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In the lower atmosphere, CO2 emissions impact human health and ecosystems, making data at this level essential for addressing carbon-cycle and public-health questions. The atmospheric concentration of CO2 is crucial in urban areas due to its connection with air quality, pollution, and climate change, becoming a pivotal parameter for environmental management and public safety. In volcanic zones, geogenic CO2 profoundly affects the environment, although hydrocarbon combustion is the primary driver of increased atmospheric CO2 and global warming. Distinguishing geogenic from anthropogenic emissions is challenging, especially through air CO2 concentration measurements alone. This study presents survey results on the stable isotope composition of carbon and oxygen in CO2 and airborne CO2 concentration in Naples' urban area, including the Campi Flegrei caldera, a widespread hydrothermal/volcanic zone in the metropolitan area. Over the past 50 years, two major volcanic unrests (1969–72 and 1982–84) were monitored using seismic, deformation, and geochemical data. Since 2005, this area has experienced ongoing unrest, involving the pressurization of the underlying hydrothermal system as a causal factor of the current uplift in the Pozzuoli area and the increased CO2 emissions in the atmosphere. To better understand CO2 emission dynamics and to quantify its volcanic origin a mobile laboratory was used. Results show that CO2 levels in Naples' urban area exceed background atmospheric levels, indicating an anthropogenic origin from fossil fuel combustion. Conversely, in Pozzuoli's urban area, the stable isotope composition reveals a volcanic origin of the airborne CO2. This study emphasizes the importance of monitoring stable isotopes of atmospheric CO2, especially in volcanic areas, contributing valuable insights for environmental and public health management. [ABSTRACT FROM AUTHOR]

The La Fossa volcano is near the inhabited zone of the island of Vulcano and is a suitable case for studying gas sources of different geological origins. Since the last eruption, fumarolic-solfataric activity has interested this area with fumarolic emissions, mainly at the top of the volcanic cone and at Vulcano Porto. In recent decades, the anomalous degassing zones on the island have not significantly changed their location. On the contrary, there have been several significant changes in the emission rate due to the addition of volcanic gas. In these zones, CO2 flux from the ground is responsible for a decrease in the indoor air quality. A recent increase in volcanic degassing led to an increase in the gas hazard in the inhabited area of Vulcano Island, and people were temporarily displaced from Vulcano Porto. The results of this study show that a monitoring system can be used for the early detection of transients in soil CO2 flux (φCO2) in the anomalous degassing zone of Vulcano. Synchronous monitoring of φCO2 and outdoor air CO2 concentration has shown variations in volcanic degassing that affect outdoor air CO2 concentration in the populated zone of Faraglione. [ABSTRACT FROM AUTHOR]

The fluorescence of porphyrins is altered by modulating the interactions between the anionic porphyrins and the protonated polylysine through the pH values. The tetraionic meso-tetrakis(4-sulfonatophenyl)porphine (H2TPPS) exists in monomeric form and its fluorescence is not pH-dependent. However, the addition of polylysine, self-aggregation in H2TPPS has been observed. Also, there is a modification in the intensity of the fluorescence versus the pH behavior showing a sigmoidal profile.

Air permeability is a major physical factor affecting the advective transport of a gas through the soil, and variations in this parameter can strongly influence the emission of endogenous gases from the soil to the atmosphere. In this paper, we illustrated a new and simple method for measuring in situ air permeability based on the measurement of air pressure inside a special probe inserted into the soil. The method was designed and developed primarily to study the relationship between air permeability and the soil CO2 flux in an active volcanic area. The method was used for continuous monitoring of the air permeability at two different locations on the island of Vulcano. At the same time, the values of the atmospheric pressure, temperature, rain, and volumetric water content of the soil were also acquired to investigate their effect on soil air permeability and soil CO2 flux. The results showed that during the monitoring period, soil air permeability exhibited minor variations at each site, while larger variations in the soil CO2 flux were recorded. The effect of soil air permeability on soil CO2 flux was negligible at both sites, whereas a strong dependence of soil CO2 flux on volumetric water content and on atmospheric pressure was found. Furthermore, the variation in air permeability recorded at both sites was much lower than that predicted using some well-known predictive models, showing that the relationship among different soil transport parameters is more complex in real field conditions than would be expected by semiempirical models. [ABSTRACT FROM AUTHOR]

Chiral ternary complexes of the protonated form of tetra-anionic meso-tetrakis(4-sulfonatophenyl)porphine apparently have a 'life' independent from the template but retain 'memory' of the shape of the mold used for their formation. This was gleaned from spectroscopic data derived from a study of these aggregates in water solution, on a preformed complex between alpha-helical polyglutamate and the copper(II) derivative of the tetracationic meso-tetrakis(N-methylpyridinium-4-yl)porphine. These species seem to memorize and retain the chiral information imprinted by the template, despite the 'disruption' by pH-induced conformational transitions of the matrix chirality.

Evidences on the formation of chiral ternary heteroaggregates in which cationic porphyrins act as spacers between an anionic chiral polymeric matrix and anionic porphyrins were presented. The copper, gold, manganese and zinc derivatives of meso-tetrakis(N-methylpyridinium-4-yl)porphine were used as cationic porphyrins. These porphyrins stimulated the formation of H- and J-type aggregates and acted as spacers by shielding the electrostatic repulsion between the anionic matrix and the negative sulfonic groups. This allowed a long distance interaction of the matrix with the aggregates.