ENVIRONMENTAL DAMAGE

It took over 200 million years for the oil beneath the earth's surface to form. In the past 200 years, we have already used half of that reserve. If current rates of consumption continue, the world's remaining oil would be used up in 40 years.

Right now, two-thirds of the oil used around the world powers transportation vehicles, and half goes to passenger cars and light trucks. Being conscious of our fuel use will help to conserve resources for future generations.

Transportation involves the combustion of fossil fuels to produce energy translated into motion. Pollution is created from incomplete carbon reactions, unburned hydrocarbons or other elements present in the fuel or air during combustion.

These processes produce pollutants of various species, including carbon monoxide, soot, various gaseous and liquid vapor hydrocarbons, oxides of sulphur and nitrogen, sulphate and nitrate particulates, ash and lead. These primary pollutants can, in turn, react in the atmosphere to form ozone, secondary particulates, and other damaging secondary pollutants. Combustion also produces carbon dioxide, the primary greenhouse gas.

These environmental concerns about the country's transportation habits have been studied extensively. The tailpipe emissions from cars and trucks account for almost a third of the air pollution in the United States.

Although smog is produced by many factors, including sunlight, temperatures, winds and "basin" effects the air pollution caused by transportation is a major contributor. In their Sprawl Report 2001, the Sierra Club graded the car and truck smog in America's 50 largest cities using data from the EPA.

The area containing New York City scored best, believe it or not, with a grade of C+, creating 54 pounds of smog from cars and trucks per person per year. Twelve of the top 50 cities earned a grade of F, including, surprisingly, Louisville, Kentucky, which has 137 pounds of smog from cars and trucks per person per year.

The Clean Air Act of 1970 gave the U.S. Environmental Protection Agency broad authority to regulate motor vehicle pollution, and since then, emission control policies have become progressively more stringent. In addition, the EPA has published various fact sheets, such as "Your Car and Clean Air: What YOU Can Do to Reduce Pollution."

The EPA advocates some easy changes to transportation habits such as:

• Avoiding unnecessary driving by consolidating trips, telecommuting, carpooling, using public transit, and choosing clean transportation alternatives such as biking and walking.
  
  
• Maintaining your car properly, something that will not only reduce the car's emissions and enhance its performance but will extend its life, increase its resale value, and optimize its fuel economy.
  
  
• Driving your car wisely; whenever possible, avoid things like idling, stop-and-go driving, air conditioning, high engine loads, idling in cold temperatures, and spilling or overfilling when refueling.
  
  
• Exploring the use of alternative fuels instead of conventional gasoline
  

In many urban areas, motor vehicles are the single largest contributor to ground-level ozone, a major component of smog. Ground-level ozone is the most serious air pollution problem in the northeast and mid-Atlantic states.

Cars also emit several pollutants classified as toxics, which cause as many as 1,500 cases of cancer in the country each year. Auto emissions also contribute to the environmental problems of acid rain and global warning.

Pollution control measures have drastically reduced emissions per vehicle in the past 20 years. However, during that time the total miles traveled has doubled, resulting in higher levels of air pollutants in many parts of the country.

As we touched on before, motor vehicles generate three major pollutants: hydrocarbons, nitrogen oxides, and carbon monoxide.

• Hydrocarbons react with nitrogen oxides in the presence of sunlight and elevated temperatures to form ground-level ozone. It can cause eye irritation, coughing, wheezing, and shortness of breath and can lead to permanent lung damage.
   
• Nitrogen oxides (NO) also contribute to the formation of ozone and contribute to the formation of acid rain and to water quality problems.
  
  
• Carbon monoxide is a colorless, odorless, deadly gas. It reduces the flow of oxygen in the bloodstream and can impair mental functions and visual perception. In urban areas, motor vehicles are responsible for as much as 90 percent of carbon monoxide in the air.
  

Motor vehicles also emit large amounts of carbon dioxide, which has potential to trap the Earth's heat and cause global warning which we’ll address in the next section.

Cars release pollutants from the tailpipe as the result of the fuel combustion process, and from under the hood and throughout the fuel system when heat causes fuel evaporation. Evaporative emissions occur at these times:

• When outside temperatures on hot, sunny days cause a car's fuel to evaporate
   
• When the hot engine and exhaust system of a running car cause the fuel to become heated
   
• When the car is shut off and remains hot enough to cause fuel to evaporate
  
  
• During refueling, when gasoline vapors escape into the air from the gas tank and the nozzle
  

The greatest amount of tailpipe pollutants are released during the "cold start" phase, or the first few minutes it takes a car to warm up. Since a car warms up faster when it is moving, drivers are advised to limit warm-up time. Combining trips also decreases motor vehicle emissions since it reduces the number of cold starts.

Environmental damage caused by car emissions is a problem – there’s no doubt about that. But there is another very serious issue that comes from car emissions due to gasoline usage.

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