Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 2067-2084, 2017
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
10 Feb 2017
Constraining the ship contribution to the aerosol of the central Mediterranean
Silvia Becagli1, Fabrizio Anello2, Carlo Bommarito2, Federico Cassola3,4, Giulia Calzolai5, Tatiana Di Iorio6, Alcide di Sarra6, José-Luis Gómez-Amo6,7, Franco Lucarelli5, Miriam Marconi1, Daniela Meloni6, Francesco Monteleone2, Silvia Nava5, Giandomenico Pace6, Mirko Severi1, Damiano Massimiliano Sferlazzo8, Rita Traversi1, and Roberto Udisti1,9 1Department of Chemistry, University of Florence, Sesto Fiorentino, 50019 Florence, Italy
2ENEA, Laboratory for Observations and Analyses of Earth and Climate, 90141 Palermo, Italy
3Department of Physics & INFN, University of Genoa, 16146 Genoa, Italy
4ARPAL-Unità Operativa CFMI-PC, 16129 Genova, Italy
5Department of Physics, University of Florence & INFN-Firenze, Sesto Fiorentino, 50019 Florence, Italy
6ENEA, Laboratory for Observations and Analyses of Earth and Climate, 00123 Rome, Italy
7Department of Earth Physics and Thermodynamics, University of Valencia, Valencia, Spain
8ENEA, Laboratory for Observations and Analyses of Earth and Climate, 92010 Lampedusa, Italy
9ISAC CNR, Via Gobetti 101, 40129, Bologna, Italy
Abstract. Particulate matter with aerodynamic diameters lower than 10 µm, (PM10) aerosol samples were collected during summer 2013 within the framework of the Chemistry and Aerosol Mediterranean Experiment (ChArMEx) at two sites located north (Capo Granitola) and south (Lampedusa Island), respectively, of the main Mediterranean shipping route in the Straight of Sicily.

The PM10 samples were collected with 12 h time resolutions at both sites. Selected metals, main anions, cations and elemental and organic carbon were determined.

The evolution of soluble V and Ni concentrations (typical markers of heavy fuel oil combustion) was related to meteorology and ship traffic intensity in the Straight of Sicily, using a high-resolution regional model for calculation of back trajectories. Elevated concentration of V and Ni at Capo Granitola and Lampedusa are found to correspond with air masses from the Straight of Sicily and coincidences between trajectories and positions of large ships; the vertical structure of the planetary boundary layer also appears to play a role, with high V values associated with strong inversions and a stable boundary layer. The V concentration was generally lower at Lampedusa than at Capo Granitola V, where it reached a peak value of 40 ng m−3.

Concentrations of rare earth elements (REEs), La and Ce in particular, were used to identify possible contributions from refineries, whose emissions are also characterized by elevated V and Ni amounts; refinery emissions are expected to display high La ∕ Ce and La ∕ V ratios due to the use of La in the fluid catalytic converter systems. In general, low La ∕ Ce and La ∕ V ratios were observed in the PM samples. The combination of the analyses based on chemical markers, air mass trajectories and ship routes allows us to unambiguously identify the large role of the ship source in the Straight of Sicily.

Based on the sampled aerosols, ratios of the main aerosol species arising from ship emission with respect to V were estimated with the aim of deriving a lower limit for the total ship contribution to PM10. The estimated minimum ship emission contributions to PM10 were 2.0 µg m−3 at Lampedusa and 3.0 µg m−3 at Capo Granitola, corresponding with 11 and 8.6 % of PM10, respectively.

Citation: Becagli, S., Anello, F., Bommarito, C., Cassola, F., Calzolai, G., Di Iorio, T., di Sarra, A., Gómez-Amo, J.-L., Lucarelli, F., Marconi, M., Meloni, D., Monteleone, F., Nava, S., Pace, G., Severi, M., Sferlazzo, D. M., Traversi, R., and Udisti, R.: Constraining the ship contribution to the aerosol of the central Mediterranean, Atmos. Chem. Phys., 17, 2067-2084, doi:10.5194/acp-17-2067-2017, 2017.
Publications Copernicus
Short summary
The paper aims to implement a specific strategy to target the aerosol due to ship emissions. PM10 is collected south and north of the main shipping route through the Mediterranean. Other than ions and metals the analysis is complemented with measurements of rare earth elements, trajectories from a high resolution regional model and actual observations of ship traffic. The combination of these approaches allows for unambiguous identification of the ship contribution (8–11 % of PM10) in this area.
The paper aims to implement a specific strategy to target the aerosol due to ship emissions....