How do cigarette filters work?

Filters were added to cigarettes in the Fifties when it was
discovered that smoking causes lung cancer, leaving cigarette
manufacturers under pressure to convince people that smoking
was safe. The filters are made of a synthetic fibrous mass called
cellulose acetate, which is a kind of fine plastic packed tightly so
that it looks like cotton wool. The material is designed to
accumulate the vapours and tar in the fibres before they reach
the smoker’s mouth. However, filters in no way lessen the
unhealthy smoke being inhaled. In fact, chemicals are added to
make cigarettes taste better and to increase the speed at which
nicotine is delivered to the brain, thereby keeping users hooked.