BackgroundShip engine emissions are important with regard to lung and cardiovascular diseases especially in coastal regions worldwide. Known cellular responses to combustion particles include oxidative stress and inflammatory signalling.ObjectivesTo provide a molecular link between the chemical and physical characteristics of ship emission particles and the cellular responses they elicit and to identify potentially harmful fractions in shipping emission aerosols.MethodsThrough an air-liquid interface exposure system, we exposed human lung cells under realistic in vitro conditions to exhaust fumes from a ship engine running on either common heavy fuel oil (HFO) or cleaner-burning diesel fuel (DF). Advanced chemical analyses of the exhaust aerosols were combined with transcriptional, proteomic and metabolomic profiling including isotope labelling methods to characterise the lung cell responses.ResultsThe HFO emissions contained high concentrations of toxic compounds such as metals and polycyclic aromatic hydrocarbon, and were higher in particle mass. These compounds were lower in DF emissions, which in turn had higher concentrations of elemental carbon (“soot”). Common cellular reactions included cellular stress responses and endocytosis. Reactions to HFO emissions were dominated by oxidative stress and inflammatory responses, whereas DF emissions induced generally a broader biological response than HFO emissions and affected essential cellular pathways such as energy metabolism, protein synthesis, and chromatin modification.ConclusionsDespite a lower content of known toxic compounds, combustion particles from the clean shipping fuel DF influenced several essential pathways of lung cell metabolism more strongly than particles from the unrefined fuel HFO. This might be attributable to a higher soot content in DF. Thus the role of diesel soot, which is a known carcinogen in acute air pollution-induced health effects should be further investigated. For the use of HFO and DF we recommend a reduction of carbonaceous soot in the ship emissions by implementation of filtration devices.

Gaseous and particulate emissions from a ship diesel research engine were elaborately analysed by a large assembly of measurement techniques. Applied methods comprised of offline and online approaches, yielding averaged chemical and physical data as well as time-resolved trends of combustion by-products. The engine was driven by two different fuels, a commonly used heavy fuel oil (HFO) and a standardised diesel fuel (DF). It was operated in a standardised cycle with a duration of 2 h. Chemical characterisation of organic species and elements revealed higher concentrations as well as a larger number of detected compounds for HFO operation for both gas phase and particulate matter. A noteworthy exception was the concentration of elemental carbon, which was higher in DF exhaust aerosol. This may prove crucial for the assessment and interpretation of biological response and impact via the exposure of human lung cell cultures, which was carried out in parallel to this study. Offline and online data hinted at the fact that most organic species in the aerosol are transferred from the fuel as unburned material. This is especially distinctive at low power operation of HFO, where low volatility structures are converted to the particulate phase. The results of this study give rise to the conclusion that a mere switching to sulphur-free fuel is not sufficient as remediation measure to reduce health and environmental effects of ship emissions.

Gas-phase emission samples of carbonyl compounds (CCs) were collected from two modern wood combustion appliances. Multiple repetitions were conducted on masonry heater operated with three logwood species (birch, beech, and spruce) and for a pellet boiler operated by softwood pellet with normal combustion and unoptimized combustion (in which the secondary combustion air flow rate was decreased). The sampling of CCs was performed from diluted exhaust using 2,4-dinitrophenylhydrazine (DNPH) cartridges. The CCs-hydrazone derivatives were analyzed by a gas chromatography−selective ion monitoring−mass spectrometry (GC-SIM-MS) method. Twelve (12) CCs were quantified in the masonry heater emissions and 8 in the pellet boiler emissions. The total carbonyl emission factors (EFs) for logwood were determined to be as follows: birch, 113 ± 18 mg kg −1 ; beech, 178 ± 31 mg kg −1 ; spruce, 171 ± 19 mg kg −1 ; and, for softwood pellet with normal combustion, 6 ± 0.9 mg kg −1 and for softwood pellet with unoptimized combustion, 6.5 ± 1 mg kg −1 . In masonry heater operation, birch exhibits the lowest emission factors, compared to other wood types. No significant differences were noticed between the emission of normal and unoptimized combustion for the pellet boiler operation. The emission profile examination showed that formaldehyde and acetaldehyde were the predominated carbonyls in the emission, regardless of the wood type. Time-resolved results obtained via single-photon ionization time-of-flight mass spectrometry (SPI-TOFMS) depict that, in masonry heater emissions, most carbonyls are produced as a new batch of wood is introduced.

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