It is known that exposure to fine airborne particles with micron and submicron dimensions may present significant risks to human health. These particles emitted by industrial sources such as power plants, diesel engines, cement kilns, food processing factories and by various domestic sources can penetrate deep into the human respiratory system and their effect on humans is not fully understood. Particles with sizes less than two-and half micrometers (PM2.5) are of particular concern, for example in 2009 the UK Committee on the Medical Effects of Air Pollutants reported that these particles are more closely related to effects of mortality than larger particle fractions. This fine particulate matter can remain airborne for long periods of time, which significantly increases the probability of their inhalation and the health risk they pose. As in industrialized countries people spend the majority of their time indoors, it is important to minimise air pollutant levels in such closed environments. The present proposal is focused on the development of an impulsive micro-electrostatic precipitation (IMP) technology for the removal of fine particles from air. This technology is based on the use of nanosecond impulse corona discharges and a background DC voltage for effective electrical charging and transportation of airborne PM2.5 particles. High voltage impulses will allow application of significantly higher voltages (which could be as high as several tens of thousands of volts) to the active, corona electrodes in order to generate ions through ionization and dissociation of the ambient gas. It is expected that higher ionic concentrations produced by impulsive energisation will provide more efficient electric charging of the PM2.5 particles and will result in improved removal efficiency. Also, the use of sub-microsecond high voltage impulses will help to avoid catastrophic spark breakdown (which is similar to miniature lighting) in the IMP electrode system, these sparks lead to the collapse of the electric field and result in reduction of the production of ions. Conventional electrostatic precipitation systems have a pronounced minimum in their efficiency for particles with dimensions between a few hundred nanometers and a few micrometers, and it is anticipated that IMP technology will provide improved removal efficiency of airborne particles with these sizes. It is planned that the compact IMP air cleaning systems can be used in hospitals, schools, offices and homes.

Potential Impact:
The successful development of the impulsive micro-electrostatic precipitation (IMP) technology will have a significant impact on air cleaning technology. Airborne fine particles pose a potential health risk, and this risk is exacerbated by the increasing use of nano-particle based technologies. Particles of size less than two-and-half micrometers (PM2.5) have recently started to attract attention as they can be carried long distances, can stay airborne for long periods of time and can penetrate deep into the lungs. As a result, manufacturers of air cleaning systems for domestic and commercial use are continuously looking for more effective methods to reduce the concentration of PM2.5 airborne particulate matter. The IMP technology has the potential to dramatically increase the efficiency of reduction of PM2.5 particles in air which are difficult to remove using conventional electrostatic precipitation methods. The major beneficiaries from the successful outcomes of this project will be air cleaning and purification industries and society in general. Progress in technological developments associated with the impulsive micro-electrostatic precipitation will provide a platform for the development of highly efficient and reliable air-cleaning systems which can be used in indoor and closed space environments where it is necessary to reduce concentrations of PM2.5 airborne particles to the lowest possible level. Typical applications of such impulsive micro-electrostatic precipitators can found in hospitals, schools, offices and homes, public transport and other places where people are present over long periods of time and where air quality is a high priority. It is known for example, that in industrialised countries people can spend more than 20 hours per day indoor. Therefore it is important to ensure the quality of indoor air and the IMP technology has the potential to fulfil this task. The proposed one-year research programme is focused on the development of the scientific and engineering basis for the impulsive micro-electrostatic precipitation technology, and it is planned to establish links with industrial companies which develop, produce and use air-cleaning systems. It is anticipated that after successful completion of this programme, the development of practical IMP systems will be continued in collaboration with the industrial partners. Depending upon the level of resources from industrial partners, it is anticipated that it could take 3-4 years to develop a demonstration IMP system. The research assistant employed on this project will be involved in research and development of the impulse micro-electrostatic precipitation technology for the effective control of fine airborne particles. It is anticipated that the research assistant will have a unique opportunity to develop practical skills in the field of pulsed power engineering, fine particle characterisation, and electrostatic precipitation. He/she will work with state of the art pulsed power systems, high voltage diagnostic systems and a particle spectrum analyser. Training and experience obtained during this project will improve the research skills of the researcher and will increase his/her employability. Several manufacturers of the air cleaning equipment have been contacted and they have expressed significant interest in the proposed IMP technology. It is planned to work in close collaboration with these companies which will allow for better understanding of the practical problems and tasks which could be addressed through the innovative development of the impulsive micro-electrostatic precipitation technology. It is planned to disseminate the results of this project through research publications and presentations at relevant scientific conferences and technological workshops.