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The Istituto Superiore di Sanità (ISS, the National Institute of Health of Italy) and the Istituto dei Motori (IM) of the Consiglio Nazionale delle Ricerche (CNR, National Research Council) have carried out this study, jointly funded by the two institutes together with the Ministry of Environment. The chemical and toxicological characteristics of emissions from two urban bus engines were studied: a diesel engine fueled with both diesel oil and biodiesel blend and an equivalent spark-ignition one fuelled with compressed natural gas, operating in steady-state conditions. Regulated and unregulated pollutants, such as carcinogenic polycyclic aromatic hydrocarbons and nitrated derivatives, carbonyl compounds and light aromatic hydrocarbons were quantified. Mutagenicity of the emissions was evaluated by the Salmonella typhimurium/mammalian microsome assay. The effect of the fuels under study on the size distribution of particulate matter was also evaluated. The impact of diesel-powered transport on urban air quality, and the potential benefits for human health deriving from the use of natural gas for public transport, are discussed.

Le emissioni autoveicolari contribuiscono in maniera significativa all’inquinamento urbano e rappresentano un serio rischio per la salute umana, tanto che la IARC (IARC, 1989) ha classificato le emissioni diesel nel gruppo 2A (probabile cancerogeno umano) e le emissioni da autoveicoli a benzina nel gruppo 2B (possibile cancerogeno umano). In particolare, i motori diesel sono tra le sorgenti principali di particelle fini nelle aree urbane. Queste particelle si depositano facilmente nel tratto respiratorio e possono fungere da iniziatori di tumori polmonari o provocare altre malattie dell’apparato respiratorio (USEPA, 2002; Health Effects Institute, 2002). Il articolato proveniente da emissioni autoveicolari è costituito da una matrice solida carboniosa sulla quale sono adsorbiti centinaia di composti tossici, molti dei quali presentano attività mutagena e/o cancerogena. Fra questi, particolare rilevanza tossicologica hanno gli idrocarburi policiclici aromatici (IPA) e i loro derivati nitrati (Nitro-IPA), la cui presenza nelle emissioni è stata correlata con il combustibile usato e con la tecnologia motoristica impiegata (Concawe, 1998; Westerholm, 1994). Poiché la maggior parte degli autobus destinati al trasporto pubblico urbano è dotata di motori diesel, l’emissione di particolato avviene in aree densamente popolate, contribuendo significativamente all’esposizione della popolazione generale. Specificamente esposte alle emissioni risultano anche le categorie dei lavoratori impiegati sulle strade a tutela della disciplina del traffico, come ad esempio gli agenti di polizia municipale e di polizia stradale.

Natural gas has a favorable effect on both the engine performance and emissions. The heavy-duty vehicles fueled with natural gas have very low emission levels, not easily obtainable with other fuels, and therefore they are considered the most practicable EEV (Enhanced Environmental Friendly Vehicles). Moreover, the assessment of fuel availability makes its use possible for a long time, whilst the new generation of feeding systems offers solutions to the problem of fuel composition variability. Nevertheless, the positive environmental aspects often are not totally known by people involved in natural gas application, therefore some limitations in the diffusion of this fuel in the transportation sector still appear. This paper refers about the activities, under development at the Istituto Motori, aimed to evaluate the toxicity of engine exhausts gas, based on the analysis of components harmful to human health, such as the carbonyl compounds, PAHs and particulate matter. A research program to determinate the toxicity of the emissions of bus engines when fueled with natural gas and with diesel oil, pure or mixed with fuel from vegetable oil, was jointly planned by the Istituto Motori and the Istituto Superiore di Sanit\ab (Italian National Institute of Health). The activity was co-funded by the two institutes together with the Italian Ministry of Environment. This study is now in progress, its design is illustrated and the first results are presented.

The study examined the proximate composition, cholesterol content and fatty acid profile of fillet from the most important species captured in Italian seas and commonly consumed in the European Union, such as anchovy (Engraulis encrasicholus L.), red mullet (Mullus barbatus L.), European hake (Merluccius merluccius L.) and Atlantic bonito (Sarda sarda L.). The fish were caught in three different geographic areas of the Italian seas: south Tyrrhenian (ST), south Adriatic (SA) and Ionian (IO). Anchovy from the ST sea had the highest lipid content (2.27%) compared to fish captured in the SA (1.81%) and IO seas (1.91%) (P < 0.01). Red mullet captured in the SA exhibited the highest amount of lipid content (7.54%) compared to fish from the ST (1.82%) and IO seas (3.23%) (P < 0.01). The total cholesterol content of fish did not show significant differences from one geographic area to the other, particularly for European hake (from 98 to 66 mg per 100 g). The fatty acid profile of anchovy species was not affected by the geographical capture area. European hake caught in the ST sea showed the highest proportion of DHA (29.13%) in comparison to those captured in the SA (19.98%) and IO seas (19.84%). Atlantic bonito from the ST had the highest proportions of DHA (24.94%), compared to those from the SA (12.08%) and IO seas (13.83%). The SA bonitos contained a significantly lower proportion of EPA (3.31%) in comparison to fish from both the ST and IO seas (5.66 and 5.17%, respectively). Red mullet captured in the ST exhibited the highest proportions of DHA, n-3 PUFA, and total PUFA, and significantly lower proportions of oleic acid and MUFA. The fish from the ST sea showed better nutritional traits than those from other geographical areas although they all had excellent nutritional traits due to the low fat content and very high n-3 PUFA proportion.