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Reducing in-car pollution

/ 07:46 PM September 20, 2013

We don’t want to lower our car windows when we’re traveling because we know the air pollutants, which we have an abundance of in any busy street in Metro Manila, can really cause much harm to our health. But even if we have air-conditioned cars and the windows are tightly closed, we may still be at risk of exposure to particulate pollution—the black, sooty smoke produced by diesel engines and coal-fired power plants.

Do you notice that when you’re traveling for more than an hour in your car or when you get caught in the traffic, you experience symptoms like irritation of the eyes, nose and throat; dry coughing; chest tightness; and shortness of breath? You have that feeling of stuffiness even though the air-con is working just fine. Changing your car ventilation setting can help reduce the particulate pollution inside your air-conditioned car.

The best way


Putting your ventilation to “recirculate” is the best way to reduce exposure to all types of vehicle-related particulate pollution, according to Dr. Scott Fruin, an assistant professor of preventive medicine at the University of Southern California (USC), who is the senior author of a study published recently in the journal Environmental Science & Technology.

“Otherwise, an hour-long commute to work or school can double your daily exposure to traffic-related particulate air pollutants,” Fruin warned.

The researchers measured in-vehicle particulate pollution exposure in a wide range of car types and operating conditions.

Reduced pollution

By taking a typical car (5 to 7 years old) with the “recirculate” setting, in-vehicle pollution can be reduced from 80 percent of on-road levels to 20 percent for very small particles, and from 70 percent to 30 percent for larger particles. Car ventilation settings which bring in outside air practically produce the same level as that of on-road pollution.

If you want a better in-car ventilation, you may have to change your car every four years. As expected, particulate pollution levels are lower in newer cars. It’s also lower when driving at slower speeds and when driving on arterial roads instead of freeways.

The researchers noted that pollution levels are five to 10 times higher on highways than in other areas.

Another interesting finding was that leaving the windows closed for over 30 minutes or longer, with one or more passengers, raised carbon dioxide levels in cars. So it may be advisable to lower down the windows even just for a minute every 30 minutes, if one is driving for longer than half an hour with one or several other passengers in the car.


Making an effort to reduce in-car pollution may not be a major issue for those with healthy hearts and lungs. But heart and lung patients, older adults and children with lowered resistance are considered at greater risk from pollutant particles.

The health risk

When one has coronary artery disease, congestive heart failure and asthma or chronic obstructive pulmonary disease, increased exposure to pollutant particles can aggravate his/her medical conditions and might even trigger potentially life-threatening complications such as fatal arrhythmias (irregular heartbeats) and sudden death.

Several studies have already established a relationship between particle levels to increased hospital admissions and emergency room visits and even to death from heart or lung diseases. So there’s no doubt that short- and long-term particle exposures can really lead to serious health problems.

So, if simple measures like pressing or turning the “recirculate” knob, and lowering the window every 30 minutes to pull in fresh air into the car can significantly reduce the risk to particle exposure, then we should make them as must-do things during our regular commute to school or office, or when we do long drives for out-of-town trips.

That may just spare one from those unnecessary trips to the emergency room. Hopefully not to the funeral parlor.

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TAGS: air pollution, column, dr. Rafael Castillo, health and wellness, in-car pollution
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