Basic Facts About Various Types Of Pollution 


Air Pollution 

Air pollution kills and estimated 2.7 million to 3.0 million people every year about 6% of all deaths annually. About 9 deaths in every 10 due to air pollution take place in the developing world, where about 80% of all people live. 

About 2.5 billion people, almost all in developing countries, suffer from high levels of indoor air pollution. Indoor air pollution is due to burning wood, animal dung, crop residues, and coal for cooking and heating. Most of the victims of indoor pollution are women and girls, who have primary responsibility for cooing and tending the house. 

Outdoor air pollution harms more than 1.1 billion people, mostly in cities. The World Health Organisation (WHO) estimates that about 700,000 deaths annually could be prevented in developing countries if three major atmosphere pollutants carbon monoxide, suspended particulate matter, and lead were brought down to safer levels. The direct health cost of urban air pollution in developing countries was estimated in 1995 at nearly US $ 100 billion a year. Chronic bronchitis alone accounted for around US $40 billion. 

In cities that lack pollution controls, millions of people are at risk from outdoor pollution. Densely populated and rapidly growing cities such as Bangkok, Manila, Mexico City and New Delhi are often entombed in a pall of pollution from trucks and cars and from uncontrolled industrial emissions. In 1995, for example, the average ozone concentration in Mexico City was about 0.15 parts per million, 10 times the natural atmospheric concentration and twice the maximum permitted in Japan or the US. Ozone is a powerful secondary pollutant formed when oxides of nitrogen and unburned volatile organic hydrocarbons, mostly from vehicle exhausts, combine with oxygen under the action of sunlight. Ozone is a main component of smog. 

Another powerful secondary pollutant is acid rain, formed when sulfur dioxide and oxides of nitrogen combine with water vapor and oxygen in the presence of sunlight to form a diluted “soup” of sulfuric and nitric acids. They can fall as both wet (acid rain) or dry deposition. Other harmful pollutants include sulfur dioxide, suspended particular matter (soot, ash, and smoke from fires), carbon monoxide from vehicles exhaust, and lead, mainly from the exhaust of vehicles that burn leaded gasoline. 

Air pollution is not only a health hazard but also reduces food production and timber harvests, because high levels of pollution impair photosynthesis. In Germany, for example, about US $ 4.7 billion a year in agricultural production is lost to high levels sulfur, nitrogen oxides, and ozone. 

Water Pollution 

Globally, 2.3 billion people suffer from diseases linked to water. Providing safe drinking water and adequate sanitation would have major health benefits. Some benefits include and estimated 2.1 million fewer deaths from diarrhoeal diseases, 150 million fewer cases of schistosomiasis, and 75 million fewer cases of trachoma. 

Water borne diseases, also known as “dirty water” disease, result from using water contaminated by human, animal, or chemical wastes. These diseases cause an estimated 12 million deaths a year, 5 million of them from diarrhoeal diseases. Most of the victims are children in developing countries. 

In many places both surface and ground waters are fouled with industrial, agricultural, and municipal wastes. According to the World Commission on Water for the 21st Century, more than half of the World’s major rivers are so depleted and polluted that they endanger human health and poison surrounding ecosystem. In many large cities in the developing world the drinking water supply is contaminated. Only half of Southeast Asia’s 550 million people have access to safe drinking water. 

Pollution from Heavy Metals 

Illnesses traced to heavy metals date back to ancient Rome, where lead pots, pipes, and smelters were held responsible for loss of intelligence among children and for brain damage and abnormal behaviour among adults. Heavy metals released into the environment today come from uncontrolled emissions by metal smelters and other industrial activities, unsafe disposal of industrial wastes, and lead in water pipes, paint and gasoline. 

The heavy metals most dangerous to health include lead, mercury, cadmium, arsenic, copper, zinc, and chromium. Such metals are found naturally in the soil in trace amounts, which pose few problems. When concentrated in particular areas, however, they present a serious danger. Arsenic and cadmium, for instance, can cause cancer. Mercury can cause mutations and genetic damage, while copper, lead, and mercury can cause brain and bon damage. 

Lead additives in gasoline cause widespread health problems in some countries. In Thailand, for example, a 1990 study found that some 70,000 children in Bangkok risked losing four or more points of IQ (Intelligence Quotient, based on standardized tests) because they were heavily exposed to lead emissions from motor vehicles. In Latin America some 15 million children under the age of two are at risk of ill health from lead pollution. 

In the US leaded gasoline began to be phased out after the passage of the Clean Air Act in 1970. It was not until the mid 1980s, however, that the European Community followed suit. Elsewhere, leaded gasoline continues to be used extensively.


 Source: The Bangladesh Observer,September 16, 2001