Something a friend said the other day stuck with me: “Cars aren’t the problem – it’s the big trucks that cause the smog on the highway.” We were discussing car emissions, as I had just done research about it for our last blog post. I figured there was some truth to what my friend was saying, so I decided to do some research.
As it turns out, we were both right.
Tractor-trailers are the heaviest vehicles allowed on highways in every state, and are generally used for long-distance journeys to transport goods. According to our research, these semi-trucks have diesel engines, which are more fuel-efficient and durable than gasoline engines, and lower-cost to operate and maintain. That, of course, comes with a price: They pollute much more than gasoline engines. The EPA’s Plain English Guide to the Clean Air Act states that “heavy-duty trucks and buses account for about one-third of nitrogen oxides emissions and one-quarter of particle pollution emissions from transportation sources. In some large cities, the contribution is even greater.”
But according to the research, diesel is the best option for these huge trucks: the EPA states the appeal of diesel gas “where the low stress, high efficiency cycle will lead to a much longer engine life and lower costs to operate. These advantages also help to make the diesel engine ideal for use in the heavy haul industry.”
While big trucks are legally permitted to emit as much pollution as a dozen cars, in reality many produce as much pollution as 150 cars. Statistics show that large, semi-trucks are the primary source of smog (smoke and fog), of poisonous chemical contamination, and of fine particle soot that causes our air quality to decline, an increase in allergies, and a drastic effect on the ozone layer.
According to the EPA, there are more than 210 million cars and light-duty trucks on the road in the US:
The types of cars people drive have changed greatly since 1970. Beginning in the late 1980s, Americans began driving more vans, sport utility vehicles (SUVs), and pickup trucks as personal vehicles. By the year 2000, these “light-duty trucks” accounted for about half of all new passenger car sales. These bigger vehicles typically consume more gasoline per mile and many of them pollute three to five times more than cars.
There is some light at the end of the tunnel, however. With the 2007 Highway Rule, the EPA created a rule that 2007-model year and later vehicles would reduce harmful pollution by more than 90 percent through strict emissions standards for diesel engines and cleaner, ultra-low sulfur diesel fuel.
The next time you find yourself in traffic surrounded by tractor-trailers, roll up your windows and turn your in-cabin air filter if you have one. Remember that you, too, can make a difference – whether it’s choosing a greener vehicle as your next vehicle or getting involved locally.