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A light-duty diesel vehicle with an oxidising catalyst exhaust after-treatment device was fuelled with reference diesel and run in a transient driving cycle (new European Driving Cycle). The particulate emissions were sampled from the diluted exhausts using an Electrical Low Pressure Impactor (ELPI) with separation of the particles according to aerodynamic size into 13-size levels ranging from 30 nm to 10 μm. The particles were collected on glass fibre filters used as substrates in the impactor. The particlulate mass collected for each size level was determined by weighing the filter prior and after sampling. Each filter was extracted in dichloromethane (DCM) in an ultrasonic bath. The obtained raw-extracts were thereafter fractionated in accordance to increasing polarity into two fractions (I-II) using an open tubular silica column. The fractions were chemically characterised using Gas Chromatography-Mass Spectrometry.

It is well known that most of the emissions from TWC cars are emitted during the cold start period. These emissions increase considerably at decreased ambient temperatures. To reduce cold start emissions an engine block heater may be used. In this present study the effects on the exhaust emissions of using a block heater were investigated. The exhaust was characterized by both regulated and some unregulated exhaust components. The car was tested according to the FTP-75 test procedure for regulated emissions at +22, +5 and -15°C ambient temperatures. At +5°C additional analysis of Polycyclic Aromatic Compounds (PAC) and 2,3,7,8-tetrachloro dibenzo-p-dioxin (TCDD) receptor affinity test was carried out. The test results showed reductions of CO and HC emissions when using a block heater. The reductions of these emissions were 60 and 65% respectively at the lowest ambient temperature investigated. NOx emissions were less affected and even increased marginally in some cases.

Exhaust emissions from a heavy duty diesel truck have been analysed, characterised and tested during transient driving conditions. In order to evaluate the effect of two different particulate traps, tests were carried out by analysis of selected pollutants in the emissions both with and without the particulate traps. Measurement was made of regulated pollutants (HC, NOx, CO), particulate emission and also some unregulated pollutants (polycyclic aromatic hydrocarbons (PAH), 1-nitropyrene and selected aldehydes and ketones). The mutagenic potential of the emissions was tested by means of Salmonella typhimurium (Ames test), utilizing tester strains TA 98, TA 100 and TA 100NR both with and without metabolic activation.. In general, it was found that the emissions of pollutants were decreased by the use of particulate traps.

A highly rated turbocharged diesel engine adapted for an alternative fuel based on ethanol and hexyl nitrate has been investigated with respect to the emission of organic compounds in the exhausts. The adaption involves: ignition nozzles with larger holes, a change of injection timing and more fuel injected per stroke. Emissions were measured at four different driving modes ie, 1, 8, 10 and 12 respectively, in the California Cycle. The exhaust composition are different compared to conventional diesel emissions. The main part of the organic pollutants consists of unburned ethanol and hexyl nitrate, acetaldehyde being the most abundant aldehyde.