Ozone By Aishat Isah

History of Ozone Ozone, the first allotrope of any chemical element to be recognized, was proposed as a distinct chemical substance by Christian Friedrich Schonbein in 1840, who named it after the Greek verb ozein ( "to smell"), from the peculiar odor in lightning storms. The formula for ozone, O3, was not determined until 1865 by Jacques-Louis Soret and confirmed by Schonbein in The adverse health effects of ozone have been studied since 1952.

Definition Ozone (O3) is a highly reactive gas composed of three oxygen atoms. It is both a natural and a man-made product that occurs in the Earth's upper atmosphere (the stratosphere) and lower atmosphere (the troposphere). Depending on where it is in the atmosphere, ozone affects life on Earth in either good or bad ways. Stratospheric ozone is formed naturally through the interaction of solar ultraviolet (UV) radiation with molecular oxygen (O2). The "ozone layer," approximately 6 through 30 miles above the Earth's surface, reduces the amount of harmful UV radiation reaching the Earth's surface.

Properties Ozone is a blueish colored gas that has a boiling point of (−112 °C). At atmospheric pressure, ozone can partially dissolve in water at standard pressure and temperature, the solubility of ozone and oxygen that contains morethan 20% ozone can become explosive in both fluids and gases.

Beneficial Effects The presence of the ozone layer in the stratosphere is very important for living organisms on earth. If brought to normal pressure at sea level, all of the existing atmosphere ozone would form a band no more than 3 mm thick. Although the concentration of ozone in the stratosphere is very low, it sufficient to filter out 99% of the dangerous ultra-violet radiation from the sun.

Beneficial Effects Ozone in the stratosphere can prevent radiation from penetrating to the earth's surface, which make damage to human e.g. skin cancer. The gaseous ozone not only absorbs UV radiation but also determines stratospheric temperature and thus plays a role in the circulation patterns of the stratosphere. Any change in ozone levels, allowing an increase or decrease in the transmission of radiation, would therefore cause disruption of the earth's energy budget, and lead to alterations in temperature levels and distribution patterns.

Adverse Effect Due to numerous human activities demolition, construction, farming among others has lead to the production of gases referred to as Green House Gases that moves into the stratosphere reacting to the Ozone Molecules and making these ozone molecules unavailable for protecting the earth crust. This process has resulted in many adverse effect both for man and the environment. UV radiation released by the Sun containing UV-A, the least dangerous form of UV radiation, with a wavelength range between 315nm to 400nm, UV-B with a wavelength range between 280nm to 315nm, and UV-C which is the most dangerous between 100nm to 280nm. UV-C is unable to reach Earth’s surface due to stratospheric ozone’s ability to absorb it.

Effects on Human Health Skin cancer Eye damage such as cataracts Immune system damage Reduction in phytoplankton Damage to the DNA in various life-forms

Over exposure may:  Increase risk of non- melanoma and malignant melanoma skin cancer Higher risks of malignant melanoma from severe sunburns – especially in childhood Risk of malignant melanoma has increased 10% Risk of nonmalignant melanoma has increased 26% malignant Non-malignant

 Suppress immune system  Accelerate aging of skin due high exposure  Cause an outbreak of rash in fair skinned people due to photo allergy – can be severe

Pterygium Cancer brought on by over exposure to UV-B