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Essential oils are mainly used in the aromatherapy and natural medicine sector. However, as high quality oils are needed in this sector, there is a significant essential oil waste-stream which can be used in transport and agricultural sector specially in diesel engines. The aim of this paper is to evaluate a multi-cylinder diesel engine using Tea tree oil essential oil blended with diesel. The blend contained 90% diesel and 10% tea tree oil (by volume). The diesel engine used was a 160kw modern high speed common rail turbocharged diesel engine. The engine was operated at 1500 rpm and 4 loads. Property-wise, compared to base diesel, tea tree oil-diesel blend has lower viscosity, higher density significantly lower heating value and cetane number. There was minimal variation of brake thermal efficiency and brake specific fuel consumption between base diesel and tea tree oil-diesel blend. However, in-cylinder pressure for tea tree oil-diesel blend was significantly lower compared to base diesel. In most loads, tea tree oil-diesel blend emitted lower NOX but significantly higher CO and PM emission.

Size distributions of expiratory droplets expelled during coughing and speaking and the velocities of the expiration air jets of healthy volunteers were measured. Droplet size was measured using the interferometric Mie imaging (IMI) technique while the particle image velocimetry (PIV) technique was used for measuring air velocity. These techniques allowed measurements in close proximity to the mouth and avoided air sampling losses. The average expiration air velocity was 11.7 m/s for coughing and 3.9 m/s for speaking. Under the experimental setting, evaporation and condensation effects had negligible impact on the measured droplet size. The geometric mean diameter of droplets from coughing was 13.5 mu m and it was 16.0 mu m for speaking (counting 1-100). The estimated total number of droplets expelled ranged from 947 to 2085 per cough and 112-6720 for speaking. The estimated droplet concentrations for coughing ranged from 2.4 to 5.2 cm(-3) per cough and 0.004-0.223 cm(-3) for speaking. (C) 2008 Elsevier Ltd. All rights reserved.

Analysis of the particulate size and number concentration emissions from a fleet of inner city medium duty CNG buses was conducted using the newly available Diffusion Size Classifier in comparison with more traditional SMPS's and CPC's. Studies were conducted at both steady state and transient driving modes on a vehicle dynamometer utilising a CVS dilution system. Comparative analysis of the results showed that the DiSC provided equivalent information during steady state conditions and was able to provide additional information during transient conditions, namely, the modal diameter of the particle size distribution.

Early this year the Australian Department of Environment and Heritage commissioned a desktop literature review with a focus on ultrafine particles including analysis of health impacts of the particles as well as the impact of sulphur content of diesel fuel on ultrafine particle emission. This paper summarizes the findings of the report on the link between the sulphur content of diesel fuels and the number of ultrafine particles in diesel emissions. The literature search on this topic resulted in over 150 publications. The majority of these publications, although investigating different aspects of the influence of fuel sulphur level on diesel vehicle emissions, were not directly concerned with ultrafine particle emissions. A specific focus of the paper is on: ----- ----- summary of state of knowledge established by the review, and ----- ----- summary of recommendations on the research priorities for Australia to address the information gaps for this issue, and on the appropriate management responses.

Particles from compressed natural gas (CNG) engine emissions are smaller than those from diesel or even petrol engine emissions and range from 0.01-0.7 ~tm, with majority being between 0.020 and 0.060 p.m. (Ristovski et a12000). Very little data is available on particle emissions from CNG fuelled vehicles. An isolated study in this area by Greenwood et al (1996), indicated that the particle concentration levels emitted from CNG fuelled engines are similar to those from gasoline engines, and at high loads approach those of diesel engines. Recent studies conducted by Ristovski et al (2000) showed that the observed levels of particle emission were in terms of number of the same order as emissions from heavy-duty diesel engines. On the other hand emissions of CO and NOx for one of the tested engines, were considerably lower than the maximum allowed by the standards.