Michal Vojtisek-Lom

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.

Off-cycle, Real-World Emissions of Modern Light Duty Diesel Vehicles

This paper investigates the emissions performance of modern European light-duty passenger vehicles with turbodiesel engines during real-world driving, notably during two extreme but not uncommon operating regimes: congested urban traffic and high-speed and performance driving. Four cars and one van were tested on a chassis dynamometer and/or on the road with a portable, on-board emissions monitoring system capable of online measurements of particulate and gaseous emissions. On all cars, operation at speeds and acceleration rates in excess to those within the applicable certification NEDC cycle resulted in higher concentrations of nitrogen oxide (NO) and particulate matter (PM). High-speed driving in excess of 120 km/h resulted in a marked increase in NO and PM concentrations, with further increases past 130-140 km/h. In urban driving, highest PM concentrations occurred at the onset of and during accelerations from low rpm. Aggressive, performance driving resulted in substantial increase in NO and PM emissions per kg of fuel compared to normal driving. No marked increases outside of NEDC regimes were, however, observed on the van. The results support the arguments against increase in 130 km/h freeway speed limits and for augmenting the EU certification tests for light diesel vehicles with supplemental cycles or tests.

FTIR analysis of surface functionalities on particulate matter produced by off-road diesel engines operating on diesel and biofuel

Fourier transform infrared spectroscopy is applied as a powerful analytic technique for the evaluation of the chemical composition of combustion aerosols emitted by off-road engines fuelled by diesel and biofuels. Particles produced by burning diesel, heated rapeseed oil (RO), RO with ethylhexylnitrate, and heated palm oil were sampled from exhausts of representative in-use diesel engines. Multicomponent composition of diesel and biofuel particles reveal the chemistry related to a variety of functional groups containing carbon, hydrogen, oxygen, sulfur, and nitrogen. The most intensive functionalities of diesel particles are saturated C–C–H and unsaturated C=C–H aliphatic groups in alkanes and alkenes, aromatic C=C and C=C–H groups in polyaromatics, as well as sulfates and nitrated ions. The distinguished features of biofuel particles were carbonyl C=O groups in carboxylic acids, ketones, aldehydes, esters, and lactones. NO2, C–N and -NH groups in nitrocompounds and amines are found to dominate biofuel particles. Group identification is confirmed by complementary measurements of organic carbon (OC), elemental carbon, and water-soluble ion species. The relationship between infrared bands of polar oxygenated and non-polar aliphatic functionalities indicates the higher extent of the surface oxidation of biofuel particles. Findings provide functional markers of organic surface structure of off-road diesel emission, allowing for a better evaluation of relation between engine, fuel, operation condition, and particle composition, thus improving the quantification of environmental impacts of alternative energy source emissions.

Comparative Analysis of Toxic Responses of Organic Extracts from Diesel and Selected Alternative Fuels Engine Emissions in Human Lung BEAS-2B Cells

This study used toxicogenomics to identify the complex biological response of human lung BEAS-2B cells treated with organic components of particulate matter in the exhaust of a diesel engine. First, we characterized particles from standard diesel (B0), biodiesel (methylesters of rapeseed oil) in its neat form (B100) and 30% by volume blend with diesel fuel (B30), and neat hydrotreated vegetable oil (NEXBTL100). The concentration of polycyclic aromatic hydrocarbons (PAHs) and their derivatives in organic extracts was the lowest for NEXBTL100 and higher for biodiesel. We further analyzed global gene expression changes in BEAS-2B cells following 4 h and 24 h treatment with extracts. The concentrations of 50 µg extract/mL induced a similar molecular response. The common processes induced after 4 h treatment included antioxidant defense, metabolism of xenobiotics and lipids, suppression of pro-apoptotic stimuli, or induction of plasminogen activating cascade; 24 h treatment affected fewer processes, particularly those involved in detoxification of xenobiotics, including PAHs. The majority of distinctively deregulated genes detected after both 4 h and 24 h treatment were induced by NEXBTL100; the deregulated genes included, e.g., those involved in antioxidant defense and cell cycle regulation and proliferation. B100 extract, with the highest PAH concentrations, additionally affected several cell cycle regulatory genes and p38 signaling.

Total Diesel Exhaust Particulate Length Measurements Using a Modified Household Smoke Alarm Ionization Chamber

ABSTRACT To evaluate the effectiveness of various means to combat the negative health effects of ultrafine particles emitted by internal combustion engines, a reliable, low-cost instrument for dynamic measurements of the exhaust emissions of ultrafine particulate matter (PM) is needed. In this study, an ordinary ionization-type building smoke detector was modified to serve as a measuring ionization chamber and utilized for dynamic measurements of PM emissions from diesel engines. When used with diluted exhaust, the readings show an excellent correlation with total particulate length. The instrument worked well with raw and diluted exhaust and with varying emission levels and is well suitable for on-board use. IMPLICATIONS The findings suggest the possibility for dynamic PM length measurements in diesel engine exhaust using a simple instrument using an ionization chamber analogous to the ionization chambers used in household smoke detectors, which are mass-produced and readily available on the market at costs in the

On-road and laboratory emissions of NO, NO 2 , NH 3 , N 2 O and CH 4 from late-model EU light utility vehicles: Comparison of diesel and CNG

10–50 (U.S.) range. Such an instrument could be used on-board or in a test facility for qualitative online measurements and for discrimination between pre-diesel particulate filter (DPF) and post-DPF levels and identification of high-emitting vehicles, becoming a tool analogous to the garage- and inspection-grade opacity meters and exhaust gas analyzers.

Inference of Steady-state Non-road Engine Exhaust Emissions Values from Non-stabilized Data

Exhaust emissions of eight Euro 6 light duty vehicles - two station wagons and six vans - half powered by diesel fuel and half by compressed natural gas (CNG) were examined using both chassis dynamometer and on-road testing. A portable on-board FTIR analyzer was used to measure concentrations of reactive nitrogen compounds - NO, NO2 and ammonia, of CO, formaldehyde, acetaldehyde and greenhouse gases CO2, methane and N2O. Exhaust flow was inferred from engine control unit data. Total emissions per cycle were compared and found to be in good agreement with laboratory measurements of NOX, CO and CO2 during dynamometer tests. On diesel engines, mean NOX emissions were 136-1070mg/km in the laboratory and 537-615mg/km on the road, in many cases nearly an order of magnitude higher compared to the numerical value of the Euro 6 limit. Mean N2O emissions were 3-19mg/km and were equivalent to several g/km CO2. The measurements suggest that NOX and N2O emissions from late-model European light utility vehicles with diesel engines are non-negligible and should be continuously assessed and scrutinized. High variances in NOX emissions among the tested diesel vehicles suggest that large number of vehicles should be tested to offer at least some insights about distribution of fleet emissions among vehicles. CNG engines exhibited relatively low emissions of NOX (12-186mg/km) and NH3 (10-24mg/km), while mean emissions of methane were 18-45mg/km, under 1g/km CO2 equivalent, and N2O, CO, formaldehyde and acetaldehyde were negligible. The combination of a relatively clean-burning fuel, modern engine technology and a three-way catalyst has resulted in relatively low emissions under the wide variety of operating conditions encountered during the tests. The on-board FTIR has proven to be a useful instrument capable of covering, with the exception of total hydrocarbons, essentially all gaseous pollutants of interest.

Operating History Artifacts of Large Engine Particulate Matter Emissions Measurement

This paper describes attempts to determine stabiliz ed emissions of non-road engines without waiting fo r stable emissions values to be reached, with the goal to shorten laboratory testin g time and/or to use real-world, in-service data fe aturing limited segments of steadystate operating conditions. The emissions from nonroad engines are often evaluated and reported in st eady-state operating conditions. Many larger engines are tested in the field, due to impracticality of dynamometer testing, resulting i practical limits for testing time at constant operating conditions. With lower fractions f elemental carbon (black soot) in the particulat e matter and increased deployment of catalytic aftertreatment devices, lon ger times are required for reaching stable values. This work seeks to infer stabilized emissions values from limited length segments of un steady but converging data. Theoretical considerati on of thermal factors and storage of material in the exhaust system, and emis sion data obtained in a laboratory and on a locomo tive engine tested in the field, suggest that the instantaneous emissions in steadyst te conditions tend to follow the exponential fun ction y(t) = y(steady) + [y(initial)-y(steady)]*exp(-const.*t) describing bo th mixing and Newton’s law of cooling. Several path ways of non-linear iterative regression has been investigated, generally leading to consistent results, albeit many individual segm nts of data yield inconsistent or no solution. It appears that when multiple segments of data longer than approximately two minutes are available, there is a high chance at arriving at a plausible steady state valu e of emissions concentrations. In such case, steady st te emissions can be derived from not fully stabilized data, such as from real-w orld operation of, for example, diesel locomotives, or from large engines tested in a laboratory. With large engines, this can possibly y ield considerable savings in testing expenses and i mproved emissions data. The findings are preliminary, and as of now, interpreta tion of data requires some skill.

Polycyclic aromatic hydrocarbons (PAH) and their genotoxicity in exhaust emissions from a diesel engine during extended low-load operation on diesel and biodiesel fuels

Exhaust emissions from internal combustion engines are one of the leading sources of fine particulate matter emissions in urban areas. Off-road engines account for a substantial portion of the total emissions, and are subject to increasingly strict legislation as well as voluntary emissions reduction programs. The benefits of various emissions reduction programs are typically quantified with simplified, short duration field tests. In an inquiry into the suitability of such tests, this paper examines experimental data collected by portable, on-board monitoring systems on truck, tractor, construction equipment, marine and locomotive diesel engines with rated power ranging from 130 to 1550 hp and displacement ranging from 4 to 163 liters. In engines operated extensively at low load, such as some locomotive engines, substantial amounts of solids and liquids accumulate inside of the engine and in the exhaust system. These deposits are then driven off during subsequent operation at high load. As a result, the emissions of particulate matter may be elevated for a rather long time, on the order of tens of minutes, which is longer than the duration of the individual modes of most field emissions tests. Therefore, the emissions of fine particles measured during short (units of minutes per mode) tests may be affected by the accumulated deposits. If this phenomenon is overlooked and not properly accounted for, the measurements may be less repeatable or comparable, and the particulate matter emissions based on such measurements may be overestimated. On the other hand, it is not clear that the problem can be remedied if the engine is diligently preconditioned prior to the measurement — in this case, the measured values do not account for “excess” emissions associated with extended low-load operation.Copyright