The Wizard of Ozone

I live on the Eastern rim of the LA basin. For my long distance readers, that's Los Angeles, the City of Angels, in California on the West Coast of the US. 34^o N, 118^o W. LA has a lot to offer, both good and bad. There are the mountains, the beaches, Disneyland and Hollywood. There are also a lot of freeways and way too many cars. One of the bad things in LA is the smog. Smog is formed from the emissions of cars and trucks, and by the reaction of light with some of the by-products of hydrocarbon combustion from internal combustion engines.

Now in LA, in California, we like to think of ourselves as "Green". We have electric cars, I owned one myself, and hybrids. We have bike paths and bagel shops. We have buses and light rail and solar panels. "Eco", for ecological, is found in many a business or product name. But we also have some of the worst smog in California if not the Nation.

LA Smog - Ben Amstutz

The name smog comes from "smoky fog", coined back in the early 1900's to describe the haze that was found then, and still is, in many large industrialized cities. Photochemical smog is created when the emissions from vehicles and industrial plants, the Nitrogen Oxides (NOx) and the volatile organic compounds (VOC), are exposed to light and Oxygen, producing particulate matter and ground level Ozone. These components of smog can inflame breathing passages, cause shortness of breath, pain when inhaling deeply, wheezing, and cough. They also can cause eye and nose irritation and dry out the protective membranes of the nose and throat. Hospital admissions and respiratory deaths often increase during periods when smog levels are high.

Ozone, O₃, is a major component of smog. It is highly irritating and unstable, producing tissue damage in the lungs and respiratory track. It plays a significant role in the damaging effects of smog to those living in areas with high smog levels. It contributes to increased asthma, emphysema and other lung diseases. This is Ozone near the Earth's surface or "Tropospheric Ozone".

Ozone is not all bad, however. Stratospheric Ozone, better known as the Ozone Layer, which is found near the top of the atmosphere, protects the earth from 97% plus of the UV radiation coming from the Sun.
Ozone Cycle

In the Stratosphere, Ozone is important for protecting life. It is being diminished by chlorofluorocarbons and other chemicals that are used on Earth but when they are released into the atmosphere, they migrate to the Stratosphere and break down the Ozone Layer. Ozone has been measured to be decreasing by about 4% per decade. This results in increased UV exposure, sunburns and skin cancers among other hazardous effects. Holes in the Ozone Layer have appeared over the poles and cause considerable concern for environmentalists. Many of the "green" changes being promoted today in manufacturing are to help eliminate Ozone depletion in the upper atmosphere. All of this is not a done deal, however, as many groups dispute the findings and the consequences as part of the natural process of variation that happens in nature. Much like "Global Warming", Ozone depletion is being debated as to its cause and effects.

Getting back to ground level Ozone, there is much less debate about is effects. Besides its health consequences, there is evidence that Ozone can cause a significant reduction in agricultural yields because it interferes with photosynthesis and stunts overall growth of some plant species. It also damages rubber polymers, such as tires, resulting in cracks that weaken the integrity of the product, potentially leading to failure.

Ozone can be used as a disinfectant and purifier for water and has been used to reduce the chlorine demand in pools and municipal water systems. It also is used in Industry for its ability to oxidize and to break Carbon-Carbon bonds in hydrocarbons. Many hospitals use large ozone generators to decontaminate operating rooms between surgeries. The rooms are cleaned and then sealed airtight before being filled with Ozone, which effectively kills or neutralizes all remaining bacteria. It even is being studied for possible medical use in a number of illnesses, but with limited benefit so far.

For all of its negative press, Ozone has many beneficial uses and ultimately decomposes back into pure Oxygen, O₂, when its job is done. Much like the real Wizard of OZ, it's true identity is only seen when you look behind the curtain (of smog)!