Air Quality - Smoking Vehicles
What is a “smoking vehicle”?
A smoking vehicle is a car or truck that has visible emissions (not including steam) coming out of its tailpipe. It is a violation of the Missoula City-County Air Pollution Control Program only if the emissions last for more than 5 consecutive seconds, and are coming from a gasoline-powered engine.
The Problem with Smoking Vehicles
A car with smoke coming from its tailpipe generates as much pollution as up to 28 well-tuned vehicles. A vehicle spewing smoke is not only unpleasant, it also makes the air unhealthy to breathe. The tiny particles and other pollutants in vehicle exhaust contribute to respiratory problems and to cancer risk. Everyone can be affected, but sensitive populations including children, the elderly and those with respiratory diseases are especially at risk. We all have a responsibility to maintain our vehicles so that air emissions are minimized. Cleaning up smoking vehicles will improve air quality so that Missoulians can breathe easier.
What Causes Tailpipe Smoke?
Tailpipe smoke is usually caused by incomplete fuel combustion or by engine oil being burned. Tailpipe smoke varies in color and composition. The color of the smoke can help pinpoint the source of the vehicle’s problem.
| Type of Smoke | Diagnosis | Probable Causes |
|---|---|---|
| White (lasting more than 5 seconds) Note: If white smoke appears only during the first few seconds of start up, no repair is needed. |
Coolant or water leaking into combustion chamber |
|
| Blue (lasting more than 5 seconds) |
Engine oil being burned |
|
| Black or Gray (lasting more than 5 seconds) Note: If black or gray smoke appears only during the first few seconds of start up, no repair is needed. |
Incomplete fuel combustion |
|
| Type of Smoke | Diagnosis | Probable Causes |
|---|---|---|
|
White (lasting more than 5 seconds) Note: If white smoke appears only during the first few seconds of start up, no repair is needed. |
Improper air/fuel mixture |
|
| Blue (lasting more than 5 seconds) |
Engine oil being burned |
|
| Black or Gray (lasting more than 5 seconds) Note: If black or gray smoke appears only during the first few seconds of start up, no repair is needed. |
Incomplete fuel combustion |
|
Smoke or Steam?
Most vehicles emit visible vapor, or steam, from their exhausts when cold-started during cold weather. This is the result of water vapor normally present in the exhaust gases condensing as it comes in contact with cold air. This vapor will normally become invisible once the vehicle reaches operating temperature. This water vapor is normal, and should not be mistaken for smoke. Visible water vapor will disappear after several seconds, but exhaust from a smoking vehicle will leave a haze in the air.
Diesel Engines
While the Missoula City County Air Pollution Control regulations prohibit visible emissions from gasoline-powered vehicles, they do not address smoke from diesel vehicles. This is partly because when this regulation was passed, before 1976, diesel engines tended to smoke. Even today, it is considered normal for diesel vehicles to smoke a little, especially under hard acceleration. But excessive smoke is not normal.
In a 2006-2007 air study, the health department found that diesel exhaust is responsible for over 4.6% of the air pollution in the valley during the winter months. Diesel exhaust, like car exhaust, consists of very small particles that are particularly harmful to human health. As a community we need to find ways to reduce this component of our air pollution. One way to do that is to keep the existing fleet of diesel vehicles running as cleanly as possible.
Performance Benefits
Excessive exhaust is a clue that something is not working properly. Since smoke can be caused by unburned fuel, repairs can yield savings of up to 13% at the gas pumps! Other benefits include better engine performance, higher resale value, and longer engine life. Action can prevent more costly, future repairs.
Prevention is the Key
Proper maintenance and operation of your vehicle will reduce the emissions of harmful air pollutants. In addition, keeping your vehicle in good repair results in improved engine life and lower maintenance and fuel costs. A well maintained vehicle should not emit visible exhaust.
Other Steps for Cleaner Air
By reporting smoking vehicles, you can help us clear the air. But even more than smoking vehicles, the shear number of miles we drive causes a large part of our air pollution in Missoula County. You can do your part for cleaner air by taking the following steps:
- Carpool or ride the bus.
- Bicycle to work.
- Leave your car home once a week.
- Join Missoula in Motion’s Way to Go! Club. (www.missoulainmotion.com)
- Don’t let your engine idle unnecessarily.
- Drive smoothly – avoid jackrabbit starts and stops, which use up to 50% more gas than smooth starts.
- Plan ahead to combine trips.
- Whenever possible drive to a central location and park, then walk to your various destinations.
- Change your oil and oil filter regularly.
- Keep your tire pressure and alignment correct – low tire pressure can waste up to 5 % of a tank of gas.
- Change your fuel filter and air filter according to manufacturer’s recommendations.
- Monitor hoses, wiring and belts.
- Give your vehicle regular tune-ups according to manufacturer’s recommendations.
- If a warning light comes on, find out why and fix the problem.
- If you notice tailpipe smoke coming from your vehicle, get it checked out and. if necessary, fixed.
