On 27.05.2021 Boyan Bonchev gave a presentation on the topic “A study of nano-magnetic iron-containing particles in the air above Sofia using Mössbauer spectroscopy”.
A semi-quantitative testing of dust samples from different locations around Sofia was presented using Mössbauer spectroscopy as a supporting method as well – scanning electronic microscopy with option for x-ray fluorescent analysis and identification of the chemical composition of the objects.