Air pollution has been a major issue in the U.S for quite some time now. The number one cause of air polution is car exauhst emisions. Engine exauhst from a cars tailpipe shoots into the air we breathe ever so often. Limiting the use of cars would exponentially help reduce the amount of air poluition we have within the U.S today. Knowing this, our main concern as humans right now should be trying to limting car usage in order to reduce harmful greenhouse emissions that cause air pollution and smog.

In Vauban, Germany, citizens have give up their cars and have moved into an experimental upscale community where cars are not highly used. Even though car ownership is allowed, there are only two locations to park the vehichle and would cost $40,000 to buy the parking space. As a result, 70 percent of Vauban's families do not own cars, and 57 percent sold their cars in order to move into the experimental community. Media trainer and mother of two, Heidren Walter says:"When I had a car I was always tense. I'm much happier this way." Germany has already taken a first step in order to help reduce car emissions in the air. David Goldberg, an official of transportation for America states:"All of our development since world was II has been centered on the car, and that will have to change." In Europe, passenger cars are responsible for 12 percent of greenhouse gas emissions while the United States is responsible for up to 50 percent greenhouse gas emissions in some car-intensive areas.

On Monday in Paris, motorists with even-numbered license plates were ordered to leave their cars at home or suffer a 22-euro fine ($31). The same ban applied to odd-numbered license plates the following day. Sadly almost 4,000 drivers were fined and twent-seven people had their cars impounded. In the capital of France, congestion of smog was down 60 percent after five-days. Diesel fuel is the leading blame, since France has a tax policy that favors diesel over gasoline. Diesel makes up 67 percent of vehicles in France, compared to a 53.3 percent average of diesel engines in the rest of Western Europe, according to Reuters. Not only is Germany taking small steps in order to reduce air pollution by limiting cars but Paris is also doing the same thing to help reduce smog.

Not only is Germnay and Paris trying to limit car usage but so is Colombia. In Bogota, Colombia; there is a program they have in which millions of Colombians either skate, bike, hike or took public transportation in order to get to work for one day out of the entire year. The goal is to promote alternative transportatin and reduce smog. Violators would face a fine of $25. Businessman Carlos Arturo Plaza commented:"It's a good opportunity to take away stress and lower air pollution." Two other Colomian cities, Cali and Valledupar, have decided to join the event in order to help reduce car usage.

Now we finally reach the United States after hearing about Germany, Paris, and Paris in terms of trying to limit the use of cars. Michael Sivak, who studies the trend of car usgae in America and is a reasearch professor at the University of Michigan's Transportation Research Institute, reports:"What most intrigues me is that rates of car ownership per household and per person started to come down to two to three years before the downturn, I think that means something more fundamental is going on." Mr. Sivak's research has found demogaphic shifts in the driving populations that suggest that the trend may accelerate. There has been a large drop in the percentage of 16-39-year-olds getting a license, while older people are likely to retain their license at they age. A study last year has also found that driving by young people decresaed 23 percent between 2001 and 2009.

Limitng the use of cars is starting to slowy take its place within the United States, Germany, Paris, and even Colombia. Hopefully more and more people around the world will do their part in order to help reduce greenhouse emissions such as smog and air pollution.