Diesel Dilemma: Eco-Friendly or Eco-Foe?

After landing a new job three times farther from home than my last job, I had to begin looking for a more economical car. My 25 miles to the gallon—on a really good day—4x4 was not going to cut it anymore. Like many people, I didn’t have the funds to purchase a hybrid car, so I had to look into other options; at a price range of under $30,000, my options were severely limited. The best vehicle I could find got less than 10 mpg better fuel economy than my 4x4, and when I broke down the cost of the new car versus the slightly increased mpg, it didn’t save me anything.

At a loss as to what to do, I asked around. When a friend recommended a new diesel car, I scoffed at the idea, thinking I already knew enough about diesel. They convinced me to put aside my reservations until I knew more, and so my research began.

I was shocked to find that Volkswagen has brought new diesel engines to the United States that more than doubled the fuel economy I was used to getting. My newer model vehicle had been averaging 22 mpg and Volkswagen’s new diesel cars reported getting 42 mpg. Further research into customer reviews revealed they were getting much more than the advertised 42 mpg, and a friend who owned one confirmed this. But, I wondered, would double the fuel economy make up for how bad diesel was for the environment?

According to Air Quality cars with catalysts that run on petrol, or gasoline, have lower exhaust emissions of mono-nitrogen oxides (NOx) and particulates than diesel cars, but produce more carbon monoxide (CO) and hydrocarbon (HC) than diesel cars. But which is worse? According to the American Geophysical Union, an affiliate of the National Academy of Sciences, petrol vehicles dump more secondary organic aerosols into the atmosphere than diesel vehicles do. These particles cause severe health issues, including heart and respiratory problems. AGU also stated that research showed diesel vehicles only contributed to 20% of these particles, meaning petrol vehicles produce 80% of it. This news blew my assumptions about diesel out of the water, so to speak.

In researching my particular car choice closer (a new Jetta TDI), I found even more that pushed me toward a new understanding of diesel vehicles, and Volkswagen. In 2007, all new diesel vehicles sold in the United States were required to run on ultra-low sulfur diesel (ULSD) fuel. This new diesel has a sulfur content of 15 parts per million (ppm), compared to 500 parts per million in regular diesel fuel—the fuel you hear so much negativity about that caused black smoke, strong smell, and higher levels of NOx and particulates, due to the 500 ppm needed to produce it. Diesel vehicles have now become better for the environment simply because it uses less crude product to create fuel. The Jetta TDI specifically has a particulate filter in the exhaust system that traps harmful particulates, including NOx and HC.

So, does this information mean diesel is the better way to go? Not necessarily, but in this case, it was the better choice for me. Hybrids do continue to be the most economically and environmentally responsible cars on the market if you have the extra money to spend. However, companies are continuously working to improve the performance and environmental impact of the vehicles they manufacture. Hopefully in the future, purchasing a new eco-friendly car will be more affordable and efficient to the average household.


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Photo Credit: Photo by McCorkle Creations.


- Written by: Heather M.