Ozone Layer

The ozone layer is a layer in the atmosphere at an altitude of 19 to 48 km (12 - 30 miles) above Earth's surface that contain molecules of ozone. Concentration of ozone in this layer reaches 10 ppm and is formed under the influence of ultraviolet sun rays on oxygen molecules. This event has occurred since the millions of years ago, but a mixture of nitrogen molecules in the atmosphere that appears to keep the ozone concentration is relatively stable.
Ozone is a toxic gas that when positioned near the soil surface would be dangerous if inhaled and can damage the lungs. In contrast, the ozone layer in the atmosphere protects life on Earth because it protects from ultraviolet radiation that can cause cancer. Therefore, scientists are worried when they discovered that the chemicals Chloro fluoro carbons (CFCs) used as cooling medium and spray aerosol gas thrusters, giving the threat to this layer. When released into the atmosphere, the chlorine-containing substances will be broken down by sunlight that causes the chlorine can react and destroy ozone molecules. Every one CFC molecule can destroy up to 100,000 ozone molecules. Therefore, the use of CFCs in aerosols was banned in the United States and other countries in the world. Chemicals such as bromine halokarbon, and also nitrogen oxides from fertilizers, can also attack the ozone layer.
Depletion of the ozone layer in the upper atmosphere is expected to cause increased skin cancer and cataracts in humans, damage to certain crops, affecting plankton which will result in the marine food chain, and increased carbon dioxide (see global warming) due to loss of plants and plankton. Conversely, too much ozone in the lower atmosphere to help the smog, which is associated with respiratory tract irritation and acute respiratory diseases for those who suffer from cardiopulmonary bypass problems.