If you live in a big city, you only have to look at the hazy skyline on a hot, windless day to see that cars are bad for air quality. But all this traffic is an even greater problem if you have air pollution-related asthma. It's pretty clear this pollution can exacerbate symptoms and even cause an asthma attack.

Though many of us rely on cars every day, they can negatively affect asthma in more ways than one. If you frequently experience indoor asthma, sitting inside a car can be a trigger for you.

Luckily, getting rid of asthma symptoms doesn't mean giving up your car or moving to a town with a one-lane road. With a few simple strategies, you can minimize the effects of air pollution caused by our love affair with automobiles.

Cars, Air Pollution, and Asthma

According to Sumita B. Khatri, MD, the co-director of the Asthma Center at the Cleveland Clinic Respiratory Institute, the two main culprits that contribute to air pollution asthma are atmospheric ozone and particulate matter from car exhaust in the air. "Both pollutants can strain airways in asthma by increasing inflammation and susceptibilities to allergies and infections," Dr. Khatri says.

And the more cars on the road, the worse the effects can be. "In general, more cars means more particulate pollution in the air, so larger cities with more vehicular traffic are worse than smaller cities with less traffic," says Gary Weinstein, MD, chairman of pulmonology at Texas Health Presbyterian Hospital in Dallas. "In addition, summer tends to be worse than winter for air pollution, probably due to more driving, mowing, and other activities. Midday is worse than early or late in the day for the same reasons."

Not surprisingly, Los Angeles, Dallas, Houston, and Atlanta, in addition to several cities on the Eastern seaboard, are some of the worst places for air pollution, according to AirNow.gov, where you can monitor your local air quality.

When it comes to avoiding asthma symptoms related to air pollution, the best approach is to avoid being outdoors when air quality is at its worst. "Avoid doing outdoor activities or exercise from 10 a.m. to 2 p.m.," says Dr. Weinstein. "Early morning or late evening would be better. If those times cannot be avoided, consider doing exercise indoors, if possible."

Stopping Asthma in Your Car

Outside the car, it's easy to understand how exhaust fumes can contribute to asthma. But you might be surprised to hear that asthma can be a serious issue inside your vehicle, too. Whether it's pet dander, smoking, strong odors, dirt and debris, or particulate matter that travels into the car from outside, all of these factors can lead to experiencing indoor asthma in cars.

To protect yourself, Khatri recommends steering clear of your known triggers when in your car — don't allow friends to smoke, avoid taking your pet with you, and use non-offending air fresheners and cleaners if the harsh chemicals in commercial products irritate you. He suggests regularly wiping down all seats in your car with a damp cloth or using washable seat covers if pets must ride in the car.

When driving on high-ozone days, try using your air conditioner and keeping the windows up. Conversely, roll down the windows to bring in fresh air on a good air quality day.

Another helpful tip from Khatri to avoid this type of indoor asthma is to turn off the engine when you're idling — whether quickly parked or waiting for someone to come out of the doctor's office. "There's no disadvantage to stopping and restarting the engine if you plan on staying put for 30 seconds or more because it takes less fuel to turn it off and re-start it," she says. "This helps reduce ozone and particulate matter pollution for all."