Search

Incomplete combustion processes in diesel engines produce particulate matter (PM) that significantly contributes to air pollution. Currently, there remains a knowledge gap in relation to the physical and chemical characteristics and also the biological reactivity of the PM emitted from old- and new-generation diesel vehicles. In this study, the emissions from a Euro 3 diesel vehicle were compared to those from a Euro 6 car during the regeneration of a diesel particulate filter (DPF). Different driving cycles were used to collect two types of diesel exhaust particles (DEPs). The particle size distribution was monitored using an engine exhaust particle sizer spectrometer and an electrical low-pressure impactor. Although the Euro 6 vehicle emitted particulates only during DPF regeneration that primarily occurs for a few minutes at high speeds, such emissions are characterized by a higher number of ultrafine particles (

Diesel exhaust particles (DEP) are responsible for both respiratory and cardiovascular effects. However many questions are still unravelled and the mechanisms behind the health effects induced by the exposure to ultrafine particles (UFP) need further investigations. Furthermore, different emission sources can lead to diverse biological responses. In this perspective, here we have compared the effects of three DEPs, two standard reference materials (SRM 1650b and 2975) and one DEP directly sampled from a EuroIV vehicle without Diesel Particulate Filter (DPF). For the biological investigations, different in vitro lung models involving both epithelial and vascular endothelial cells, were used. Cell viability, oxidative stress, inflammation, DNA damage and endothelial activation markers were investigated at sub-cytotoxic DEP doses. The data obtained have shown that only DEP EuroIV, which had the major content of polycyclic aromatic hydrocarbons (PAHs) and metals, was able to induce oxidative stress, inflammation and consequent endothelial activation, as demonstrated by the expression of adhesion molecules (ICAM-1 and VCAM-1) and the release of inflammatory markers (IL-8) from endothelial cells. Standard reference materials were not effective under our experimental conditions. These data suggest that oxidative stress, endothelial activation and systemic inflammatory cytokines release are crucial events after DEP exposure and that the source of DEP emission, responsible of the particle chemical fingerprint, may have a key role in the resulting adverse biological outcomes.

The determination of Mn, Fe, Co, and Zn was performed in gasoline, jet, and diesel fuel samples by electrothermal atomic absorption spectrometry using the Transverse Heated Filter Atomizer (THFA). Thermal conditions were experimentally defined for the investigated elements. The elements were analyzed without the addition of chemical modifiers, using organometallic standards for the calibration. Gasoline samples were analyzed directly, while jet and diesel fuel samples were diluted 1+3 with n-heptane. The following LODs were obtained using 40 µL injections: 0.08 µg/L Mn, 0.35 µg/L Fe, 0.54 µg/L Co, and 0.06 µg/L Zn. The limits of determination, calculated for diesel and jet fuel samples, were 1.2 µg/kg Mn, 4.9 µg/kg Fe, 7.6 µg/kg Co, and 0.8 µg/kg Zn. The corresponding limits of quantitation for gasoline samples were about four times higher. KEYWORDS: electrothermal atomic absorption, transverse heated filter atomizer, gasoline, diesel fuel, trace elements Introduction Electrothermal atomic absorption represents a suitable instrumental technique for the analysis of elements in petroleum products [1–5]. The technique shows very low detection limits, similar to or even better than those found for other spectroscopic techniques, such as Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) [6] and ICP-Mass Spectrometry (ICP-MS) [7–12]. Some problems were evidenced in the use of ETAAS when elements like Ni [3] and Pb [13] are analyzed, due to the different behavior of organo-metallic species during the thermal treatment of standards and samples. Recently, the use of transverse heated filter furnace for the analysis of trace elements in automotive fuels was proposed [14]. This instrumental technique showed interesting results for volatile elements, such as Cd and Pb. The filter furnace approach was the subject of several papers and of continuous developments in order to improve the design [15], to extend the range to low volatile elements [16], to employ the furnace in transverse heated atomizers [17], and to determine trace elements in aqueous and organic solutions [18,19]. The most interesting aspects of the filter furnace concept are: the capability to inject large volumes due to the large volume of the zone allocated to the sampling, the limited non-specific absorption by molecular species due to the filtering action of the furnace, and no need for chemical modifiers due to the furnace design.