Aerosol transmission constitutes one of the major transmission routes of the SARS-CoV-2 pathogen. Due to the pathogen’s properties, research on its airborne transmission has some limitations. This paper focuses on silica nanoparticles (SiO₂) of 40 and 200 nm sizes as the physicochemical markers of a single SARS-CoV-2 particle enabling experiments on the transmission of bioaerosols in public spaces. Mixtures of a determined silica concentration were sprayed on as an aerosol, whose particles, sedimented on dedicated matrices, were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Since it was not possible to quantitatively identify the markers based on the obtained images, the filters exposed with the AirSampler aspirator were analyzed based on inductively coupled plasma optical emission spectroscopy (ICP-OES). The ICP-OES method enabled us to determine the concentration of silica after extracting the marker from the filter, and consequently to estimate the number of markers. The developed procedure opens up the possibility of the quantitative estimation of the spread of the coronavirus, for example in studies on the aerosol transmission of the pathogen in an open environment where biological markers—surrogates included—cannot be used.

The main aim of this work was to study the chemical composition of eighteen ground coffees from different countries and continents with regard to the content of hazardous substances as radioactive elements (⁴⁰K, ²²⁶Ra, ²²⁸Ra, ²³⁴U, ²³⁸U and ¹³⁷Cs), metals, including heavy metals, aluminum and some microelements (V, Cr, Mn, Fe, Co, Ni, Cu, Zn) as well as substances that have a positive effect on human health and well-being (polyphenols, proteins, fats and caffeine). The tests were carried out before and after the brewing process using the following techniques: gamma and beta spectrometry, a microwave-induced plasma optical emission spectrometer (MIP-OES), gravimetric method, UV–Vis spectrophotometry as well as thin-layer chromatography. The leaching percentage of certain elements/compounds in coffee infusions was also measured. The research showed clear differences between Arabica and Robusta coffees, and also allowed for identifying some differences between Arabica coffees depending on the place of their origin. The results presented can raise consumer awareness and help them make better food choices.