Despite years of research and measurement, we still know too little about the mechanisms that cause smog. Today’s air monitoring system fulfils its main tasks: it informs residents of exceedances in the permissible concentrations of particulate matter, provides data for statistical purposes, and the resulting findings have legal consequences. But it does not provide answers to the questions: why is smog still with us? Will we ever be able to get rid of it? Is smog really just a local problem for local authorities? What are the real limits to preventing smog? Specialised modern research instruments are needed to answer these questions. It is therefore necessary to strengthen cooperation between the research and development community and institutions responsible for air monitoring in order to expand existing measurement tools. Then the fight for clean air will be effective and successful.