Concurrent Influence of Different Natural Sources on the Particulate Matter in the Central Mediterranean Region during a Wildfire Season

Abstract

Wildfire occurrence and severity in the Mediterranean region during the summer season is increasing, being favoured by climate change-induced conditions (i.e., drought, heatwaves). Moreover, additional natural sources frequently impact this region, particularly Saharan dust intrusions. This study focuses on the combined effect of wildfires and Saharan dust on the air quality of the central Mediterranean Basin (CMB) during 2017, an exceptional year for forested burned areas in southern Italy. The annual behaviors of PM2.5, PM10, CO, benzene, and benzo(a)pirene measurements that were recorded at a rural regional-background station located in southern Italy, highlighted a concentration increase during summer. Both Saharan dust and wildfire events were identified while using Navy Aerosol Analysis and Prediction System (NAAPS) model maps, together with high-resolution Weather Research and Forecast—Hybrid Single-Particle Lagrangian Integrated Trajectory (WRF-HYSPLIT) back-trajectories. Additionally, Visible Infrared Imaging Radiometer Suite (VIIRS) satellite detections were considered to establish the enrichment of air masses by wildfire emissions. Finally, the occurrence of these natural sources, and their influence on particulate matter, were examined. In this case study, both PM2.5 and PM10 exceedances occurred predominantly in conjunction with wildfire events, while Saharan dust events mainly increased PM10 concentration when overlapping with wildfire effects.

Using Radiometric Measurements to Separate Dust and Smoke Radiative Effects during a Combined Smoke–Dust Event

“…months also result in frequent wildfires in mid-latitude Mediterranean countries, with implications for human health and climate (e.g., [7]). As discussed in recent studies [8,9], understanding the impact of dust and smoke mixing is essential to understand the Mediterranean climate.…”

“…It is estimated that on an annual basis, 3-10% of the global horizontal irradiance (GHI) is attenuated by dust aerosols over the Eastern Mediterranean [6]. The dry conditions during the summer months also result in frequent wildfires in mid-latitude Mediterranean countries, with implications 2 of 6 for human health and climate (e.g., [7]). As discussed in recent studies [8,9], understanding the impact of dust and smoke mixing is essential to understand the Mediterranean climate.…”

Compositional Spatio-Temporal PM2.5 Modelling in Wildfires

“…Wildfires are natural or human-based phenomena that emit various air pollutants into the atmosphere [1,2]. PM 2.5 is one of the most critical pollutants to human health produced by wildfires [3,4]. PM 2.5 , inhaled and transported by the bloodstream, can impair the lungs and other vital organs, and its impact is more harmful if the source is from wildfires [5,6].…”