How to Compare Car Exhaust to Secondhand Smoke

Both car exhaust and secondhand smoke have trace chemicals; a direct comparison is difficult. However, they both contain a large amount of carbon monoxide in their emissions. Comparing the amounts in equal sized samples can give an estimate of comparable deadliness.

Carbon Monoxide

• Carbon monoxide is an odorless and colorless gas created by combustion. Inhalation of this chemical reduces the body's ability to transport oxygen, especially to the brain. Poisoning can occur quickly, and a person can be overcome before realizing anything is wrong. Breathing high concentrations of it for extended periods is fatal. To measure the amount of carbon monoxide, particles per hundred is used; 1 percent means that one out of every 100 molecules is carbon monoxide.

Car Exhaust

• The amount of carbon emissions from an engine differs depending on circumstance. A clean, well maintained and warmed up engine can have emissions as low as 0.05 percent. On the other hand, a poorly maintained vehicle can have carbon monoxide emissions as high as 15 percent. High levels are rare other than engine warm-up periods, during which they can be dangerous.

Secondhand Smoke

• The carbon monoxide emissions from secondhand smoke are on average much higher than a warmed up engine. The emissions average between 1.5 and 4 percent, though this can vary widely depending on brand and individual cigarette.

Considerations

• You are more likely to encounter cigarette smoke in unventilated areas than you would car exhaust.