An Ozone Action Day, which can be declared by a local municipality, county or state, is observed at certain times during the summer months, when weather conditions (such as heat, humidity, and air stagnation) run the risk of causing health problems.he ozone layer protects people from the sun's most damaging ultraviolet rays. Because the ozone layer is located high in the atmosphere, people are not directly exposed to it. Ground-level ozone, however, is a health hazard because people breathe it.