Air Pollution A Guide to the Illinois Vehicle Emissions Inspection Program Table of Contents Air Pollution Causes of Air Pollution Research indicates that approximately 3,700 premature deaths and thousands of medical emergencies are linked to air pollution in the greater metropolitan Chicago and East St. Louis areas each year. Carbon monoxide and hydrocarbons are the two main exhaust gases produced by the combustion process in gasoline-powered vehicles.
Carbon monoxide is a colorless, odorless, toxic gas.
It is a by-product of incomplete combustion. Carbon monoxide reduces the volume of oxygen that enters the bloodstream and can slow reflexes and causes drowsiness, impair judgment and vision and even death. Hydrocarbons are unburned fuel vapors. Vehicles are responsible for about 50 percent of the emissions that form ozone. It protects us from harmful ultraviolet rays that can cause skin cancer, cataracts and damage to our immune system.