.

    The 10-second rule originally came from the Canadian Office of Energy Efficiency. But the idling portion of their Web site is down until May 20.

    Their results were duplicated, however, by the American Society of Mechanical Engineers, which found that restarting uses the same amount of fuel as idling with the air conditioner on for 6 seconds.

    The EPA also did a study, looking at diesel engines specifically. They said the break-even point was three minutes. That’s more than 10 seconds, but still not very much!

  3. cannedguds
    Posted July 24, 2008 at 10:22 pm | Permalink

    My cousin’s son has asthma and it’s a bad thing because he is always exposed to smoke coming out from the motorcycle of his father! And to make things worse, his father was so irresponsible that he gives his son chocolates and things like that! what a jerk and he don’t listen to what we say to him regarding his son’s condition! anyway, thanks for this article! I’ll show this to him and maybe, just maybe, he will be awaken. Thanks again for sharing this! here’s something I would like to share to you and they are a bunch of personalized Christian checks . I’m sure you will love what you see here!

  4. alohacarrie
    Posted December 14, 2008 at 2:13 am | Permalink

    Oh yes, noxious fumes most certainly effect asthma symptoms if they are not the sole cause.

    Just read somewhere that you can save gas by turning off your engine if you are going to idle for more than 7 seconds.

    Glad there is a reason to stop poisoning the air we breathe.

    We’ve been discussing wheezing and asthma at

    Many blessings,

One Trackback

  • […] Environmental Defense Fund Says Stop Idling for World Asthma Day That’s “idle” as in your car, not your personal habits. Ozone’s bad for asthma so no news there, but in the face of everything we can’t change on our own as average citizens, this is a good, easy-to-implement contribution towards better air quality. […]