While all cars contribute to pollution as they emit CO2 (even the electric ones, though in insignificant amounts) not all of them do it the same way. It’s easy to determine that an electric car or a hybrid, contaminates much less than one that burns fossil fuels. But things get more complicated when we analyze the differences between gasoline cars and diesel vehicles.
Gasoline vehicles principally emit carbon monoxide, nitrogen oxides, hydrocarbons and lead compounds. For their part, the vehicles that use diesel emit solid particles in the form of soot that gives rise to black smoke, unburned hydrocarbons, nitrogen oxides and sulfur anhydride from the sulfur contained in the fuel. They contaminate in a different way and in different proportions, which is why it is complicated to determine which of the two fuels contaminates more. Another factor is the age of the vehicle.
At first, diesel vehicles contaminated much more than those powered by gasoline, which resulted in restrictions against these vehicles imposed in major cities all over the world. But with new filtering techniques in diesel motors, the difference is minimal. Nowadays a gasoline car and a gas oil car of the same characteristics contaminate more or less the same, though in different ways. The diesel cars emit less CO2 than gasoline cars, but they continue to emit a greater number of other contaminants, although not with as great a difference as before.
To sum up: these cars contaminate in different ways, and in different proportions
This makes it hard to determine which is the one that contaminates the most
Another factor is the age of the vehicles (the old diesel ones contaminated much more than the new ones)
The least contaminating option is a 100% electric vehicle. But not even this technology is totally clean. This is because, above all, the energy used to produce the battery. According to the Guide to automobile emissions created by Arval (a Spanish renting company) and based on data from the European Environment Agency, some 51% of the CO2 emissions of an electric car are generated in its manufacture. But where does the remaining 49% come from?
According to the European Environment Agency, a middle-sized gasoline car emits an average of some 140 grams of CO2 per kilometer. With an electric car of the same characteristics, the figure is between 60 and 76 grams of CO2, or between 47% and 58% less. With a plug-in hybrid car, the reduction is 36%. It’s not that these vehicles emit CO2 through their exhaust pipe when moving, but that the contamination is generated in producing the energy necessary to charge their batteries.
When it comes to determining how much a vehicle is going to contaminate, we must take into account what kind of fuel it uses and, especially, how old it is. The Spanish Association of Automobile and Truck Manufacturers (ANFAC) notes that 80% of the vehicular contamination produced in a country like Spain comes from just 20% of the total of its vehicles: the oldest ones. And it adds that 100 current vehicles contaminate less than just one from the 1970s.
In the European Union, vehicles are responsible for 25% of the emissions of carbon monoxide and for 66% of the nitrogen oxides. Reducing the emission of the most contaminating vehicles and implanting more electric cars is thus essential for reducing these percentages.
