I haven't tried as cheap HEPA filters appear to be harder to get hold of in the UK. Maybe due to different heating systems.
Clearing the Air: The Beginning and the End of Air Pollution by Tim Smedley is an excellent book if you are interested in this area.
I haven't tried as cheap HEPA filters appear to be harder to get hold of in the UK. Maybe due to different heating systems.
Clearing the Air: The Beginning and the End of Air Pollution by Tim Smedley is an excellent book if you are interested in this area.