Research expertise on Physicochemical aerosol characterization and nuclear analytical techniques for climatic active aerosol species, nano-particle metrology, development of novel sampling and measurement techniques for aerosol particles, exposure of humans to aerosol contaminants such as heavy metals and radioactive pollutants, and retrieval of emission source impact, source apportionment and receptor modelling. PI for Demokritos in several EU FP and DG-ENV programmes, IAEA Regional projects & other National programmes. Established infrastructure, including the Athens GAW/ACTRIS Demokritos station, the Mt. Helmos Free troposphere Aerosol and GHG station and the QA/QC aerosol lab facility (EN 17025 accredited). National Counterpart for Greece in Regional IAEA programmes. He has supervised 12 PhD theses and 14 MSc project theses. He has more than 145 articles in peer-reviewed journals. Invited reviewer and project evaluator (EURAMET European Metrology Research, the Czech & Hungarian Academy of Sciences Grant programmes). Invited IAEA expert missions (3) Africa and Middle East, Member of the National Emergency Action Plan “Xenokratis”. Founding member and president of the Hellenic Association for Aerosol Research.