HISTORY OF VEHICLE EMISSIONS
The negative effects of the internal combustion engine on the environment and air quality have been a concern for many years. Today, more than 6.3 billion vehicle miles are driven every day. Emissions from mobile internal combustion engines (automobiles and light trucks) are mostly Water Vapor and Carbon Dioxide, but these engines also have produced over 50% of the air pollution in our atmosphere. About half of the ozone and nearly all of the Carbon Monoxide are attributed to these mobile sources. A typical vehicle emits about a half ton of pollutants annually, and a vehicle with defects or in poor condition emits many times that amount. Direct health consequences caused by vehicle pollutants include increased levels of carcinogens and irritants to eyes and respiratory and cardiovascular systems. In addition to concerns about pollution, there are also good reasons to conserve petroleum resources. The United States has less than 5% of the world’s population, yet we consume more than 40% of the world’s petroleum. Tuning, maintaining and repairing vehicles will not only reduce levels of pollutants but will also improve fuel economy and stretch petroleum reserves.
Pollutants emitted by gasoline powered vehicles include:
Carbon Monoxide (CO) is a colorless, odorless, poisonous gas that is produced by combustion in gasoline engines. It can cause dizziness, headaches, impaired judgment, and in large concentrations, death from oxygen starvation.
Hydrocarbons (HC) are unburned fuel molecules that either exit the tailpipe (leftover from incomplete combustion) or evaporate from the vehicle fuel supply or gas pump nozzle. Emissions during refueling have become a more significant source of HC as tailpipe emissions have been reduced. HC combines with Oxides of Nitrogen (NOx) in the presence of sunlight to form Photochemical Smog, which creates a brownish haze and contributes to respiratory problems and eye irritation.
Oxides of Nitrogen (NOx) are compounds that are produced when combustion temperatures in the engine’s cylinders exceeds 1400 degrees C (approx. 2500 degrees F). Above these temperatures, normally inert Nitrogen (N2) combines with Oxygen (O2) to form several different compounds which again contribute to Smog, respiratory problems and eye irritation.
Sulfur Dioxide (SO2) is a colorless gas with a pungent rotten egg odor. High sulfur content in the gasoline leads to SO2 production in the catalytic converter. It can cause respiratory irritation, heart problems, and increased risk of asthma.
Carbon Dioxide (CO2) is not toxic and not a pollutant, but it is considered a greenhouse gas and a major contributor to global warming. Much of the CO2 increase in the atmosphere is a result of burning gasoline in internal combustion engines – for every gallon of gasoline burned, about twenty pounds of CO2 are emitted to the atmosphere.