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The number and size distribution of particles emitted from a gasoline direct injection vehicle have been measured over the current European drive cycle and a range of steady state conditions. Measurements were made using the Scanning and Differential Mobility Particle Sizers (SMPS/DMPS) and an Ultrafine Particle Monitor (UPM). During the steady state testing, the number distribution of particles between 7nm-320nm was monitored using the SMPS and the integrated total particle count compared to the UPM measurement. Excellent agreement was seen between the two techniques, except at high speed (120km/h) where the UPM measured a greater number of particles than the SMPS indicating an increase in particles outside the range scanned by the SMPS. During the drive cycles, specific size ranges of particles were monitored using the SMPS/DMPS and the total particle count measured using the UPM. Comparisons between the techniques are also made for Diesel and gasoline vehicles.

A methodology has been developed to enable a single, gaseous sample to be collected from the diluted exhaust stream of heavy duty diesel engines operating over the European 13 mode ECE R49 emission cycle. The sample consists of timed contributions of dilute exhaust gas from each mode (weighted appropriately) to provide a gas sample that is representative of the complete cycle. The sample is collected in a Tedlar bag prior to GC analysis for individual hydrocarbon speciation. This methodology has also been extended to allow for the collection of a representative carbonyl sample using 2,4-dinitrophenyl-hydrazine (2,4-DNPH) impregnated cartridges. Results obtained from these systems are reported and compared to results obtained from light duty (diesel and gasoline) investigations.

Particulate matter in the air has become the focus of increased attention due to the concern of potential health effects. Among other sources, automotive vehicles are seen as a major contributor of fine particles. At present there is limited information available relating either to the number or size distribution of automotive particle emissions and detailed evidence has still to be established. To develop an understanding in the area of automotive particulate emissions a programme was carried out concentrating on tailpipe emissions as measured at the regulated particulate sampling point in a dilution tunnel. A previous literature study by CONCAWE had identified analytical techniques considered to be suitable for this application and which are capable of measuring both mass and number size distributions. Several variations of these techniques are available in the research field and the programme aimed to assess and compare their operation and performance.

Levels of ambient particulate matter have become the focus of increased attention over recent years as a result of studies suggesting an association between exposure and adverse health effects. Whilst research is continuing in many areas to identify a biological mechanism whereby this association can be explained, as yet there are only hypotheses. Causal relationships between observed health effects (i.e. increased hospital admissions, mortality, respiratory or heart problems) and any specific characteristic of the ambient aerosol have yet to be confirmed. Ambient aerosol has a complex chemistry and a wide range of physical properties, most of which undergo constant modification or transformation within the atmosphere. The particles in this aerosol may have originated either from natural or anthropogenic sources and may be either primary emissions (i.e. directly emitted to the atmosphere as particles) or secondary particles - formed by reaction of gas phase components.

This paper reports the results obtained in the EPEFE programme on the relationships between diesel fuel properties and light duty vehicle technology, which were used as input for further studies (i.e. air quality modelling) within the framework of the European Auto-Oil programme. The effects of density, polyaromatics, cetane number and back-end distillation (T95) were investigated in' 17 light duty vehicles and 2 light duty trucks which were selected to reflect the range of technologies and vehicle configurations anticipated to meet predicted emissions requirements beyond 1996. All were fitted with oxidation catalysts. The measured pollutants included total hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx) and particulates (PM) as well as hydrocarbon speciation and compositional analysis of particulates, tested to the European driving cycle for the year 2000. For the vehicle fleet as a whole, the largest percentage fuel effects were observed for HC, CO and PM.