Fast screening compositions of PM2.5 by ATR-FTIR: Comparison with results from IC andOC/EC analyzers

Year-long and seasonal differences of PM2.5 chemical characteristics and their role in the viability of human lung epithelial cells (A549)

Fine particulate matters-PM2.5 in the air can have considerable negative effects on human health and the environment. Various human cell-based studies examined the effect of PM2.5 on human health in different cities of the world using various chemical parameters. Unfortunately, limited information is available regarding the relationship between toxicity and chemical characteristics of PM2.5 collected in Istanbul, Türkiye, located in one of the most populated cities in the world. To investigate the chemical characteristics and cytotoxicity of PM2.5 in Istanbul, samples were collected for 12 months, then potentially toxic metals, oxidative potential, and particle indicators (e.g., functional groups and elements) were determined, and the cytotoxicity of PM2.5 on human A549 lung alveolar epithelial cells was examined. The mean PM2.5 mass concentration was 24.0 ± 17.4 µg m-3 and higher in cold months compared to other seasons. Moreover, the results of the metals, elemental, and functional groups indicated that seasonal and monthly characteristics were influenced by the regional anthropogenic sources and photochemistry input. The cytotoxicity results also showed that the viability of A549 cells was reduced with the exposure of PM2.5 (30-53%) and higher cytotoxicity was obtained in summer compared to the other seasons due to the impact of the metals, elements, and oxidative characteristics of PM2.5.

Recent Progress in Daytime Radiative Cooling: Advanced Material Designs and Applications

Passive daytime radiative cooling (PDRC) is emerging as a promising cooling technology. Owing to the high, broadband solar reflectivity and high mid-infrared emissivity, daytime radiative cooling materials can achieve passive net cooling power under direct sunlight. The zero-energy-consumption characteristic enables PDRC to reduce negative environmental issues compared with conventional cooling systems. In this review, the development of advanced daytime radiative cooling designs is summarized, recent progress is highlighted, and potential correlated applications, such as building cooling, photovoltaic cooling, and electricity generation, are introduced. The remaining challenges and opportunities of PDRCs are also indicated. It is expected that this review provides an overall picture of recent PDRC progress and inspires future research regarding the fundamental understanding and practical applications of PDRC.

ATR-FTIR Spectral Analysis and Soluble Components of PM10 And PM2.5 Particulate Matter over the Urban Area of Palermo (Italy) during Normal Days and Saharan Events

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.

Electrospray Film Deposition for Solvent-Elimination Infrared Spectroscopy

The application of electrospray (ES) for quantitative transfer of analytes from solution to an internal reflection element for analysis by attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy has been developed in this work. The ES ATR FT-IR method is evaluated with non-volatile and semi-volatile organic and inorganic compounds dissolved in pure organic solvents or organics in a mixture with water. The technique demonstrates the capability for rapid solvent evaporation from dilute solutions, facilitating the creation of thin films that allow ATR FT-IR to generate transmission-mode-like spectra. Electrospray ATR FT-IR with multiple reflections displays a linear response ( R² = 0.95-0.99) in absorbance with the deposited mass and instrumental detection limit < 100 ng, which demonstrates potential for quantitative applications. The method is applicable when crystalline substances are present, even though the formation of particles restricts the upper limit of mass loadings relative to substances forming homogeneous films. In addition to the solvent, semi-volatile compounds can evaporate during the ES process; the magnitude of losses will depend on solution composition and temperature.