Alfa and particle filters...

In Germany there is an increasing discussion on particle filters for petrol motors and some car makers use marketing as this http://media.daimler.com/marsMediaSite/en/instance/ko/Particulate-filters-for-petrol-engines-Even-cleaner-thanks-to-filter.xhtml?oid=14317014

anyone here has some insights how a particle filter works, and what it means for rather new Alfa series? that would be great to get some insights...