For most people, your car is your most valuable possession. Your vehicle helps you pay the bills by getting you to and from work. It’s reliable. It’s convenient.
But, it can also be an air pollution nightmare.
Vehicular traffic is the leading source of air pollution in most U.S. cities, 
according to the U.S. Environmental Protection Agency (EPA). Although you may not be able to see it, your car’s tailpipe pumps out pollutants such as carbon monoxide, hydrocarbons and oxides of nitrogen.
Hydrocarbons and oxides of nitrogen react on hot, sunny days to form ground-level ozone. During the summer, high levels of ground-level ozone make it difficult for many people to breathe.
That’s the bad news. The good news is that there are a variety of steps you can take to make sure your car isn’t a pollution machine.
Maintain your vehicle on a regular basis.
When a vehicle is not properly maintained, its pollution control devices will eventually fail, causing increased emissions. To avoid releasing excessive emissions into the air, follow the recommended maintenance schedule listed in your owner’s manual. Preventative maintenance tips are also available through the Gateway Clean Air Program.
Is your “check engine” or “service engine soon” light on? Responding quickly to this malfunction indicator light can save you money! The light notifies you when something in the engine management or emissions control system has failed or deteriorated. Early diagnosis and repair can prevent more costly repairs, such as replacing a catalytic converter. Responding to the malfunction light in a timely manner will prevent excess vehicle emissions, which improves overall air quality in the region.
Think fuel efficiency.
The less fuel you burn, the less pollution comes out of your tailpipe. Over time, a fuel-efficient vehicle will save you money in refueling costs. When shopping for a new vehicle, compare the gas mileage ratings of several vehicles. More information is available on the EPA’s Web site at www.epa.gov/autoemissions/.
If your current car is a gas-guzzler, there are ways to improve its gas mileage. Remove unnecessary weight from your vehicle – leave the golf clubs in the garage; take the bag of sand out of the bed of your truck as soon as the ice disappears. Accelerate slowly, and drive at a steady speed. You can improve your gas mileage about 15 percent by driving at 55 mph rather than 65 mph. Reduced gas mileage is an indication that something might be wrong with your vehicle. Take it to a repair shop for diagnosis and repair.