Martin Pechout

Genotoxic potential of organic extracts from particle emissions of diesel and rapeseed oil powered engines

The present study was performed to identify possible genotoxicity induced by organic extracts from particulate matter in the exhaust of two typical diesel engines run on diesel fuel and neat heated fuel-grade rapeseed oil: a Cummins ISBe4 engine tested using the World Harmonized Steady State Test Cycle (WHSC) and modified Engine Steady Cycle (ESC) and a Zetor 1505 engine tested using the Non-Road Steady State Cycle (NRSC). In addition, biodiesel B-100 (neat methylester of rapeseed oil) was tested in the Cummins engine run on the modified ESC. Diluted exhaust was sampled with high-volume samplers on Teflon coated filters. Filters were extracted with dichlormethane (DCM) and DNA adduct levels induced by extractable organic matter (EOM) in an acellular assay of calf thymus DNA coupled with (32)P-postlabeling in the presence and absence of rat liver microsomal S9 fraction were employed. Simultaneously, the chemical analysis of 12 priority PAHs in EOM, including 7 carcinogenic PAHs (c-PAHs) was performed. The results suggest that diesel emissions contain substantially more total PAHs than rapeseed oil emissions (for the ESC) or that these concentrations were comparable (for the WHSC and NRSC), while c-PAHs levels were comparable (for the ESC) or significantly higher (for the WHSC and NRSC) for rapeseed oil emissions. DNA adduct levels induced by diesel and rapeseed oil derived EOM were comparable, but consistently slightly higher for diesel than for rapeseed oil. Highly significant correlations were found between 12 priority PAHs concentrations and DNA adduct levels (0.980; p<0.001) and these correlations were even stronger for c-PAHs (0.990; p<0.001). Metabolic activation by the microsomal S9 fraction resulted in several fold higher genotoxicity, suggesting a major contribution of PAHs to genotoxicity. Directly acting compounds, other than c-PAHs, and not requiring S9 to exhibit DNA reactivity were also significant. Generally, DNA adduct levels were more dependent on the type of engine and the test cycle than on the fuel. Our findings suggest that the genotoxicity of particulate emissions from the combustion of rapeseed oil is significant and is comparable to that from the combustion of diesel fuel. A more detailed study is ongoing to verify and extent these preliminary findings.

Assessment of a Low-Cost Portable Proportional Exhaust Sampling System for Gravimetric Particulate Matter Emissions Measurement

Shrnutí Částice obsažené ve výfukových plynech spalovacích motorů jsou jejich pro lidské zdraví nejvíce škodlivou složkou. Se snižující se celkovou hmotností emitovaných částic se zvyšují nároky na její měření, které vyžaduje plnoprůtočný ředicí tunnel nebo proporcionální vzorkovač s ředěním části toku s rychlou odezvou. Pro umožnění takových měření během jízdy vozidla a v méně vybavených laboratořích bylo vytvořeno nízkonákladové zařízení pro proporcionální vzorkování výfukových plynů. Zařízení využívá dvojici regulátorů hmotnostního průtoku, z nichž jeden dodává proměnlivé množství ředicího vzduchu do miniaturního ředicího tunelu, a druhý udržuje konstantní průtok směsi ředicího vzduchu a výfukových plynů přes filtr, na který jsou částice vzorkovány. Výsledky naměřené tímto systémem během dynamických jízdních cyklů jsou, po korekci systematického rozdílu, v rozmezí faktoru dvou od výsledků gravimetrické analýzy vzorků odebraných z klasického plnoprůtočného ředicího tunelu. ABSTRACT Particulate matter (PM) is considered to be the most harmful component of internal combustion engine exhaust to human health. At decreasing levels of total PM mass, its measurement is challenging, requiring either a full-flow dilution tunnel or a fast-response, variable dilution ratio sampler. To allow for such measurements on the road and in lesser equipped laboratories, a low-cost proportional sampling system has been developed. The system uses a pair of mass flow controllers, one of which meters filtered air into a heated miniature partial-flow dilution tunnel, and the other one regulates the flow of diluted exhaust through a filter on which PM is sampled. Results obtained with this system during transient tests fall, after corrections for measurement bias, within a factor of two of measurement obtained with a full-flow dilution tunnel.