Aerosol Characterization during the Summer 2017 Huge Fire Event on Mount Vesuvius (Italy) by Remote Sensing and In Situ Observations

Antonella Boselli,Alessia Sannino,Salvatore Amoruso,Mariagrazia D’Emilio,Xuan Wang

doi:10.3390/rs13102001

Abstract

During the summer of 2017, multiple huge fires occurred on Mount Vesuvius (Italy), dispersing a large quantity of ash in the surrounding area ensuing the burning of tens of hectares of Mediterranean scrub. The fires affected a very large area of the Vesuvius National Park and the smoke was driven by winds towards the city of Naples, causing daily peak values of particulate matter (PM) concentrations at ground level higher than the limit of the EU air quality directive. The smoke plume spreading over the area of Naples in this period was characterized by active (lidar) and passive (sun photometer) remote sensing as well as near-surface (optical particle counter) observational techniques. The measurements allowed us to follow both the PM variation at ground level and the vertical profile of fresh biomass burning aerosol as well as to analyze the optical and microphysical properties. The results evidenced the presence of a layer of fine mode aerosol with large mean values of optical depth (AOD > 0.25) and Ångstrom exponent (γ > 1.5) above the observational site. Moreover, the lidar ratio and aerosol linear depolarization obtained from the lidar observations were about 40 sr and 4%, respectively, consistent with the presence of biomass burning aerosol in the atmosphere.

Highlights

Atmospheric aerosol content and composition are of particular interest, playing an important role in several areas, such as Earth’s radiative budget, air quality, human health, etc. [1,2,3]
The present work reports the results of a study carried out during a huge fire event that occurred on Mount Vesuvius (Italy) in July 2017
A synergetic approach, based on the simultaneous use of both in situ and passive and active remote sensing instruments, allows for monitoring and characterizing the optical and microphysical properties of the aerosol produced by the Vesuvius fire that was subsequently dispersed in the atmosphere across a short distance over the city of Naples, in the period from 10 to 17 of July 2017

Summary

Introduction

Atmospheric aerosol content and composition are of particular interest, playing an important role in several areas, such as Earth’s radiative budget, air quality, human health, etc. [1,2,3]. Biomass burning injects smoke particles into the atmosphere whose properties change with time according to combustion phase, mixing phenomena and atmospheric conditions. For this reason, biomass burning is considered one of the main aerosol emission sources. Biomass burning has been extensively studied, both at regional and global scales, with the aim of investigating the spatial and temporal variability of chemical, optical and microphysical properties of the particles injected into the atmosphere and the associated transport mechanisms [7,8,9,10,11,12].

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Results

Conclusion