Constraining the ship contribution to the aerosol of the central Mediterranean

Abstract

Abstract. Particulate matter with aerodynamic diameters lower than 10 µm, (PM 10 ) 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 PM 10 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 PM 10 . The estimated minimum ship emission contributions to PM 10 were 2.0 µg m −3 at Lampedusa and 3.0 µg m −3 at Capo Granitola, corresponding with 11 and 8.6 % of PM 10 , respectively.

Chemical Composition of Aerosol over the Arctic Ocean from Summer ARctic EXpedition (AREX) 2011–2012 Cruises: Ions, Amines, Elemental Carbon, Organic Matter, Polycyclic Aromatic Hydrocarbons, n-Alkanes, Metals, and Rare Earth Elements

“…They all correlate quite well with Al (linear correlation coefficients ranging between 0.55 and 0.80) showing that mineral dust is also a major source contribution for these elements. Nevertheless, as shown in previous works [132], they also arose from anthropic activities, such as ship emissions, since they are also present in heavy oil used as fuel for ships. On the basis of Moreno et al [74], particular La/Ce and La/V ratios can be used to identify the samples characterized by a significant contribution from ship emissions; by taking into account these ratios (La/Ce between 0.6 and 0.8 and La/V lower than 0.1), about the 30% of the samples here analyzed can be related to a relevant contribution of ship emissions.…”

Aerosol sources in the western Mediterranean during summertime: a model-based approach

“…Aksoyoglu et al (2016) showed that ship emissions in the Mediterranean may contribute up to 60 % of sulfate concentrations, as SO 2 is a major pollutant emitted from maritime transport. However, in comparison to on-road vehicles, ship emissions are still poorly characterized (Berg et al, 2012). Furthermore, the multiplicity of Mediterranean pollution sources and their interactions makes it difficult to quantify ship contributions to aerosol concentrations.…”

Air quality in the middle and lower reaches of the Yangtze River channel: a cruise campaign

“…There is a good correlation (R 2 > 0.99 and R 2 > 0.98, P < 0.01) between cation and anions (equivalent concentration) in PM 1.0 and PM 2.5 , respectively, implying a high quality of data and the same source of major ions in this cruise (Fig. S5a) (Boreddy and Kawamura, 2015). Additionally, the relationship between NH + 4 and Ca 2+ vs.…”