Ozone


Danielle Farrar
March 16, 1997

Triatomic oxygen, O3, is most commonly known as ozone. It has a
resonance structure, and can be drawn in two different ways:
O=O- O-O=O
It is a bluish, explosive gas at room temperature, and has a boiling point
of -119°C. It has a melting point of -193°C, and is a blue liquid. It\'s
critical temperature and pressure are -12.1°C and 53.8 atm, respectively. It
has a pleasant odor in concentrations of less than 2 ppm, and is irritating and
injurious in higher concentrations. The density of ozone gas is 2.144 g/L, and
the density of ozone as a liquid is 1.614 g/mL. It is extremely unstable, and
solutions containing ozone explode upon warming. It is found in varying
proportions on Earth, but it is about 0.05 ppm at sea level.
Ozone absorbs harmful ultraviolet radiation in the upper atmosphere, and
protects humans from skin cancer. But ozone is also the main ingredient of smog,
and causes serious health effects and forest and crop damage in the lower
atmosphere. Ozone is formed through the chemical reaction of volatile organic
compounds and nitrogen dioxide, in the atmosphere, in the presence of sunlight.
This reaction is called a photochemical reaction, because sunlight is required.
The product is known as smog. The notorious brownish color of smog is due to
nitrogen dioxide of the mixture. Increased temperature stimulate the reaction,
which is why ozone conditions are worse in the summer. It is an oxidant,
meaning it takes electrons away from other molecules, and disrupts key
structures in cells by starting chain reactions.
Ozone is a serious national problem. Half of the largest urban areas in
the United States exceed the ozone standards. The worst regions in the US
include California and the Texas Gulf coast, and the northeast and the Chicago-
Milwaukee area during the summer. The ozone condition varies from year to year,
as the temperature and weather fluctuate. This fluctuation also occurs
throughout the day, as emissions from morning traffic builds up, the levels rise.
Ozone emissions come from many things, such as automobiles, gas stations, power
plants, dry cleaners, paint shops, chemical manufacturing pants, oil refineries,
and other business that release volatile organic compounds.
The health effects of ozone are chest pain, coughing, wheezing, lung and
nasal congestion, labored breathing, sore throat, nausea, rapid breathing, and
eye and nose irritation. The symptoms occur when the levels of ozone are only
slightly higher than the legal standard. Living in San Diego during my
elementary school year, I personally felt the effects of ozone; the tightness of
the chest, wheezing, and labored breathing on certain hot, humid days. Days
would be labeled "smog days", and children wouldn\'t be able to play outside
during recess, the air was so polluted. Heavy exercise can drive ozone deeper
into the respiratory system, and interferes with lung operation, and children
growing up in smog-polluted areas have been found to have lost 10-15% of their
lung capacity.
Ozone severely damages crops, forests, and man-made materials. The
crops affected are ones such as soybeans, peanuts, corn, and wheat, and more
extensively to tomatoes, beans, snapbeans. Cash losses of these crops are
estimated at several billion dollars a year. Evidence points towards the fact
that ozone is severely damaging forest in the eastern United States, and ozone
is responsible for the reduced growth rate of commercial yellow pines in the
southeast U.S. Organisms such as lichens, and ecosystem processes such as
nutrient cycling, are also affected. Ozone can also damage materials, such as
causing cracking of plastics and rubber, and decomposition and fading of fibers
and dyes.
Ozone has been in the news a lot in the past decade or so. Not only the
effects of ozone as smog in the lower atmosphere, but ozone depletion in the
upper atmosphere. It seems rather ironic that something we have such an
abundance of that it becomes a problem, should also present the problem that we
are lacking in it. However, the focus of my research was primarily on smog and
the effects of the lower atmosphere. The health problems presented, the money
lost on crops, and forests, have made ozone quite a prevalent issue, mainly
because it affects everyone, all over the planet. This invisible gas has and
will continue to be a source of intense interest for scientists in the coming
years.
Contributing pollutants such as automobiles, power plants, and other things
I mentioned previously have led to controversy over these items. Huge amounts
of money have been put into research for decreasing the amount of ozone produced.
For instance, Los Angeles installed a subway-like system in order to decrease
traffic