Chlorine gas has a strong irritating smell that is similar to household bleach. The chlorine gas reacts with water in the air and forms bleach. These trace amounts are what create the odor.
It is not a good idea to smell chlorine gas. It is poisonous and corrosive. It has been used in chemical warfare. When inhaled, it contacts moist tissue in the body. The chlorine reacts with the water to form hydrochloric and hypochlorous acids, which cause tissue damage.
The smell of a chlorinated pool is not due to chlorine. This smell is due to substances called chloramines. These form when the chlorine in the pool reacts with substances like sweat, oil and makeup carried into the pool on people's bodies.