In this posting we are going to talk about â€œgoodâ€ and â€œbadâ€ ozone in the environment. The discussion of bad ozone comes from the US EPA website. The discussion of the good ozone comes from the NASA website.
Ground-level or “bad” ozone is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight. Emissions from industrial facilities and electric utilities, motor vehicle exhaust, gasoline vapors, and chemical solvents are some of the major sources of NOx and VOC.
Breathing ozone can trigger a variety of health problems including chest pain, coughing, throat irritation, and congestion. It can worsen bronchitis, emphysema, and asthma. Ground-level ozone also can reduce lung function and inflame the linings of the lungs. Repeated exposure may permanently scar lung tissue.
Ground-level ozone also damages vegetation and ecosystems. In the United States alone, ozone is responsible for an estimated $500 million in reduced crop production each year.
Under the Clean Air Act, EPA has set protective health-based standards for ozone in the air we breathe. EPA and others have instituted a variety of multi-faceted programs to meet these health-based standards.
Throughout the country, additional programs are being put into place to cut NOx and VOC emissions from vehicles, industrial facilities, and electric utilities. Programs are also aimed at reducing pollution by reformulating fuels and consumer/commercial products, such as paints and chemical solvents that contain VOC. Voluntary and innovative programs also encourage communities to adopt practices, such as carpooling, to reduce harmful emissions.
Good ozone is found in the ozone layer. The ozone layer refers to the ozone within stratosphere, where over 90% of the earth’s ozone resides. The stratosphere is located between 10 and 50 km above the surface of the earth.
The ozone layer absorbs 97-99% of the sun’s high frequency ultraviolet light, light which is potentially damaging to life on earth. Every 1% decrease in the earthâ€™s ozone shield is projected to increases the amount of UV light exposure to the lower atmosphere by 2%. Because this would cause more ozone to form in the lower atmosphere, it is uncertain how much of UV light would actually reach the earthâ€™s surface. Recent UV measurements from around the northern hemisphere indicate small UV increases in rural areas and almost no increase in areas near large cities. The concern is that elevated UV levels may have adverse effects on plant and animal life on the earth.
The water treatment industry artificially creates ozone using an ozone generator to purify water by removing contaminants and inactivating pathogens. This is another example of good ozone in the environment. Spartan Environmental Technologies supplies ozone water treatment systems.