Do Your Share For Cleaner Air W hat we typically call smog is primarily made up of ground-level ozone.
Ozone can be good or bad, depending on where it is located.
Ozone high above the Earth, known as the ozone layer, protects human health and the environment from ultraviolet radiation. Ground-level ozone can have harmful effects on plants and animals and can cause respiratory and other health problems. Because heat and sunlight are also important factors in ground-level ozone formation, ozone pollution is primarily a concern from April through October. EPA has issued a new, stricter air quality standard for ground-level ozone. The EPA lowered the acceptable ozone standard to address recent scientific evidence that cumulative lung damage can be the result of prolonged exposure to ozone air pollution.