NOx, carbon particulate, methane and VOC are among the most noxious emissions that contribute to deteriorate air quality and, along with CO₂, they are slowly impacting on climate change. They come from all sector and activities that include energy, transport, buildings, industry, waste management, agriculture, forestry, and other forms of land management. The treatment of exhaust emissions represents one of the tools that we have to reduce the impact of human activities on the environment. Catalysis has a leading role among the several techniques chemical engineers offer to cope with emissions. Our group, in cooperation with several leading companies, has been involved in the design of robust catalytic formulations for reduction of methane, carbon soot, VOC and NOx emissions from mobile and stationary sources. These studies cover the entire stage of catalyst development from the synthesis protocol to the scale up, characterization and testing under representative conditions. These allows to include the analysis of fundamental issues that control the behavior of the catalysts at the nano scale to the details of final applications that require a fine tuning of engineering issues at a larger scale.