Several epidemiological studies have shown a close relationship between the mass of particulate matter (PM) and its effects on human health. This study reports the identification of inorganic and organic components by attenuated total reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR) analysis in PM₁₀ and PM_2.5 filters collected from three air quality monitoring stations in the city of Palermo (Sicily, Italy) during non-Saharan dust events and Saharan events. It also provides information on the abundance and types of water-soluble species. ATR-FTIR analysis identified sulfate, ammonium, nitrate, and carbonate matter characterized by vibrational frequencies at 603, 615, 670, and 1100 cm^–1 (SO₄^2–); at 1414 cm^–1 (NH₄⁺); at 825 and 1356 cm^–1 (NO₃^–); and at 713, 730, and 877 cm^–1 (CO₃^2–) in PM₁₀ and PM_2.5 filters. Moreover, aliphatic hydrocarbons were identified in the collected spectra. Stretching frequencies at 2950 cm^–1 were assigned to CH₃ aliphatic carbon stretching absorptions, while frequencies at 2924 and 2850 cm^–1 indicated CH₂ bonds. In filters collected during Saharan dust events, the analysis also showed the presence of absorbance peaks typical of clay minerals. The measurement of soluble components confirmed the presence of a geogenic component (marine spray and local rocks) and secondary particles ((NH₄)₂SO₄, NH₄NO₃) in the PM filters. ATR-FTIR characterization of solid surfaces is a powerful analytical technique for identifying inorganic and organic compounds in samples of particulate matter.

At the end of 2019, the first cases of coronavirus disease (COVID-19) were reported in Wuhan, China. Thereafter, the number of infected people increased rapidly, and the outbreak turned into a national crisis, with infected individuals all over the country. The COVID-19 global pandemic produced extreme changes in human behavior that affected air quality. Human mobility and production activities decreased significantly, and many regions recorded significant reductions in air pollution. The goal of our investigation was to evaluate the impact of the COVID-19 lockdown on the concentrations of the main air pollutants in the urban area of Palermo (Italy). In this study, the trends in the average concentrations of CO, NO₂, O₃, and PM₁₀ in the air from 1 January 2020 to 31 July 2020 were compared with the corresponding average values detected at the same monitoring stations in Palermo during the previous five years (2015–2019). During the lockdown period (10 March–30 April), we observed a decrease in the concentrations of CO, NO₂, and particulate matter (PM)₁₀, calculated to be about 51%, 50%, and 45%, respectively. This confirms that air pollution in an urban area is predominantly linked to vehicular traffic.