Volume 17, No. 1, January 2017, Pages 69-83 PDF(7.01 MB)
Effects of Polluted Air-Masses Advection on Atmospheric Particles in a Semi-Rural Site in South Italy by SEM-EDX Analysis
Antonio Lettino1, Mariarosaria Calvello1, Francesco Esposito2, Saverio Fiore1, Marina Lorusso1, Giulia Pavese1
1 Consiglio Nazionale delle Ricerche- Istituto di Metodologie per l’Analisi Ambientale (CNR-IMAA), 85050 Potenza, Italy
2 Università della Basilicata - Scuola di Ingegneria, C.da Macchia Romana, 85100 Potenza, Italy
- The impact of transported polluted aerosol at a semi-rural site was studied by SEM.
- Extensive modifications of both aerosol size and chemical properties were assessed.
- Enhanced availability of some elements to be found in a soluble phase.
- S-reacted particles represent a signature of anthropogenic activities.
- Polluted air mass advection can worsen both air quality and health effects.
The variation of aerosol properties under polluted air masses advection was studied in a semi-rural site in South Italy, by means of SEM-EDX analysis performed on particles collected on 13-stages impactor filters. Radiometric measurements, HYSPLIT back-trajectories and NAAPS maps helped to choose four measurement days of polluted air mass circulation, two of them collected in the warm season (31 July 2008, 16 September 2010) and two in the cold one (16 April 2009, 18 March 2010). Polluted aerosol characteristics were compared to those under background (BG) conditions (8 February 2011), highlighting differences in the particles chemical and morphological properties. One of the signatures of the air mass transport in the coarse fraction was the higher content of particles containing S, i.e., S-reacted, (27.5% on average) in comparison with BG conditions (1%). Two main sources of transported aerosols were identified: industrial processes and biomass burning, with fly ash, metal and S-rich particles in the first case, and K-salts and nitrate-coated Ca-bearing-particles in the second. Single particle analysis on the coarse fraction allowed large agglomerates of soot to be identified, with inclusions of silicate particles rich in Cu and Zn, Ca-S, fly ash and metals particles that are a clear indication of extensive modifications of aerosol size, chemical composition and, likely, radiative properties. In finer stages (EAD ≤ 0.94 µm) concurrent collection of organic and inorganic particles originated an agglomerate state matter mainly characterized by K and S for polluted conditions and by K only for BG.
Atmospheric aerosol; Long-range transport; Air pollution.