The Script
Tian Tian: Good morning everyone. We are officers from the National Environment Agency Singapore. Today we will bring you through various aspects of the ozone.
They are mainly the importance of the ozone layer, the depletion of ozone from the reaction with CFCs, the sources, effects and solutions of unburnt hydrocarbons and photochemical smog.
Firstly, we would like to talk about importance of the ozone layer. As we know, the ozone layer is able to absorb ultraviolet radiation, commonly known as UV, at high altitudes. This prevents the harmful UV radiation from reaching the surface of the earth. UV radiation is very destructive to organic matter and humans are largely affected by UV radiation as exposure could lead to an increase in the risk of cancer, cataracts and an impaired immune system. Plants cannot live and grow in heavy ultraviolet radiation, nor can the plankton that serve as food for most of the ocean life. Thus the ozone layer is very important to life on Earth.
Seraphina: Secondly, we will be talking about the depletion of ozone from the reaction with CFCs. Chlorofluorocarbons (CFCs), commonly known as CFCs, are a family of chemical compounds developed back in the 1930s as safe, non-toxic, non-flammable alternatives to dangerous substances like ammonia for purposes of refrigeration and spray can propellants. Their usage grew enormously over the years. One of the elements that make up CFCs is chlorine. Very little chlorine exists naturally in the atmosphere. But it turns out that CFCs are an excellent way of introducing chlorine into the ozone layer. The ultraviolet radiation at this altitude breaks down CFCs, freeing the chlorine. Some problems involved with the depletion of the ozone layer are that under the proper conditions, chlorine gas has the potential to destroy large amounts of ozone. This has indeed been observed, especially over Antarctica. As a consequence, levels of genetically harmful ultraviolet radiation have increased. It also damages and mutates the DNA of marine bacteria and the larvae of starfish and urchins. Some research also shows that a decreased ozone layer will increase rates of malaria and other infectious diseases. According to the EPA, 17 million more cases of cataracts can also be expected. It also results in certain cases of skin cancer.
Michelle: Thirdly, we will go in depth towards the sources, effects and solutions of unburnt hydrocarbons. Hydrocarbons come from the combustion of engine exhausts, oil refineries, oil-fuelled power plants, evaporation from petroleum fuels, solvents, dry cleaning solutions and paints. Unburnt hydrocarbon may form ozone with oxides of nitrogen which is a central nervous system depressant. Since hydrocarbons come from engine exhausts, there are solutions to reduce engine emissions. Modern car engines now carefully control the amount of fuel they burn. This reduces the amount of emission as they try to keep the air-to-fuel ratio very close to the stoichiometric point, which is the calculated ideal ratio of air to fuel.
Xuanlin: Furthermore, we can also reduce the usage of air-conditioners, which releases CFCs as well. Refrigerators have also the ability to produce CFCs, therefore, one very good idea is to purchase environmentally friendly refrigerators available in the market which produce less CFCs. As burning of plastics will result in the release of CFCs, controlled quota of burning and the promoting of recycling will reduce the usage of plastic. Thus, it will be a solution to unburnt hydrocarbons as less hydrocarbons are burnt and thus less hydrocarbon are unburnt too. Treating the CFCs produced in power plants may also be one potential solution to be explored in the future, just like how sulfur dioxide is treated to be less harmful to the atmosphere. Lastly, photochemical smog is formed by reactions between sunlight and pollutants, like hydrocarbons and nitrogen dioxide.
Yujia: Photochemical smog is extremely harmful, leading to irritations of the respiratory tract and eyes. In regions of the world with high concentrations of photochemical smog, elevated rates of death and respiratory illnesses have been observed. Smog itself is simply airborne pollution which may obscure vision and cause various health conditions. It is caused by small particles of material which become concentrated in the air for a variety of reasons. Commonly, smog is caused by an inversion, in which cool air presses down on a column of warm air, forcing the air to remain stationary. Inversions are notorious in Southern California, where smog can sometimes get so severe that people are warned to stay indoors.
Yunting: Some measures have been taken around the world to reduce photochemical smog. Tight emissions regulations on vehicles and factories are one such step; many factories must use scrubbers and treatment systems before releasing air from their manufacturing facilities, for example. The use of harmful chemicals is also restricted in some regions of the world. Since these chemicals can create photochemical smog. Government agencies also monitor air quality through testing, citing companies which violate the law and issuing warnings when smog levels are dangerous.
Yunting: In conclusion, it is evident that the depletion of ozone layer is caused by chlorofluorocarbons, emissions from factories and photochemical smog. From human activities like the products we use daily, the gas emissions released during combustion to the pollutants in the air we inhale..Every action constitutes to ozone gas in the stratosphere declining at a rapid rate. To add on, chlorine atoms in CFCs catalyzes the chemical reactions taking place at the stratosphere. In other words, the tropospheric ozone formation is occurring at a slower rate than the depletion of ozone layer due to its complex chemical reactions such as photodissociation. The depletion of ozone is therefore viewed as an environmental issue that has to be constantly reviewed to develop in the solutions to better overcome the current health problems that were brought forth by the ozone depletion.
Note: all contents are self-produced with help of research, for reference only.
