Average Emissions and Fuel Consumption I Motor Vehicles and Air Pollution I Automobiles and Ozone I Automobile Emissions I Links

Vehicles and the Environment
The emissions from millions of vehicles add up. These emissions are byproducts from the engine combustion process and from the evaporation of fuel. Studies indicate that ten to thirty percent of vehicles cause the majority of vehicle-related air pollution. Because exposure to vehicle pollutants can cause serious health problems, the U.S. Environmental Protection Agency has established air quality standards to protect our health.

Pollutants

Carbon Monoxide
Carbon monoxide is a colorless, odorless, poisonous gas emitted from the vehicle's exhaust as a result of an incorrect air/fuel mixture resulting in incomplete combustion. Carbon monoxide interferes with the blood's ability to carry oxygen to the brain, heart, and other tissues. Unborn or newborn children and people with heart disease are in greatest danger from this pollutant, but even healthy people can experience headaches, fatigue and reduced reflexes due to CO exposure.

Ozone
Ozone is the major component in what we know as smog at ground level. Ozone is not emitted directly into the air but is produced in the lower atmosphere as a result of chemical reactions between oxygen, VOCs, and oxides of nitrogen in the presence of sunlight, especially in warm weather. In the body, ozone reacts with lung tissue, causing inflammation of the lungs. Ozone can cause harmful changes in breathing passages, decrease the lungs' working ability, and cause coughing and chest pains. Even healthy people are found to be sensitive to ozone exposure.

Sulfur Dioxide
Sulfur dioxide is emitted when fuel containing sulfur is burned in diesel engines. Sulfur dioxide exposure constricts air passages, creating problems for people with asthma and for young children, whose small lungs need to work harder than adults lungs.

Nitrogen Dioxide
Nitrogen dioxide and related nitrogen oxides (NOx) are produced when fuel is burned at excessive temperatures. These compounds contribute to ozone formation and are a health problem themselves. The effect of NOx exposure on the respiratory system is similar to that of ozone and sulfur dioxide.

Lead
Lead content has been reduced in gasoline at the refinery. As a result, there is a significant drop in public exposure to outdoor lead pollution. Lead poisoning can reduce mental ability, damage blood, nerves, and organs, and raise blood pressure. Even small ingestions or inhalations of lead can be harmful because lead accumulates in the body.

Particulate Matter
Particulate matter includes microscopic particles and tiny droplets of liquid. Because of their small size, these particles are not stopped in the nose and upper lungs by the body's natural defenses but go deep into the lungs, where they may become trapped and cause irritation. Exposure to particulate matter can cause wheezing and similar symptoms in people with asthma or sensitive airways. Particulate matter can serve as a vector for toxic air pollutants

Toxic Air Pollutants
Toxic air pollutants such as benzene and formaldehyde are substances from automobile emissions that are known to cause or are suspected of causing cancer, genetic mutation, birth defects, or other serious illnesses in people even at relatively low levels. The chemicals can be inhaled directly or carried by small particles (dust or lint) into the lungs.