Colin Trier

Polycyclic aromatic compound profiles from a light-duty direct-injection diesel engine

The exhaust from a direct-injection light-duty diesel engine was sampled for polycyclic aromatic compounds (PAC) at three constant speeds and at five load settings for each speed, using a total-exhaust solvent-stripping apparatus. Exhaust samples were analysed for 3- and 4-ring polycyclic aromatic hydrocarbons (PAH) and dibenzothiophene by g.c.-m.s. in electron-impact mode. The PAC recoveries (per cent of fuel PAC) were highest at low loads and progressively declined with increasing load. At 1000 rev min−1 the averaged recoveries of four PAC (fluorene, dibenzothiophene, phenanthrene and pyrene) decreased from 0.95% at low load to 0.2% at full load. The recoveries of all PAC converged at high load, indicating survival of fuel PAC unchanged. A greater range of PAC recoveries was found at low loads, e.g. the recovery of pyrene at 1% of full load was significantly higher than that of other PAC. At 3000 rev min−1 the combustion efficiencies were greater and average PAC recovery decreased from 0.47% at low load to 0.13% at full load. The range of PAC recoveries at low load was greater at higher speeds. The difference between the percentage recoveries of dibenzothiophene and fluorene on the one hand and their monomethyl derivatives on the other was also most marked at high speed and low loads. The increased range of recoveries at high speed may be due either to pyrosynthetic contributions or to a range of combustion efficiencies of individual PAC structures.

The sources of benzo[a]pyrene in diesel exhaust emissions

Abstract Results are presented for the combustion of diesel fuel spiked with [7,10- 14 C]benzo[ a ]pyrene in a Perkins Prima DI diesel engine. Diesel exhaust samples were collected using the Total Exhaust Solvent Scrubbing Apparatus (TESSA) sampling system. Analysis of the exhaust samples was performed by radio-high performance liquid chromatographic techniques developed for this research. The major radioactive species in the exhaust was identified as [ 14 C]benzo[ a ]pyrene which had survived combustion. The survival was 0.04% of the original activity. The initial specific activity of the radiochemical in the fuel (248 μCi/mg) was similar to that in the exhaust (200 μCi/mg). It was concluded that benzo[ a ]pyrene in the fuel surviving combustion was the major source of benzo[ a ]pyrene in the exhaust. Contributions from other sources including lubricating oil and pyrosynthetic formation within the combustion chamber amounted to no more than 20%.

The Green Village project: a rural community's journey towards sustainability

In the South West of the UK, a growing number of rural and urban communities are exploring various pathways to a more sustainable living. The village of Belstone is among these pioneers of change through its Green Village project. It is a relatively affluent community and it has been a major challenge to engage people that are reticent to change their lifestyle and suspicious of the motives of the initiators. Based on a process of action research, this paper explores the attitudes and perceptions towards sustainability and how they influenced the peoples engagement. We demonstrate that the partnership was effective in enabling the villagers engaged in the project to take control over the process. Behaviour changes were reported by the villagers actively engaged with the initiative. The Green Village did not “snowball” to the entire community; however, many of those who chose not to engage associated the word “Green” with traits that they did not identify with.

A POROUS CARBON FILM FOR THE COLLECTION OF ATMOSPHERIC AEROSOL FOR TRANSMISSION ELECTRON MICROSCOPY

This paper describes a method of direct sampling of fine urban aerosol using porous carbon films, to increase collection efficiency and retain the structural integrity of the aerosol. A nuclepore membrane filter was coated with carbon and washed with chloroform to leave a clean porous carbon film on a 200‐mesh transmission electron microscope copper grid. The grid was attached to a clean nuclepore filter using carbon cement. Sampling was conducted for 1 h at 1.9 L min−1 flow rate. The porous carbon grid with sample was then assayed using transmission electron microscopy, and negatives were suitable for image analysis. The collection of fine airborne particles using this method is appropriate for electron microscopy, with a minimum of interference to the structure of collected particles.

The contribution of lubricating oil to diesel exhaust emissions

Abstract A new method has been developed for assessing the lubricating oil contribution to diesel exhaust particulates involving a computer program which creates data sets from the integrator output of high resolution gas chromatography (HRGC) analyses of sump oil and exhaust samples. The computer matches up to 60 peaks and enables the presence of lubricating oil in an exhaust sample to be quantified. Samples of diesel exhaust were used to develop the method and the lubricating oil contribution to exhaust emissions was calculated to be 0.6 – 1.0 g/hr which represented 28% of the total particulates.

Investigation of the fate of specific hydrocarbon fuel components in diesel engine combustion

Abstract A technique is described whereby, in separate experiments, [ 14 C]octadecane and [ 14 C]benzene were added as part of the fuel to a diesel engine and radiolabelled products of combustion examined by radio-GC. In an attempt to elucidate specific products of combustion [ 13 C]benzene was included with the [ 14 C]benzene so that 13 C-products of combustion could be sought by GC-MS. Recovered radioactivity from the exhaust was 0.002% for the benzene combustion and 0.008% for the octadecane combustion. Octadecane itself was recovered in a yield of 9 × 10 −4 %.

A study of the uptake of heavy metals by fodder maize grown with municipal solid waste/sewage sludge derived compost

This paper presents the preliminary findings from a study on the uptake of heavy metals by fodder maize grown with municipal solid waste/sewage sludge derived composts. From the data presented there is no evidence to suggest elevated levels of any of the metals investigated (As, Cd, Cr, Cu, Fe, Mo, Ni, Pb and Zn) in the maize grown on these plots, despite a small but significant build‐up of metals in the compost treated soils. The findings of this study are discussed in terms of current European legislation.

THE PHYSICAL NATURE OF AIRBORNE PARTICULATE MATTER (PM10) IN PLYMOUTH, UK

Plymouth aerosol has been directly collected on to transmission electron microscopy grids at both roadside and background sites at the University of Plymouth. Photographs of 50 randomly selected particles were taken. The particle images were collected and measured using a Quantimet 570 image analyser. Two box-counting procedures approximating to fractal dimensions were applied to the collected particle images. Comparison of the fractal dimensions of roadside and background particles shows there is a structural change in particles from road to background in the 220-320 nm size range. Within this range, roadside particles are both more dense and have a more convoluted surface than the same size aerosol in the background. It is reasonable to assume that roadside particles will therefore have a deeper lung penetration and greater surface loading of material than their counterparts in the background aerosol.