Ozone: Friend or Foe?

bar harbor ozone

During periods of hot weather we frequently hear about outdoor air quality warnings and the mention of ozone. This gaseous chemical is has both positive and significantly harmful properties.

A bit of chemistry is necessary to understand this gas.  Ozone is a triatomic (consisting of three atoms) molecule consisting of three oxygen atoms in a very unstable state.  It has very different properties than the more familiar O2 atom that is essential for our respiration.  It’s formed when the more stable O2 is exposed to ultraviolet light or electrical discharges.  These two forms of energy cause oxygen to break apart chemically and reform as an unstable gas with very high oxidizing potential.  High oxidizing potential makes ozone useful as a disinfectant and has many industrial uses from cleaning clothing, uses as cleaning agents, and killing mold and bacteria in airstreams. Most public water drinking supplies are phasing out chlorine with ozone for purification, and there’s a chance your bottled water has been purified with ozone as well.  This list of uses has been growing steadily and quickly due to its effectiveness and relatively low cost.

Ozone has a characteristic smell that some people identify as sweet, while others compare it to a chlorine-like odor.  Many have experienced this smell after a close lightning strike.  The thousands of volts of electrical discharge from a lightning bolt create this gas.

As effective as ozone can be, it can be very harmful to animal mucous and respiratory systems and damaging to plants as well. People with compromised immune systems and/or respiratory ailments are especially affected by ozone, even at lower concentrations.

Ironically, several filter manufactures produced and sold ozone generators for use inside living and work places as a panacea for air filtration.  In theory, these devices could be highly effective at a relatively low cost.  In reality, these produced more harm than good and were essentially banned from distribution several years ago after a major confrontation between the marketing giant, Sharper Image, and Consumer Union, the editors of Consumer Reports.  This battle, along with deceptive marketing tactics, caused the 2008 bankruptcy of Shaper Image.

Much confusion arises over ozone as either beneficial or harmful in the context of outdoor air quality. While ozone is a gaseous contaminant of concern for plants and animals, it is essential in providing some shading of excessive solar rays from entering the earth’s atmosphere contributing to the greenhouse effect. The media regularly reports on these holes in the ozone layer and the impact on the planet.  The Downeast region of Maine, including Bar Harbor and the pristine Acadia National Park, has some of the highest recorded concentrations of ozone due to pollution from southerly states piggybacking on the jet stream flow.

Ozone provides both benefits and risks to our environments.  During hot weather, concentrations of ozone swell, causing concerns for respiratory health.  Staying indoors, especially in an air-conditioned environment helps dramatically, as well as shifting outdoor physical activity to early mornings.