Ozone (03) is a gas and is a very active form of oxygen that is produced in the atmosphere when 3 atoms of oxygen are combined. Ozone is found in two different and divergent locations - up high in the stratosphere and down low in the troposphere. Stratospheric ozone serves to shield the Earth against biologically damaging, ultraviolet radiation from the sun and is referred to as ‘good’ ozone.
Ground-level ozone or ‘bad’ ozone, is a secondary pollutant, which means it is not emitted directly into the atmosphere but is created when primary pollutants react or interact. Bad ozone is created by a photochemical reaction involving elements known as ‘ozone precursors’. Specifically hydrocarbons referred to as volatile organic compounds (VOC's) and oxides of nitrogen (NOx), chemically react in the sunlight to form ozone. Warm temperatures stimulate this reaction, which is the reason that the highest ozone levels typically occur during the warmest times of the year. Motorized vehicle exhaust, industrial emissions, incomplete combustion, gasoline vapors and chemical solvents are some of the major sources of these ozone precursors.
Ground level ozone is a major health and environmental concern and is a primary ingredient of smog, the pollution that blankets many urban areas during the summer but even rural areas are subject to increased ozone levels because the wind carries ozone and the pollutants that form it hundreds of miles away from their original sources and in turn generates air pollution over a wide area.
Ozone reacts quickly and strongly with living tissues, plant-derived fabrics, dyes, rubber and many other man-made materials. Ozone oxidizes and destroys organic matter and when inhaled it can react with the lung tissue creating acute inflammation of or damage to the lungs as well as weakening the immune system making people more susceptible to respiratory illnesses such as bronchitis or pneumonia. Of particular concern is the fact that ozone primarily injures the bronchioles, the smaller airways and the alveoli, the tiny air sacs that send oxygen into the blood stream
People’s reactions to ozone pollution vary from individual to individual. Children, the elderly, people with existing lung disease, including asthma, chronic bronchitis, and emphysema and people who exercise outdoors a lot, are at a greater risk from high ozone levels. Ozone can irritate the nose and airways of people with allergies, especially those with asthma, and can increase the allergy symptoms. People with asthma have more asthma attacks when ozone levels are high. One study found a 28 percent increase in emergency room visits for asthma when ozone levels reach even moderate levels.
Frequent exposure to ozone pollution may cause permanent damage to the lungs. Even when ozone is present in low levels, inhaling it triggers a variety of health problems including chest pains, coughing, nausea, throat irritation, shortness of breath and congestion.