How does pollution in large cities affect human health?
Pollution, a worldwide problem which has been concerned with since 1972 (Seitz 2008:156), has significant effects on human health in large cities. It may be defined as several different types of pollutant in environment mainly caused by industry and agriculture, having a harmful impact on public health. It is because cities, most of which, have depended on the two types of industry to develop the economy that the problems of urban pollution are serious. For example, the percentage of inhabitants in Calcutta with respiratory diseases is 20 times as much as that of India average (Bashkin 2002: 70). There are 4 main kinds of pollution: air, water, and land pollution. This essay will examine how the pollutions mentioned above affecting human health in large cities. It is acknowledged that air pollution affects public health in large cities. For instance: it is suggested that in London hospital 2 percent of myocardial infarctions will be induced by air pollution(Poloniecki et al.,1997 sited in Ayres 2006: 24). This paragraph will introduce 3 main pollutants: sulphur oxides, lead, and carbon monoxide. Firstly, sulphur oxides may trigger heart diseases and asthma (American Thoracic Society, 1996; Pope and Kockery, 1999; Pope,2000 sited in Romieu and Hernandez-Avila, 2003). It is estimated that in London more than 4000 people died of sulphur oxides in 1952 (Seitz 2008:159; Patz and Balbus, 2001). Lead, as a pollutant caused by industry, does harm to human bodies, especially to children’s brains (Seitz 2008: 162). Bashkin (2002) states that “ in Bangkok lead pollution could cause 200,000 to 500,000 cases of hypertension, 300 to 900 cases of heart attack and stroke, and 200 to 400 deaths per year (ESCAP, 1995). Furthermore, it also could cause average loss of 3.5 IQ points per child before the age of seven, i.e., an estimated total loss of 400,000 to 700,000 IQ points per year.” On the other hand, Outdoor air pollution does harm to public health, whereas indoor air pollution may be a more serious problem in slums of large cities (Seitz, 2008). In those areas, people who depend on wood and straw heating or cooking breathe the polluted air which may includes CO and does harm to their health. It is suggested that in Japan, women will get higher risk of lung cancer when they use wood to cook (Subue,1990 sited in Bashkin, 2002).
Water pollution, may be another pollution which has great effects on public health. As a result of industrialization, safe drinking water is only available in less than 30 percent of largest cities in China (Seitz 2008). There are three prime contaminations: arsenic, mercury and pathogen, which will be introduced in this paragraph. Arsenic pollution is caused by smelting industry. It is widely acknowledged that the deep-water in Taiwan contains this substance which may damage blood vessels and gastrointestinal tissue resulting in substantial effects on brain, skin and heart and limbs (Hu, 2002). Another pollutant, mercury, also an important part of industry pollution, may cause “multiple sclerosis, systemic lupus, or chronic fatigue syndrome” (Hu, 2002). It may be exemplified by Minamata disease which is resulted from this substance, caused nearly 50 deaths in Minamata, Japan in 1950s (Oxford University,2009; Seitz ,2008). Different from arsenic and mercury, pathogen is a contamination produced by agriculture or households. Hill (2004) mentions that “epidemics of cholera, typhoid fever, and amebic dysentery” may be caused by pathogens in drinking water. Furthermore, in Milwaukee, United States, 400,000 residents were ill and nearly 100 people died because of pathogens in 1990s. Land pollution, a problem which is placed in developing countries such as China and Philippines, (Hill, 2004) may be defined as a kind of pollution produced by industrial pollution, agricultural pollution, and domestic pollution. Since the close relationship between soil and water, land pollution, to some degree, can leads to water pollution. It is well known that the diffusion of heavy metals in solid waste can directly influences the quality of drinking water. As the examples mentioned above, arsenic and mercury, both come from solid waste and do harm to public health in large cities.
On the other hand, unscientific combustion of solid waste may also leads to air pollution. For instance, it is widely acknowledged that the combustion of plastic releases poisonous gas such as dioxin (Hill, 2004). In conclusion, there are several pollutions affect human health in large cities. Firstly, air pollution affects public health in respiratory and brain. Sulphur oxides and carbon monoxide have significant influence on respiratory and may lead to lung cancer. Secondly, water pollution could damage human health because it may contain toxic substance, e.g., arsenic and mercury or pathogens which are related to infectious diseases. Another main pollution is land pollution which has close association with air and water pollution and also affects human health. In short, air, water and land pollution in large cities affect human health via making people absorbing poisonous substance and microbe.
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