Ozone Layer

Ozone Layer

Introduction

Ozone in the stratosphere—the atmosphere above 30,000 feet (9,000 m)—is vital to the well-being of every plant and animal on the surface of the Earth. The ozone in the upper atmosphere shields the planet from invisible but harmful ultraviolet rays of the Sun. If such rays hit the Earth full force, they would kill fish and shrimp larvae near the surface of the oceans, stunt the growth of plants, and contribute to vision problems and skin cancer in humans. Through natural atmospheric processes, ozone molecules are continually created and destroyed. The sun's ultraviolet radiation breaks down oxygen molecules into atoms which then combine with other oxygen molecules to form ozone (Dentener et al., 2006).

The effects of radioactive rays can be rather more serious. Such ultraviolet radiation, if not stopped by the ozone layer, can break the bonds of the organic molecules, producing highly reactive fragments. It is also strong enough to be absorbed by the DNA chain and break it, can meet the fragments in a sequence different from normal. In fact, among the most serious effects are skin cancers, especially in fair-skinned people. If in the course of history have survived organisms whose DNA was sensitive to visible or infrared radiation, one can deduce the future that could have bodies that are not able to withstand UV radiation, in the case of the layer to disappear that protects us (Shea, 1999).

Discussion

Several studies have estimated that a reduction in the ozone layer in 1% could result in increased radiation dose biologically effective UV-B reaching the surface to sea level rise by around 2%, and if we try to assess the damage to other increases, we should consider not only how much ozone is lost, but where and when, as UV-B radiation varies naturally with the time of day, altitude and latitude and season (Grundman, 2001). Returning to the 2% increase in UV-B could represent a 4% increase in one type of basal cell carcinoma, and about 6% in squamous cell carcinoma type. With a 10% reduction in stratospheric ozone, some authors predicted increases in the relative incidence of skin cancers above 50% and 90% respectively (Shea, 1999). For example, in Germany, an estimated 10% reduction in stratospheric ozone could produce the appearance of 2000 cases of skin cancer over a year. As for the crops and, in general, plant species that inhabit the Earth, the damage would be more than obvious, especially as regards the species most sensitive to these radiations which would wither away (Dentener et al., 2006).

The fragile shield

Ozone forms a fragile shield, apparently intangible but very effective. It is so widespread by the 35 km. thickness of the stratosphere that if you compress it would form a layer around the Earth, not thicker than the sole of a shoe. The stratospheric ozone concentration varies with height, but never more than one hundred thousandth of the atmosphere in which it is located. However, this filter is thin enough to block virtually all harmful ultraviolet ...