Pollen Filters?

My first experience was with a Saab 900. The filter was big and made from some sort of oiled fibre. In 30000 miles it was choked with soot. Cleaning the inside back window produced negligible dirt compared with other cars. Pollen filters are now 'electrostatic'. They hardly get visually dirty and cleaning the back window produces loads of dirt. Have we taken a step backwards? Has anyone done tests on these systems?