The cooking fumes of my neighbors below are often discharged into our kitchen through the chimney we share. On such occasions I usually close the door of the kitchen. It seems to me their noisy smoke extractors switched on puff all the offensive air into our apartment. Recently I was contemplating to stick a piece of paper on the mouth of our ventilator to prevent the intruding smell. I have ceased to use it since son went to high school. Today I was urged by another unpleasant odor from the chimney and stood on a stool blocking the soft pipe of our machine close to the chimney with a tightened cord.