Environmental Issues

The term CFCs is an abbreviation of the word Chlorofluorocarbons. Chlorofluorocarbons together with other compounds that contain chlorine and bromine have been found to accelerate the depletion of the Ozone layer in the stratosphere.CFCs were developed in 1930s and  were widely used for household, commercial and industrial purposes through out the twentieth century. They are ideal for various applications due to their safety and stable thermodynamics properties. For instance, the CFCs have been used as blowing agents, coolants in homes, electronic cleaning solvents, and aerosol propellants and in commercial refrigeration. In 1970s, research findings confirmed that chlorine contributes to ozone destruction. As a result, CFCs have devastating effects on the environment (Carlisle, 2004).The emission of CFCs together with smog both cause environmental degradation. Smog refers to the combination of air pollutants to form fog and smoke. Smog leads to smoky dark atmosphere that is often witnessed in urban areas. This decreases visibility and causes health problems in humans. In this paper, the effects of CFCs and smog on humans and the environment will be discussed.

Discussion
Effects of CFCs on humans and environment
The introduction of CFCs in the early twentieth century led to their wide use in industries and at home. Increased use led to ozone destruction.CFCs are non-reactive in the troposphere  but intense ultraviolet radiation in the stratosphere  leads to the decomposition of the CFCs into atoms and molecules of chlorine (CFCs and Ozone depletion,2010).These components  trigger a chain of chemical reactions that break down the molecules of radiation-shielding ozone. The destruction of the ozone due to the release of CFCs has resulted to destructive biological effects of solar radiation (Miller, 2002).In humans, intense solar radiation is known to cause cancer. Stratospheric ozone depletion reduces the shielding of the earths surface against solar ultraviolet radiation (UV-B (222)).This increases the incidence of skin cancer in fair-skinned populations. Incidences of skin cancer in white populations have been on the increase due to exposure to ultra-violet radiation. For example, it is estimated that between 1982 and 1989, incidences of melanomas which is a form of skin cancer rose by 83 per cent in the US. Examples of CFCs that are widely used include CFC113, CFC12, CFC22 and CFC11.Other known effects of ozone depletion on human health includes eye disorders such as retinal damage and cataracts. In some cases, ultra-violet radiation due to ozone depletion affects the human immune system by decreasing its ability to fight diseases. Because CFCs account for about 15 percent of green house gases, an increase in global temperatures is likely to  an increase incidences of  tropical diseases .For the past three decades, industrialization has  made efforts to decrease  the levels of chlorofluorocarbons released a great challenge. The exposure of humans to ultraviolet radiation leads to premature appearance of aging of the skin. In addition, solar exposure increases wrinkles and skin dryness. Although the numoral system in the human immune system is not affected by ultraviolet radiation, the cellular immune system is sensitive  to ultraviolet radiation .Exposure to the radiation triggers the development of malignant skin tumors .

Solar radiation affects plants and this has had negative impact on vegetation. Radiation due to ozone depletion by CFCs reduces agricultural yields, a situation that has led to food shortages in various parts of the world. An increase in ultraviolet radiation reduces crop yields, damages construction material and deplete marine resources. The negative impact of ozone depletion on agriculture compromises on the food supplies in various countries and this result to food insecurity. The ever increasing world population has led to an increase in demand for food. There is no doubt that the release of CFCs has played a major role in global food shortages and hungerstarvation in the developing countriesCFCs can contribute to the intensification of green house effect which plays a major role in global climate change. Due to the negative effects of chlorofluorocarbons on the environment, partial restrictions on the use of CFCs in the early 1980s led to prohibition of their use as propellants. The response to ozone depletion led to the signing of the Montreal Protocol in 1987.The treaty demanded that the developed countries cut the production of ozone-depleting substances such as CFCs by 1996 while the developing countries were expected to cut down the production by 2010.

The negative impact of CFCs on the environment can no longer be ignored (McNeill, 2001).They contributes to air pollution and can take between six to eight years to reach the stratosphere. After reaching this layer, they can reside there for more than a 100 years. This makes them very destructive to the ozone layers due to the long term effects they have on the environment. The spread of vector borne diseases in plants and the contamination of water supplies cause environmental problems. Damage to the ozone makes the plants susceptible to insects, harsh weather, pollutants and diseases (Chlorofluorocarbons, 2010).
In marine ecosystems, ultraviolet radiation impairs the phytoplanktons.Phytoplanktons are important in the marine food chain hence their destruction leads to an ecological catastrophy in the system. Through out the 1980s, countries such as Australia, Mexico, Canada and European nations banned the use of CFCs in aerosol containers due to the devastating effects that have had on the environment.However, more efforts need to be put into place to address this critical problem.

Effects of Smog on humans and environment
The presence of smoke and fog in the environment has negative effects on humans. Smog is formed from industrial and vehicular emissions that are acted on by sunlight to form secondary pollutants that together with primary emissions form photochemical smog. Some of the most affected cities in the world are those in industrialized developed countries. They include Hong Kong, New Delhi, Beijing, Toronto, London, Mexico city, Tehran and American cities such as New York and Los Angeles. Health problems in humans that are caused by smog are numerous (Davis, 2002).Smog cause health problems in humans who live in areas that   experience high concentrations of smog. One major effect of smog on humans is its contribution to the development of lung cancer. The human body finds it difficult to fight diseases due to the effects of smog. For example, smog inflames and irritates the pulmonary membranes. This causes coughing, chest pains and throat irritation in humans. Exposure to smog also causes pneumonia and cold. For individuals who suffer from asthma, living in areas with high concentration of smog can have lead to health complications. For example, Mexico City is estimated to be one of the cities that have had large levels of smog. This has had the elderly people and the children discouraged to live in the city. An increase in smog levels in the urban areas leads to the carrying away of smog to other areas near the urban areas. This means that the urban populations that live around the affected urban centers are likely to experience health problems emanating from the presence of smog. Effects of smog vary according to the time of    exposure, age and ones state of health.
       
Smog is also referred to as the ground level ozone. When exposed to smog, agricultural crops such as peanuts, cotton, soybeans, tomatoes and wheat are adversely affected. Smog aggravates health problems such as bronchitis, asthma and emphysema. As research studies to determine the effect of smog on human health continue to be carried out, scientists have agreed that air pollution caused by smog has adverse effects on human health. Respiratory health problems have been linked to the presence of smog. It causes damage to the mucociliary system which plays the important role of cleaning the air tracts. This reduces the ability of the lungs to resist damage. Ground level ozone when present in ambient concentrations cause fibrosis and the inflammation of the lungs and air pollutants caused by smog leads to premature aging of the lungs as well as decreased lung function. People who suffer from chronic respiratory, heart and pulmonary diseases as susceptible to health problems caused by smog. Other health complications caused by smog include tiredness, constriction of the chest, nausea, coughing and headaches.

Air pollutants are responsible for adverse effects on the environment and humans. Nitrogen dioxides together with the ground level ozone are considered to reduce the ability of the immune system to fight viruses and bacteria in the respiratory system. Although these symptoms are short term, the long term  effects of the pollutants on humans and environment  is worrying (Michael and Konstantinos,2008).Chemical  reaction  of nitrogen oxides, sunlight and volatile organic compounds in the atmosphere form air borne particles and ground level ozone. Smog causes acid rain which affects plants and the environment when it interferes with the vegetation and animal life .Acid rain results to sever damaged vegetation on barren land and ground level ozone cause damage to leaves, leaf discoloration and reduction of photosynthesis due to loss of leaves. Plants become vulnerable to diseases, pests and environmental disasters such as drought.Furthermore, death of plants has been witnessed in areas with smog. For example, an increase in vulnerability to stress in Jeffrey Pines and Ponderosa tree species in Sierra Nevada in the past has been attributed to smog.Sulphur dioxide in the smog corrodes metal and damages industrial instruments and machinery. Nitrogen oxides and sulphur dioxide are responsible for acid precipitation. Acid rain may have a P.H of less than or equal to 5.5.This has serious ecological impact on forests and aquatic systems when the optimum P.H in the natural ecosystems is interfered with. Deviation from P.H values in the environment interfere with the proper functioning of hormones and enzymes and proteins. Effects of smog are worse when it is warm or sunny because the upper air is usually warm enough to prevent vertical circulation. In aquatic systems, successful reproduction in organisms may be hindered when soil content is affected by acid precipitation and the growth of acid-tolerant species is triggered. Smog interferes with the ability of plants to manufacture and store food. This undermines reproduction, growth and overall growth of plants. For economically important crops such as wheat, cotton and soybeans, production is drastically reduced when soil fertility is reduced.

Conclusion
Chlorofluorocarbons and smog have for many years had devastating effects on humans and the environment. Man-made CFCs during the 1930s increased their use in industries, at home and household purposes. Many developments that are currently witnessed can be attributed to the use of CFCs through out the century. The effect of CFCs on the ozone layer has led to efforts by countries to lower the production of CFCs but negative effects of the chlorofluorocarbons continue to be experienced as countries try to compete in the global economy. Smog which is also referred to as ground level ozone is a major cause of health problems in humans and destruction to the environment. In order to address the problem of CFCs and smog, there is need for countries to work together to reduce CFCs production and  smog air pollution which continue to affect plants, animals and to  put at risk the lives of millions of people.