Hourly Elemental Composition and Source Identification by Positive Matrix Factorization (PMF) of Fine and Coarse Particulate Matter in the High Polluted Industrial Area of Taranto (Italy)

Abstract

In the framework of an extensive environmental investigation, promoted by the Italian Health Ministry, the ISPESL (Istituto Superiore per la Prevenzione e la Sicurezza del Lavoro) and the CNR (Consiglio Nazionale della Ricerca), aerosol samples were collected in Taranto (one of the most industrialized towns in southern Italy) with high time resolution and analyzed by PIXE. The samples were collected in two periods (February–March and June 2004) and in two different sites: an urban district close to the industrial area and a small town 7 km N-NW of Taranto. The use of ‘‘streaker’’ samplers (by PIXE International Corporation) allowed for the simultaneous collection of the fine (<2.5 μm) and coarse (2.5–10 μm) fractions of particulate matter. PIXE analyses were performed with a 3 MeV proton beam from the 3 MV Tandetron accelerator of the INFN-LABEC laboratory. Particulate emissions as well as their atmospheric transport and dilution processes change within a few hours, but most of the results in literature are limited to daily time resolution of the input samples that are not suitable for tracking these rapid changes. Furthermore, since source apportionment receptor models need a series of samples containing material from the same set of sources in different proportions, a higher variability between samples can be obtained by increasing the temporal resolution rather than with samples integrated over a longer time. In this study, the high time resolution of the adopted approach allowed us to follow in detail the changes in the aerosol elemental composition due to both the time evolution of the industrial emissions and the time changes in meteorological conditions, and thus, transport pathways. Moreover, the location of the sampling sites, along the prevalent wind direction and in opposite positions with respect to the industrial site, allowed us to follow the impact of the industrial plume as a function of wind direction. Positive matrix factorization (PMF) analysis on the elemental hourly concentrations identified eight sources in the fine fraction and six sources in the coarse one.

LABEC, the INFN ion beam laboratory of nuclear techniques for environment and cultural heritage

“…The presence of other anthropogenic and natural sources was also identified. The source polar plots were able to identify the directional locations of different sources identified by PMF [ 79 ].

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“…The presence of other anthropogenic and natural sources was also identified. The source polar plots were able to identify the directional locations of different sources identified by PMF [79]. Another possibility is the study of pyrotechnic events, such as on New Year's Eve, national festivities and light festivals, which give rise to large (up to hundreds of μg/m 3 ), but transitory (up to hours) increases of urban atmospheric particulate matter mean levels, especially metalliferous particles (K, Mg, Ba, Cu, Sr, Al, Pb) which can be dangerous for the human health.…”

Measurement report: Receptor modelling for source identification of urban fine and coarse particulate matter using hourly elemental composition

“…In this study, concentrations of PM mass and its macro components, i.e., organic carbon, elemental carbon, secondary inorganic aerosols and other water-soluble inorganic ions, were not available with the hourly temporal resolution. Therefore, the obtained results can be used for a detailed source identification but source time series will be expressed in arbitrary units (see e.g., Lucarelli et al, 2020).…”

“…Identification of PM sources based on aerosol samples in 1-hour resolution has been carried out in Southern Europe, e.g. : at 4 urban sites in Barcelona (Spain), Porto (Portugal), Athens (Greece) and Florence (Italy) (Lucarelli et al, 2015); at an urban site in Elche (Spain) (Nicolás et al, 2020), at 6 sites of different types in Tuscany (Central Italy) (Nava et al, 2015) and in an industrial area of Taranto (Italy) (Lucarelli et al, 2020). Outside this region, hourly-resolved PM samples have been investigated e.g.…”

Atmospheric aerosols analysis and identification of polluting sources in the industrial city of Arak, Iran

“…In the elemental analysis of particulate matter, PIXE provides a rapid multi‐elemental analysis (only 5–10 min) capable to detect a large number of elements from Na, including important anthropogenic elements (S, V, Ni, Cu, Zn, As, and Pb), and the crustal elements (Al, Si, K, Ca, Ti, Mn, and Fe). Its high throughput is useful when a large number of samples have to be analyzed, which is essential in particulate matter studies [26] . Proton and alpha ions in the energy range 1–3 MeV are the most frequently used ions because of the higher X‐ray production cross‐section.…”