The interest in environmental pollution has grown in the last half century from a small number of people, who dealt sporadically and casually with pollution to the entire population of the globe and to the most diverse institutions and organizations. Of course, pollution deserves interest, primarily for its current aspects, because it creates inconveniences and damages that affect health, sometimes involving large masses of people. This forces its knowledge to be as thorough, urgent and extensive as possible. Diesel engine emissions, due to the nature of combustion, consist of a number of pollutants, the most dangerous of which are nitrogen oxides and suspended dust. The Euro VI emissions regulation, which will apply to all new commercial vehicles and buses produced after January 1, 2014, introduces significant reductions in tailpipe emissions. Thus, emissions of nitrogen oxides must be at least 80% lower, and those of particles reduced by 66% compared to the Euro V standard. Euro VI also introduces a limit on ammonia emissions for the first time.