Destructive Ozone

Depending on where ozone resides, it can protect or harm life on Earth.When it is close to the planet's surface, in the air we breathe, ozone is a harmful pollutant that causes damage to lung tissue and plants, and is considered to be "bad ozone."It is a powerful photochemical oxidant that damages rubber, plastic, and all plant and animal life.It also reacts with hydrocarbons from automobile exhaust and evaporated gasoline to form secondary organic pollutants such as aldehydes and ketones.The peroxyacyl nitrates are especially damaging photochemical oxidants that are very irritating to the eyes and throat.

Ozone pollution originating in urban areas can extend into surrounding rural and forested areas that are hundreds of kilometers downwind.Episodes of elevated ozone concentrations are associated with warm, slow moving high pressure systems and contain between 30 and 50 parts per billion by volume. Concentrations 3 to 8 times greater than natural background levels have been observed.During the summer heat wave of 1988, record ozone concentrations were recorded in the United States.Even Acadia National Park in Maine, and the Shenandoah mountains of Virginia, were affected by dangerous levels of ozone pollution.These rural areas are far removed from industrial regions and polluted cities. The ozone pollution recorded in Acadia most likely originated in New York City.That in Virginia may have migrated from refineries on the Gulf Coast.

Photochemical oxidants are the most significant cause of agricultural loss in the United States.Their damaging effects on vegetation and crops have been confirmed in the eastern United States, adjacent areas in Canada, and much of Europe.Ozone alone, or in combination with sulfur dioxide (SO₂) and nitrogen dioxide (NO₂), accounts for 90% of the annual crop losses in the U.S. that are caused by air pollution.

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