**About the Editors**

#### **Elena Hristova**

Elena Hristova is an associate professor at the National Institute of Meteorology and Hydrology, Bulgaria. She holds a PhD in Chemical Engineering (University of Chemical Technology and Metallurgy, Sofia, Bulgaria, 2012). Her research interests are in the field of chemical composition of atmospheric aerosols, the identification of major source groups of PM pollution in urban environments with receptor model, the measurement of Black carbon concentrations in ambient air, and the chemical composition of atmospheric deposition in Bulgaria. She has led and participated in a number of scientific and applied research projects and tasks at NIMH, from different national and international funding programs (International Atomic Energy Agency, Transboundary Cooperation with Turkey, European Regional Development Fund through the Innovative Actions for Urban Development initiative, and Bulgarian National Science Found).

#### **Manousos Ioannis Manousakas**

Manousos-Ioannis Manousakas received a Ph.D. in Environmental Monitoring and Analysis in 2014 at the Chemistry Department of the University of Patras, Greece. After his studies, he has worked as Collaborating Researcher in NCSR Demokritos and the Institute of Chemical Engineering Sciences in Greece, and at Paul Scherrer Institute in Switzerland. His key research interests include atmospheric pollution, and specifically particulate-related pollution, chemical analysis, and source apportionment. He has a strong international network of collaborators, shown by his published research papers in Scientific Journals, and participated in several Scientific Projects from different funding programs. He serves as a source apportionment expert in many projects worldwide organized by the International Atomic Energy Agency (IAEA). He is a reviewer board member at five journals, while until 2021 has served as Guest Editor in three journals.

#### **Anik ´o Angyal**

Aniko Angyal received her Ph.D. in Environmental Sciences in 2016 at P ´ al Juh ´ asz-Nagy Doctoral ´ School of the University of Debrecen, Hungary. After finishing her studies, she work as a Research Associate in Institute for Nuclear Research in Debrecen, Hungary. Her main research interests include atmospheric pollution, in particular chemical analysis and source identification. Another important scientific field is cultural heritage, where the main focus is the analysis of artefacts using ion beam analysis. She has been involved in several national and international scientific projects under various funding programs. She has been Guest Editor of three journals.

#### **Maria Gini**

Maria Gini is a collaborating researcher at the Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, NCSR "Demokritos" (NCSRD). She holds a PhD in Environmental Physics (National and Kapodistrian University of Athens, Greece, Physics Department, 2015). Her research focuses on aerosol microphysical, optical and chemical characterization with respect to air quality and climate change, aerosol-based nanotechnology and nano-particle metrology, GHGs, environmental radioactivity, and population exposure to aerosol contaminants. She has actively participated in several European and National projects (i.e. Research and Innovation, Metrology, Climate Change Adaptation).
