Sometimes we hear that ozone is good, as in the ozone layer, and sometimes we hear that ozone is bad as in air pollution
or smog. How can it be both good and bad? This depends on where it is in the environment and how it is formed. This
page will discuss the so called "bad ozone" or "ground level ozone". To learn about "good ozone" by clicking on this link.
In the Earth’s lower atmosphere, near ground level, ozone is formed when pollutants emitted by cars,power plants, chemical plants, and other sources react chemically in the presence of sunlight. Ozone pollution is a concern during the summer months when the weather conditions needed to form ground-level ozone—lots of sun, hot temperatures— normally occur.
Ozone can irritate your respiratory system, causing you to start coughing, feel an irritation in your throat and/or experience an uncomfortable sensation in your chest. Ozone can reduce lung function and make it more difficult for you to breathe as deeply and vigorously as you normally would. When this happens, you may notice that breathing starts to feel uncomfortable. If you are exercising or working outdoors, you may notice that you are taking more rapid and shallow breaths than normal. Ozone can aggravate asthma. When ozone levels are high, more people with asthma have attacks that require a doctor’s attention or the use of additional medication. One reason this happens is that ozone makes people more sensitive to allergens, which are the most common triggers for asthma attacks. Also, asthmatics are more severely affected by the reduced lung function and irritation that ozone causes in the respiratory system. Ozone can inflame and damage cells that line your lungs. Within a few days, the damaged cells are replaced and the old cells are shed—much in the way your skin peels after a sunburn. Ozone may aggravate chronic lung diseases such as emphysema and bronchitis and reduce the immune system’s ability to fight off bacterial infections in the respiratory system.
This is why ozone water treatment systems are designed to remove ozone before the vent gas is released into the environment.