A system to stop harmful particulate matter from being emitted by old diesel vehicles is being tested after a prototype was built by a university student.

Engineer Marco Cremona said he came up with the idea just over a year ago and engaged a student to make it the focus of his thesis.

The student, Christopher Borg, succeeded in proving Mr Cremona's idea by building a crude prototype based on a system of electro-statically charged plates which filter emissions and stop particulate matter.

Mr Cremona said the filter consisted of a system of positive and negatively charged wires and plates which caused the particulate matter to stick to the plates. When the charge was momentarily switched off, the particulate matter fell into a tray from where it was collected and safely disposed of.

Mr Cremona said the challenge now was to produce a smaller, more efficient system and to gauge its effectiveness with more accuracy so that it could be marketed.

He said the system could be especially useful to the owners of old commercial vehicles who would otherwise have to scrap their vehicles as new emission standards became law.

MEP Simon Busuttil this morning saw a demonstration of the prototype, having been invited to do so in view of his campaign in the European Parliament against harmful dust.

Engineer Cremona is a team member of Challenge 8000 whose objective is to climb Mt Everest in 2010 and thereby raise awareness on air pollution and the value of clean air.