Most of our survey respondents received a written warranty, but only a third of the warranties covered both parts and labor. And once the work is completed, have your car's emissions checked periodically to make sure the exhaust system is doing its job. Among the pollutants cars release are hydrocarbons, nitrogen oxides and carbon monoxide. Hydrocarbons and nitrogen oxides react in the presence of sunlight to form ground-level ozone, a major component of smog. Ozone and smog irritate eyes, damage lungs and aggravate respiratory problems.
Carbon monoxide can be fatal at high levels.
At lower levels, it interferes with the blood's ability to carry oxygen to the brain and can slow reflexes and affect thinking.