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What do we know about the specifics of the bonding process between a diatomic oxygen molecule (O2) and the third oxygen atom, the combination of which ends up as O3? Does it have to do with radiation? How exactly does it happen? What are the effects of inhaling ozone on the human body? I know that it is harmful to plants and even deadly to them, but what does it do to humans?
Answer 1:

You have asked some good questions! I have tried to answer your question with the help of an expert--a postdoctoral scholar in our research group at UCSB. She studies how marine animals protect themselves from solar radiation, so she knows a great deal about ozone.

High in the atmosphere oxygen molecules (O2) absorb energy from ultraviolet radiation (UVR) and are split into single oxygen atoms. These atom combine with existing O2 to form ozone.

The reactions are:
O2 + UV light -> 2 O
O + O2 -> O3

Ozone is both protective and destructive. It is beneficial by forming a filter for the most damaging wavelengths of UVR present in sunlight. The
amount of ozone in the layer at any one time and location is subject to natural variation caused by the solar cycle (sunspots), volcanic activity and atmospheric circulation patterns. Over the past 15 years the total amount of ozone screening the Earth from UVR has decreased significantly at high latitudes. These changes have been caused most likely by the chlorine(Cl) contained in synthetic chemicals called chlorofluorocarbons (CFCs).
CFCs have been used as refrigeration agents and propellants in aerosol sprays. They have a long lifetime in the atmosphere. When they diffuse into the stratosphere, sunlight causes the molecules to break up, releasing Cl atoms. Cl (and other molecules) reacts catalytically with and destroys ozone molecules.


Ozone can be destructive when it resides in the air we breathe because it is a powerful oxidant and a toxic gas. It can damage molecules in plant and animal cells as well as plastics and rubber by generating reactive oxygen radicals that can oxidize our tissues. Ozone is formed by
gases called nitrogen oxides (NOx) and volatile organic compounds (VOCs or hydrocarbons) emitted from car exhaust , tree, gasoline, solvents, paint...chemicals that in the presence of heat and sunlight react to form ozone.
NO2 absorbs sunlight and breaks apart to produce oxygen atoms that combine with O2 to form O3. Ozone can be highly irritating the sensitive tissues of our eyes, throats, and lung, which have direct exposure to them. In addition, it can react with hydrocarbons, such as those in automobile exhaust and evaporated gasoline to form secondary pollutants such as aldehydes like those used to preserve animal tissues.

General reactions:
Sunlight +NO2 + O2 --> O3 + NO
or

In sunlight, VOCs recycle NOX by reacting with NO to produce more NO2, fueling the original reaction to form more O3.

sunlight + VOCs + NO --> NO2 which leads to NO2+ O2 --> O3 + NO


How might ozone affect my health?Taken from the EPA brochure (see websites below).

Scientists have been studying the effects of ozone on human health for many years. So far, they have found that ozone can cause several types of short-term health effects in the lungs:

Ozone can irritate your respiratory system, causing you to start coughing, feel an irritation in your throat and/or experience an uncomfortable sensation in your chest.

Ozone can reduce lung function and make it more difficult for you to
breathe as deeply and vigorously as you normally would.

Ozone can inflame and damage cells that line your lungs. Within a few days,
the damaged cells are replaced and the old cells are shed-much in the way your skin peels after a sunburn.

Ozone can aggravate asthma. When ozone levels are high, more people with
asthma are more sensitive to allergens, which are the most common triggers for asthma attacks. Also, asthmatics are more severely affected by the
reduced lung function and irritation that ozone causes in the respiratory
system.

Ozone may aggravate chronic lung diseases such as emphysema and bronchitis and reduce the immune system's ability to fight off bacterial infections in the respiratory system.

Ozone may cause permanent lung damage. Repeated short-term ozone damage to
children's developing lungs may lead to reduced lung function in adulthood.
In adults, ozone exposure may accelerate the natural decline in lung function that occurs as part of the normal aging process.

Helpful websites:
http://www.epa.gov/airnow/health/smog1.html#3
http://www.ciesin.org/TG/OZ/overview.html
http://www.epa.gov/airnow/brochure.html
http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/ATM_CHEM/ozone_cycle.html
http://daac.gsfc.nasa.gov/CAMPAIGN_D

Answer 2:

I'd recommend that you check out 'ozone' on www.google.com, which is reported to be the best search engine now, because it sorts the results by how popular they are - how many hits they get. I found some vibrational
frequencies for hydrogen bonds by searching for that on google this week, and they were easy to find and useful to us.

Without searching ozone myself, I think the radiation breaks the diatomic oxygen bond and then the single oxygen atoms are extremely reactive and
combine with other diatomic oxygen molecules. And the ozone is also very reactive, since it is high energy (and extremely unstable...) and can get to a lower energy by giving away its third oxygen.

And so ozone is very reactive in living things and can oxidize our
molecules. Rancid fat is fat that has gotten oxidized, for example. I think an oxygen atom adds across a double bond between carbon atoms in fats and makes an epioxide, which is reactive and can oxidize other molecules.

So oxidizing molecules is one way of damaging them, which is why we don't
want high ozone levels. (Sometimes oxidizing is good, such as when our food gets oxidized to give us energy, but our bodies and enzymes aren't designed to use ozone for the oxidation pathways that turn food into energy.)

Here's a questions for you: Why do you think so many health food stores advertise special foods (Anti-oxidative juice at Trader Joes for example!) with anti-oxidants incorporated in them? Do you think these products work?

My main question about health effects is: I think there are also ozone
generators that are sold for 'purifying' the air in our rooms. So, are there ways in which a little ozone is good for us? Ozone is generated in thunderstorms, and the air has a special fresh and invigorating smell after a thunderstorm, partly due to the ozone.


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