Air Quality Assessment in the Central Mediterranean Sea (Tyrrhenian Sea): Anthropic Impact and Miscellaneous Natural Sources, including Volcanic Contribution, on the Budget of Volatile Organic Compounds (VOCs)

Francesca Vichi,Massimiliano Frattoni,Giulio Esposito,Maria Concetta Tomasi Scianò,Mattia Perilli,Andrea Imperiali,Antonietta Ianniello,Angelo Cecinato

doi:10.3390/atmos12121609

Francesca Vichi, Massimiliano Frattoni + Show 6 more

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https://doi.org/10.3390/atmos12121609

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Abstract

The results of air pollution assessment during a 2017 cruise of the research ship “Minerva Uno” in the Tyrrhenian Sea are reported. Volatile Organic Compounds (VOCs), Oxygenated Volatile Organic Compounds (OVOCs), and pollutants such as nitrogen oxides, ozone, and sulphur dioxide were monitored throughout the cruise. The shallow waters at ten sites of the investigated area were also analyzed. Organic compounds such as n-alkanes showed a bimodal distribution with a maximum at C5–C6 and C10–C11 at sites the most affected by anthropic impact, whereas remote sites showed a unimodal distribution with maximum at C10–C11. The most abundant atmospheric OVOC was acetone (3.66 μg/m3), accounting for 38%; formaldehyde (1.23 μg/m3) and acetaldehyde (0.99 μg/m3) made up about 22–29% of the total. The influence of some natural sources as volcanoes, in the southern part of the Tyrrhenian Sea near the Aeolian arc was studied. This source did not induce any noticeable effect on the total amount of hydrocarbons nor on the levels of trace gases such as CFCs, whereas the trends of sulphur dioxide seemed to confirm a possible contribution. The impact of underwater emissions was observed near the Panarea and Vulcano islands, where lower pHs, high levels of Fe and Mn, and diagnostic of vent activity, were measured.

Highlights

Many anthropic and natural contributions, which presently have not been fully unfolded, constitute the blend of possible sources affecting the air quality in the Mediterranean Basin, due to local emissions and to long-range transport of pollution from other continents [1]
Formaldehyde concentrations found at the Antarctica were by far greater than the levels we found in the Mediterranean area
This study confirms the influence of some natural sources, such as volcanoes, in the strongly anthropized Mediterranean Sea in the southwestern area around the Aeolian arc, and shows that the main atmospheric pollutant emitted is sulphur dioxide

Summary

Introduction

Many anthropic and natural contributions, which presently have not been fully unfolded, constitute the blend of possible sources affecting the air quality in the Mediterranean Basin, due to local emissions and to long-range transport of pollution from other continents [1]. Emissions coming from several natural sources, such as vegetation, wildfires, and volcanic activity, should be accounted for, and especially the last source since it can significantly impact the southeastern part of the Tyrrhenian Sea. In addition, the effect of these sources can be further intensified by peculiar climatic conditions favoring photochemical pollution, in hot periods when the precipitation is scarce and the ventilation, mainly due to mild breezes, is poor [3]. The effect of these sources can be further intensified by peculiar climatic conditions favoring photochemical pollution, in hot periods when the precipitation is scarce and the ventilation, mainly due to mild breezes, is poor [3] All these factors make this area a climate change “hot spot” [4]

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