Community Research and Development Information Service - CORDIS



Project ID: 11380
Funded under: FP5-GROWTH
Country: Greece

Characteristics of exhaust particle emissions

Health effects of particulate emissions from road transport have been of interest for many years. Historically, particulate emissions from road vehicles have been controlled and progressively reduced through legislation based on particulate mass measurement. More recently, interest has extended into more specific characteristics of particle emissions such as size, number, surface area and composition.

The main aims of PARTICULATES project were:
- to increase understanding of particulate emissions from road vehicles,
- to provide a harmonised particulate sampling and measurement methodology,
- to provide input on representative emissions factors for particulates to enhance air quality modelling tools,
- to assess the effectiveness of technical measures for reducing particulate emissions.

In the PARTICULATES project, it was decided to study both the 'accumulation mode' and the 'nucleation mode' particles under transient and steady-state conditions. A harmonised sampling and testing methodology was developed. This was deployed in several laboratories to assess the effects of different vehicle technologies, fuels and operating conditions. The work was completed by some vehicle case studies, tunnel studies and non-exhaust emissions measurements.

Light-duty diesel vehicles and heavy-duty diesel engines equipped with particulate traps produced very low particulate emissions (mass and number) when operating on low sulphur fuels. A heavy-duty prototype Euro-5 engine using SCR/urea NOx after-treatment without a particle trap, produced very low particulate mass emissions, within Euro-5 limits, but its particle number emissions were higher than the DPF-equipped option. The effect of diesel fuel sulphur was most evident under high temperature operation. Under these conditions, fuels with nominal 50ppm or less sulphur gave significant reductions in particle mass and number emissions versus 300ppm sulphur fuels. In the advanced engine technologies, fuel effects on particulate emissions (other than sulphur) were small in absolute terms. Direct injection gasoline cars produced measurable amounts of particulate mass emissions, well below the Euro-4 diesel vehicle emissions limit, but higher than conventional gasoline cars and DPF-equipped diesel cars.

This was reflected in the numbers of carbonaceous and total particles.

Technical implications of results include:
- Particle number measurement techniques offer the potential for greater measurement sensitivity and discrimination, and are especially valuable for further research into cleaner vehicles and fuels.
- There is some evidence that the number of 'solid' particles does not always correlate with mass. However, further methodology development, including definition of suitable instrument calibration procedures and multi-lab validation, would be required prior to use of 'solid' particle number measurements in regulation.
- Developments in particle emissions performance of direct injection gasoline cars should be closely monitored.
- The relevance of the NEDC emission test cycle to real world operation should be reviewed.
- Further research continues to be needed on the health relevance of measurements of 'nucleation' mode particles, their chemical composition and their fate in the atmosphere.

Policy implications
- A major step in particulate emission control will be taken through the combination of diesel particulate filters and sulphur-free (10 mg/kg max S) fuels.
- Particle mass measurement is capable of distinguishing between engine technology levels up to DPF-equipped systems. Its continued use in regulation has the advantage of providing continuity with previous data

Related information

Reported by

Aristotle University
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