Which is more polluting to the environment, diesel or gasoline?

If you look at the European automobile exhaust emission regulations, you will know that diesel vehicles actually have lower emissions and are more environmentally friendly than gasoline vehicles. To discuss emissions, we should not only look at particles, but also look at hydrocarbons, carbon monoxide and nitrogen oxides. In fact, diesel engines are cleaner and more efficient than gasoline engines. Before the fourth stage of the European automobile exhaust emission regulations, the particulate emission of gasoline engines was not explicitly restricted, indicating that the particulate emission of diesel engines is indeed more serious than that of gasoline engines and must be controlled. However, with the appearance of GDI direct injection gasoline engine, the particulate pollution of gasoline engine has also attracted people's attention. In Euro 5 emission standard, it has been clearly stipulated that the PM emission of GDI gasoline engine should not be higher than 0.005g/km, which is equivalent to the PM emission limit of diesel engine. Gasoline and diesel are linked to PM. Let's look at other pollutants. The CO and HC emissions of diesel engines are obviously lower than those of gasoline engines, but the NOx emissions are higher than those of gasoline engines. Of the four major pollutants, 2.5: 1.5, diesel engine won. Don't forget carbon dioxide, the chief culprit of climate change. If you consider the indisputable fact that the average thermal efficiency of diesel engine is higher than that of gasoline engine, do you still think that the emissions of diesel engine are higher than that of gasoline engine? In addition, diesel engines before Euro III can meet emission regulations without using exhaust climate treatment system, while gasoline engines need three-way catalytic system to meet emission regulations. In the future, GDI will become the mainstream trend of gasoline engines, and how to solve the particulate emissions brought by GDI has also been formally put on the agenda. For diesel engines, with the continuous increase of high-pressure rail pressure and the improvement of multi-pole supercharging, DPF, EGR, SCR and other technologies, diesel will increasingly become a clean and efficient energy source. (Note that I didn't say that diesel is a "fossil energy with socialist characteristics", so in the foreseeable future, diesel engines will mainly exist in the form of black smoke and will not be popularized. Considering the engine emission certification system with China characteristics, it is basically uneconomical and impossible for China people to spontaneously produce clean diesel engines. As for electric cars, I feel more like a joke at this stage. No one wants a car weighing 1.5T to be charged only once every 200km, not to mention that there is no power plug in my garage. If I choose, diesel-electric hybrid is the future. It seems that the public already knows about it. In addition, do you know that Audi powered by pure diesel has won the Le Mans Cup (now WEC World Endurance Championship) for several years in a row? This year, WEC Audi's diesel-electric hybrid car almost won the championship. More than 50% passenger cars in Europe are powered by diesel. European countries realize that diesel is actually an energy source no less than gasoline. In order to encourage the promotion of clean diesel engines, Europe, especially Germany, even subsidized diesel to offset the price disadvantage caused by the higher price of diesel engines than gasoline engines, and used it to promote clean diesel engines.