Cause and effect of Pollution.
...entering a chemical or combustion process (such as lead in gasoline), or they may be produced as a result of the process itself. Carbon monoxide, for example, is a typical product of internal-combustion engines. One effect of air pollution on our population is a decrease in human health. The consequence of exposure to dirty air is considerable. On a global basis, estimates of mortality due to outdoor air pollution run from around 200,000 to 570,000, representing about 0.4 to 1.1 percent of total annual deaths. As the range of these estimates indicates, it is difficult to quantify the toll of outdoor air pollution. The health impacts of urban air pollution seem likely to be greater in some of the rapidly developing countries where pollution levels are higher. The World Bank has estimated that exposure to particulate levels exceeding the WHO health standard accounts for roughly two to five percent of all deaths in urban areas in the developing world. However, these statistics alone do not capture the great toll of illness and disability that exposure to air pollution brings at a global level. Health effects span a wide range of severity from coughing and bronchitis to heart disease and lung cancer. Vulnerable groups include infants, the elderly, and those suffering from chronic respiratory conditions including asthma, bronchitis, or emphysema. For example, air pollution in developing world cities is responsible for some fifty million cases per year of chronic coughing in children younger than fourteen years of age. However, even healthy adults can suffer the negative effects. Many of air pollutions’ health effects, such as bronchitis, tightness in the chest, and wheezing, are acute, or short term, and can be reversed if air pollution exposures decline. Other effects appear to be chronic, such as lung cancer and cardiopulmonary disease. In fact, in the United States, two long-term epidemiological studies representing some of the most significant recent research on air pollution effects documented an increase in the death rate of those chronically exposed to dirty air. These studies, which compared death rates among many U.S. cities with widely varying pollution levels, found that mortality rates were seventeen to twenty-six percent higher in cities with the dirtiest air compared with those with the cleanest air, and those with the dirtiest air had significantly higher rates of lung cancer and cardiopulmonary disease. These increased risks translate roughly to a one- to two-year shorter life span for residents of the most polluted cities. Higher infant mortality rates have also been associated with high par...