المساعد الشخصي الرقمي

مشاهدة النسخة كاملة : Pollution



عاشقة المسك
30-10-2009, 03:51 PM
The Real Dangers of Air Pollution




It doesn't take a rocket scientist to figure out that there are better things you could do for your health than take deep breaths on a smoggy day. A growing pile of research suggests that even relatively low levels of air pollution may be more harmful than previously realized, to XXXX heart and lungs. The latest salvo from researchers, published this week in the New England Journal of Medicine, focuses on how particulate matter from air pollution affects lung function (http://health.usnews.com/usnews/health/healthday/071205/cleaner-air-leads-to-healthier-lungs.htm). The new research buttresses studies (here (http://XXXXXXX.nejm.org/cgi/XXXXXXX/abstract/357/11/1075) and here (http://XXXXXXX.nejm.org/cgi/XXXXXXX/abstract/356/5/447)) published earlier this year by the same journal showing that air pollution contributes to heart problems. How much should you worry? U.S. News asked leading experts to put this latest news in context


What is particulate pollution?
According to an American Lung Association report (http://lungaction.org/reports/stateoftheair2007.html), particulate pollution refers to the mix of solid and liquid particles in the air that can come from natural sources, such as dust storms or wildfires, or from such human activity as the burning of fossil fuels in factories or the use of diesel engines. Other particulates are produced when certain chemicals and substances react with one another in the atmosphere.
What is the danger to my heart and lungs?
The effect of low levels of particulate pollution found in many urban areas is not unlike secondhand smoke, experts say. Studies show that short-term adverse effects from particulates include diminished lung function, coughing, wheezing, cardiac arrhythmias, and heart attacks. Long-term exposure can also worsen asthma, slow normal lung growth, damage lung airways, and increase the risk of dying from lung cancer and cardiovascular disease.
How big is the risk to me?
Certain populations, such as the very old and the very young, are the most vulnerable to air pollution. However, even the most alarming studies conducted in the most polluted areas suggest that the average person's individual risk from exposure is very slight. Relative risk numbers often seem more frightening than they actually are, says Erik Rifkin, an environmental scientist and the coauthor of a book about assessing health risks titled The Illusion of Certainty: Health Benefits and Risks. For example, an earlier study published in the New England Journal of Medicine found that short-term exposure to traffic fumes tripled the risk of heart attacks in heart-attack survivors. What's easily forgotten, says Rifkin, is that the risk was extremely small to start with. Jogging or having sex, for example, could elevate the risk of a heart attack by a similar amount, says Robert Brook, a cardiac physician at the University of Michigan.
What's the big deal if the risk to an individual is small?
From a public health perspective, even a tiny increase in risk multiplied by millions of people translates into tens of thousands of unnecessary illnesses, hospitalizations, and premature deaths, experts say. The Environmental Protection Agency estimates that each year some 65,000 Americans have cardiac events associated with uncontrolled air pollution levels.
How can I protect myself?
Short of moving to the countryside or at least away from busy roads (http://health.usnews.com/usnews/health/articles/070129/29highway.htm), shielding yourself from the effects of air pollution is not easy. Masks won't work, as many particles can slip right through. At the very least, suggests Murray Mittleman, a cardiologist at Harvard University, people who regularly exercise outdoors near highways (http://health.usnews.com/articles/health/2007/09/13/exercising-in-traffic-is-bad-for-the-heart.html) may want to consider remapping their route.
How can I find out about the quality of the air in my local area?
The American Lung Association has a Web tool (http://lungaction.org/reports/sota07_basics.html#particle to) that allows you to type in your ZIP code and get a detailed report on the air quality in your area. You'll find everything from grades for particulate and ozone pollution (Chicago gets an F for particulates, for example, while Cheyenne gets an A) plus a breakdown that shows how many unsafe pollution days the region has had and how many people in the area are at high risk.




The atmospheric concentration of carbon dioxide, the major greenhouse gas directly affected by human activities, has increased by about 30% since the beginning of the pre- industrial era around 1750 because of the combustion of fossil fuels and changes in land- use practices. During the same period of time human activities have also increased the atmospheric concentrations of other greenhouse gases such as methane and nitrous oxide, and regional pollutants such as sulfate aerosols. Increased atmospheric concentrations of greenhouse gases tend to warm the atmosphere, while increased concentrations of aerosols tend, in some regions, to cool the atmosphere. The Earth's climate, which has been relatively stable during the past 10,000 years is now changing. The Earth's surface temperature this century is as warm or warmer than any other century during the six hundred years; the Earth's surface temperature has increased by about one degree Fahrenheit over the last century; and the last few decades have been the hottest this century. In addition, there is evidence of changes in sea level, glaciers are retreating world-wide, and the incidence of extreme weather events is increasing in some parts of the world. Computational models that take into account the observed increases in the atmospheric concentrations of greenhouse gases and aerosols simulate the observed changes in temperature quite well, suggesting that there is a discernible human influence on the Earth's climate.
Greenhouse gas concentrations are projected to increase significantly during the next century in the absence of policies specifically designed to address the issue of climate change. For example, carbon dioxide emissions are projected to range from 6 to 36 billion tons of carbon per year in the year 2100: compared to current carbon dioxide emissions of 6 billion tons of carbon per year. Climate models project that the global mean surface temperature could increase another 1.5 to 6.5 oF by 2100: a rate significantly faster than observed changes over the last 10,000 years. Sea level is projected to increase by another 15 - 95 cm by 2100. While the incidence of extreme temperature events, floods, droughts, fires and pest outbreaks is expected to increase in some regions, it is unclear whether there will be changes in the frequency and intensity of tropical storms, cyclones, and tornadoes.
The overwhelming majority of scientific experts believe that human-induced climate change is inevitable. The question is not whether climate will change in response to human activities, but rather where (regional patterns), when (the rate of change) and by how much (magnitude). It is also clear that climate change will adversely affect human health (especially increases in vector-borne diseases such as malaria, dengue and yellow fever); ecological systems (changes in the composition and geographic distribution of many ecosystems, especially forests and coral reefs, with likely reductions in biological diversity); and socio-economic sectors, including agriculture (regional disruptions in food production, especially in the tropics and sub-tropics), and human settlements (the loss of land and the displacement of tens of millions of people due to increases in sea level).
In summary, human-induced climate change is an important new stress, particularly on ecological and socio-economic systems that are already affected by pollution, increasing resource demands, and non-sustainable management practices; most ecological and socio- economic systems are sensitive to XXXX the magnitude and rate of climate change; successful adaptation to climate change depends upon technological advances, institutional arrangements, availability of financing and information exchange; and developing countries are more vulnerable to climate change than developed countries



Pollution is the introduction of contaminants into an environment that causes instability, disorder, harm or discomfort to the physical systems or living organisms.[1] (http://en.wikipedia.org/wiki/Pollution#cite_note-0#cite_note-0) Pollution can take the form of chemical (http://en.wikipedia.org/wiki/Chemical) substances, or energy (http://en.wikipedia.org/wiki/Energy), such as noise, heat, or light energy. Pollutants, the elements of pollution, can be foreign substances or energies, or naturally occurring; when naturally occurring, they are considered contaminants when they exceed natural levels. Pollution is often classed as point source (http://en.wikipedia.org/wiki/Point_source_(pollution)) or nonpoint source pollution (http://en.wikipedia.org/wiki/Nonpoint_source_pollution).


Who follow guidance! " Surah TA-HA, 20: 47

The first Ayah cited above is interpreted according to the conditions existing now here In USA and other industrialized countries of the world. This writer strongly feels and is convinced (unless someone proves to the contrary) that the Ayath is referring to the environmental pollution in general and to the smog or air pollution in particular. The smog is plainly visible and it is enveloping the people. This clearly poses a grievous or serious health hazard to humanity. If not checked and controlled, it may pose a serious threat to the very existence of mankind on planet earth.

ENVIRONMENTAL POLLUTION
Environmental pollution is a term that refers to all the methods by which people pollute their environment or surroundings. People with gases and smoke dirty our clean air, our pure water is tainted with chemicals and other substances, and the virgin soil is damaged with too many fertilizers and pesticides. People also pollute their surroundings by other different methods. For example, they ruin nature's beauty by scattering junk and litter in the water and on the land. People operate motor vehicles and machines that fill the air with unpleasant noise. Almost everybody causes environmental pollution in someway or other.
Today environmental pollution is one of the most serious problems facing mankind. Air, water, and soil are essential to the survival of all living creatures on planet earth, but unfortunately they are harmed by pollution. Air polluted beyond tolerable levels can cause illness, and even death. Polluted water kills fish and other marine life and is dangerous to human health. Pollution of soil decreases the amount of land available for growing crops, vegetables and fruits. Our naturally beautiful world is becoming ugly by environmental pollution. Everyone is now conscious and wants to reduce pollution. But the pollution problem is XXXX serious and also complicated. It is complicated because much of pollution is caused by things that benefit mankind. For example, automobile exhaust causes a large percentage of all air pollution. However, the automobile provides transportation for millions of people all over the world. Discharge from factories is responsible for much of the material that pollutes air and water, but factories provide jobs and produce goods that people want. The use of fertilizer or pesticide can ruin soil, but fertilizers and pesticides are important aids to the growing of crops, fruits and vegetables. In order to end or greatly reduce pollution immediately, people must stop using many things that benefit them. Unfortunately, most people do not want to do that. But pollution can be reduced in a planned manner in several ways. Scientists and engineers can work together to find methods to decrease the amount of pollution that such things as automobiles and factories cause. Governments should pass and enforce laws that require manufacturers and Individuals to stop, or reduce on certain polluting activities. And most important of all is individuals and people's organizations must work to persuade their representatives in government, and also persuade manufacturers, to take action toward reducing pollution.

HISTORY
People have always polluted their environment or caused some environmental pollution. Since prehistoric times, human beings have put wastes in water and generated smoke by burning fuel. However, in early civilization people did not live crowded together, and they had no pollution- causing machines. Therefore, pollution was negligible and it was spread out over large areas. During ancient times, pollution problems first arose when large numbers of people started to live together in cities. With the growth of the cities, pollution also increased proportionately with them. However, the environmental problems were not serious or widespread until eighteenth century and early part of the nineteenth century. This period in history is called the Industrial Revolution, which began In England and spread to other European countries and the United States. The notable feature of the Industrial Revolution was the development of factories and overcrowding with factory workers in cities. At that time coal was the prime energy fuel to power most of the factories and to heat most of the homes in the cities. Because of the burning of coal, the air over such industrial cities as London became filled with huge amounts of smoke and soot containing sulfur dioxide and nitrogen dioxide. An additional problem was poor sanitation facilities, which allowed raw sewage to get into water supplies in some cities, which sometimes happens in the developing countries even now. The polluted water causes typhoid fever and other diseases. In the early part of the twentieth century, air pollution in industrial cities in the United States became a particularly serious problem. During the post economic depression period (1930's), smoke and smote emanating from factories, steel mills, power plants, railroads, and heating plants filled the air over many Eastern and Midwestern cities. It was reported that in some cities such as Pittsburgh and St. Louis, the air pollution was so thick that the motorists had to use headlights to see during the daylight hours.
After the end of the Second World War, air pollution from coal burning has been greatly diminished in most parts of the world. Cleaner fuels such as oil and natural gas are being used in nearly all railroads and many industries and home heating plants now. Those factories, which use coal, have taken steps to control the pollution from their furnaces. In many countries, epidemics from disease-carrying germs in city water supplies are no longer a major problem. Sanitary Engineering is advanced, so that cities now treat their water and keep it as free from germs as possible.
Inspite of these technological advancements, environmental pollution has become increasingly serious and widespread. Technological improvements have helped cause this increase. In addition, the population growth in urban areas is tremendously increasing. A rule of thumb is more the people more is the waste produced of every kind. Public awareness of environmental pollution has grown considerably. Dramatic environmental tragedies that occurred during the 1960's and the 1970's have pointed up the seriousness of the pollution problem. These include the oil spills that ruined the beautiful beaches and killed wildlife and waterways that had become nearly dead from solid wastes.
During the late 1970's the inhabitants of the city of Seveso in Italy were threatened after an explosion at a local chemical factory that released a poisonous and carcinogenic gas called dioxin. Chemical wastes that leaked from a former disposal site called Love Canal, in Niagara Falls, New York, resulted in many families moving out of their homes located in the area. Chemicals, such as polychlorinated biphenyls (PCB's) were discharged in the wastewater of certain industrial plants, found their way into the bodies of fish and other animals in various parts of the United States. In 1984, a leak of poisonous gas from a pesticide plant in Bhopal, in Madhya Pradesh State, in India, killed over 3,600 people and injured over 25,000 people. In April 1986, an explosion and fire at a XXXXXXX power plant at Chernobyl, near Kiev, in the Soviet Union, released large amounts of radioactivity into the atmosphere and over 36 people died because of this accident and several hundreds were injured and hospitalized. During the same year (1986), toxic chemicals released into the Rhine River killed thousands of fish and eels. The reason for this chemical spill has been traced to a fire at a chemical storage warehouse near Basel, Switzerland.

PUBLIC CONCERN
People have always polluted our environment. But for large part of history, pollution was not a major problem. Most of the people lived in uncrowded rural areas and the pollutants (waste products) they produced were scattered widely. At that time pollution-causing machines were not invented, such as industrial plants or motor vehicles. Industrialization and the development of crowded cities in the 1700's and the 1800's made pollution a major problem to man, plants and animals. Factories and human beings in these urban cities released huge amounts of pollutants into small areas. With the advent of automobiles and the rapid development of urban areas made pollution steadily worse. By the middle of the twentieth century, pollution had affected the water in every major lake and river and the air over every major city In the United States and other Industrial nations. Since man landed on the moon, millions of people have become alarmed by the dangers of pollution. The United Nations and a large number of countries are joining hands and working together to reduce pollution. There are several kinds of environmental pollution. They are air pollution, soil pollution, water pollution, and pollution caused by solid wastes, noise, and radiation. All parts of the environment are closely related to one another, ecologically. Ecology is the study of the relationships among living things, and between living things and other parts of the environment.
Because of the ecological relationships, a kind of pollution that chiefly harms one part of the environment may also affect others. Take for example, air pollution. Air pollution harms the air. However, rain washes pollutants out of the air and deposits them on the land and in bodies of water. On the other hand, wind blows pollutants off the land and puts them into the air.

AIR POLLUTION
Air pollution turns clear, odorless air into hazy, smelly air that harms health, kills plants, and damages property. Human beings cause air pollution by pouring hundreds of millions of tons of gases and particulates into the atmosphere each year. Particulates are tiny particles of solid or liquid matter. Smog is one of the most common forms of air pollution. Combustion (burning) is responsible for most of the air pollution. The burning of gasoline to power by motor vehicles and the burning of coal to heat buildings and help manufacture products are examples of such processes. In a combustion process, each time a fuel is burned, some type of pollutant is released into the air. The pollutants vary from small amounts of colorless poison gas to clouds of thick black smoke. Weather conditions can help to decrease the amount of pollutants in the air. Wind is responsible for scattering the pollutants, and rain and snow wash them into the ground. Unfortunately, in many areas, pollutants are discharged into the air faster than weather conditions can dispose of them. As we are witnessing everyday, in all crowded cities throughout the world, for example, millions or thousands of automobiles, factories, and furnaces are adding tons of pollutants into a small area of the atmosphere each day. Sometimes, weather conditions cause pollutants to build up over an area instead of clearing them away. One such weather condition -called thermal inversion- occurs when a layer of warm air settles over a layer of cooler air, which is near to the ground. The warm air holds down the cool air and prevents the pollutants from rising and scattering. A serious pollution problem occurs when a thermal inversion prevails over a city that is pouring tons of pollutants into the air.

HEALTH EFFECTS OF AIR POLLUTION
Factories, homes, and office buildings discharge sulfur dioxide and nitrogen dioxide into the air. Sulfur dioxide harms the respiratory systems of humans and animals. Sulfur dioxide turns into sulfur trioxide, which combines with water vapor to form sulfuric acid. Sulfuric acid is well known to cause corrosion of XXXXls. Automobiles, motor vehicles and aeroplanes emit hydrocarbons, nitrogen dioxide and carbon monoxide into the air. Carbon monoxide causes headaches and dizziness in humans. Nitrogen dioxide harms the respiratory systems of humans and damages plants. Hydrocarbons injure plants. Nitrogen dioxide combines with hydrocarbons and sunlight to form smog. Smog irritates the eyes of people, damages their lungs, and causes headaches. It also injures the plants. Combustion of garbage and trash results in the discharge of particles, and mercury into the atmosphere. Mercury harms the nervous systems of humans. Particulates injure the respiratory systems of humans, reduce visibility, and affect climate. As mentioned earlier, air pollution also harms plants. Poisonous gases in the air can restrict the growth of, and eventually kill nearly all kinds of plants. To give few examples, forests in Tennessee, citrus groves near Los Angeles, and vegetable gardens in New Jersey have all been seriously damaged by air pollution.
XXXX gases and particulates burn people's eyes and irritate their lungs. Particulates can settle in the lungs and worsen such respiratory diseases as asthma and bronchitis. Some experts are of the opinion that particulates may even help cause such diseases as cancer, emphysema, and pneumonia. It has been observed in cities throughout the world, long periods of heavy air pollution have caused illness and death rates to increase dramatically.
It has also been observed that most materials get dirty and wear out more quickly in polluted air than in fresh air. Construction engineers say that polluted air even harms such hard and strong materials as concrete and steel. Statues and other art objects that stood outdoors for centuries have been removed and taken indoors because air pollution is threatening to destroy them. One of the seven wonders of the world, the Taj Mahal, located in Agra City In India is decaying due to sulfur dioxide polluted air hovering over it. Air pollutants affect weather. Changes in the average temperatures of an area are affected by XXXX gases and particulates. Particulates scatter the sun's rays and reduce the amount of sunlight that reaches the earth. Such interference with sunlight may cause average temperatures in a city to drop. Carbon dioxide and other gases, allow sunlight to reach the surface of the earth, but prevent the sunlight's heat from rising out of the atmosphere and flowing back into space. This phenomenon is called the greenhouse effect. Greenhouse effect is known to cause average temperatures to rise.

WATER POLLUTION
As a result of water pollution the amount of pure, fresh water that is available is reduced for such necessities as drinking and cleaning, and for such activities as swimming and fishing. Water is affected by pollutants that come mainly from industries, farms, and sewerage systems. It is well known that factories dump huge amounts of waste products into bodies of water each year. The wastes that are dumped into water reservoirs include chemicals, wastes from animal and plant matter, and hundreds of other substances. Wastes from farms include animal wastes, fertilizers, and pesticides. A large amount of these materials drain off from farm fields into nearby bodies of water. Sewerage systems carry wastes from homes, offices, hospitals, and factories into water. Almost every city has a waste treatment plant that removes some of the most harmful wastes from sewage. This does not remove completely materials that harm the water.
Natural cycles work to absorb small amounts of wastes in reservoirs of water. During a natural cycle, wastes are turned into useful or at least harmless substances. Aerobic bacteria use oxygen to breakdown natural wastes such as dead fish and decay them down into chemicals, including nitrates, phosphates, and carbon dioxide. These chemicals, called nutrients, are used as food by algae (simple organisms) and other green plants in the water. Microscopic animals called zooplankton eat algae as food. Small fish such as minnows eats zooplankton. The small fish in turn, are eaten by larger fish. The larger fish eventually die and are broken down by bacteria. The cycle then begins again. This same natural cycles work on wastes discharged into water by people. Chemicals are broken down by bacteria. Bacteria also break down other wastes and turn them into nutrients, or else into substances that will not harm fish or sea plants. On the other hand, if too much waste matter is poured into the water, the whole cycle will begin to break down, and the water starts to become dirtier and dirtier. The bacterium that works to decay the wastes consumes too much oxygen during the decaying process. As a consequence of this, less oxygen is available for the animals and plants in the water. Due to lack of oxygen the animals and plants die, adding even more wastes to the water. In the end, the water's entire oxygen supply is used up and, without oxygen, anaerobic bacteria, rather than aerobic bacteria, decay wastes. The disadvantage of the anaerobic decaying process is that it causes wastes to give off smelly gases.
A process called nutrient enrichment, or eutrophication, takes place by nutrients present in the water. People also add nutrients to water, such as nitrates from agricultural fertilizers and phosphates from detergents in sewage; greatly increase the growth of algae in water. Growth of larger amounts of algae also results in the death of large amounts of algae. The dead algae become wastes, and, as they decay they use up the water's oxygen supply.
When heated water is added to a body of water, it upsets the cycles. Heated water can kill animals and plants, which are accustomed to living at lower temperatures in the water. Heated water reduces the amount of oxygen that water can hold. The addition of heated water is called thermal pollution. The source of most heated water is industries and XXXXXXX power plants that use water for cooling.
Another major pollutant of water is oil. Oil enters oceans primarily as a result of oil tanker accidents. Such oil spills ruin our beautiful beaches and kill birds and marine life.

SOIL POLLUTION
Soil pollution damages the thin layer of fertile soil that covers much of the earth's land and is essential for growing crops, vegetables and fruits. Nature takes thousands of years to form the soil to support food crops, but man can destroy it in a few years. In nature, cycles keep soil fertile. Bacteria and fungi decay these wastes such as animal wastes and dead organisms, breaking them down into nitrates, phosphates, and other nutrients. The nutrients feed growing plants, and when the plants die the cycle begins again. The use of large amounts of fertilizers decreases the ability of bacteria to decay wastes and produce nutrients naturally. Pesticides harm bacteria and other helpful organisms in the soil. Erosion causes much damage to soil. Careless farming and land construction cause erosion.

SOLID WASTES
The most visible form of pollution is solid wastes. Garbage and trash results in billions of tons of solid material each year. Much of this waste ends up littering roadsides, floating in lakes and streams, and collecting in ugly dumps. Some examples of solid wastes are junked cars, tires, and refrigerators. Stoves, cans and other packaging materials, and scraps of XXXXl and paper. When solid waste is stored' dumps, it provides home for disease-carrying animals, such as cockroaches and rats. When solid waste is destroyed by burning it, the smoke causes air pollution. Wastes dumped into water results in water pollution. Each American produces about 45 pounds (20 kilograms) of solid waste each day. Production of solid waste is increasing rapidly. In addition, materials that decay and burn are replaced by plastics that will not decay and that give off harmful gases when burned. Other kinds of pollutants such as noise, radiation, acid rain, pesticides, and such XXXXls as mercury and lead will be covered in a sequel.





Pollution
Herbicides, Herbicides, and More Herbicides

Now that plants are being genetically engineered to be herbicide resistant, herbicide use may actually triple. Farmers will no doubt use more herbicide when they think their crops can handle it.

First Herbicides, Now Pesticides

Companies are now engineering crops that manufacture their own pesticides and may be classified as pesticides by the EPA. This means more pesticides into our food and fields than ever before.

Changes in Our Environment

With completely new organisms being created all the time, local ecologies may be damaged. New organisms may compete with others that have never had the competition, causing unknown changes in the environment.

Gene Pollution Cannot Be Cleaned Up

Once GE organisms, are integrated into the environment it is impossible to contain or recall them. Unlike chemical or XXXXXXX contamination, negative effects are irreversible, and just as bad, almost completely unknown.
Other Problems
To Much Junk

Although scientists are beginning to understand the functioning of DNA, most is still unknown. 97% of human DNA is called "junk" because scientists have no idea what it's purpose is. Yet the biotech companies have already planted millions of acres with genetically engineered crops, and they intend to engineer every crop in the world.
For more on world domination, see Monsanto: The Future of Our Food. (http://library.thinkquest.org/25365/monsanto.html)

What's Wrong?

The problems with GE arise from a lack in understanding of the fundamental workings of life itself. There is so much we do not know, yet companies are trying to feed the world, based on a technology which is far from perfected. Many top scientists from around the world agree.
See what the Scientists Say (http://library.thinkquest.org/25365/scientists.html)





Dangers of Water Pollution

Virtually all water pollutants are hazardous to humans as well as lesser species; sodium is implicated in cardiovascular disease, nitrates in blood disorders. Mercury and lead can cause nervous disorders. Some contaminants are carcinogens. DDT is toxic to humans and can alter chromosomes. PCBs cause liver and nerve damage, skin eruptions, vomiting, fever, diarrhea, and fetal abnormalities. Along many shores, XXXXlfish can no longer be taken because of contamination by DDT, sewage, or industrial wastes.
Dysentery (http://www.factmonster.com/ce6/sci/A0816516.html), salmonellosis (http://www.factmonster.com/ce6/sci/A0843249.html), cryptosporidium (http://www.factmonster.com/ce6/sci/A0814175.html), and hepatitis (http://www.factmonster.com/ce6/sci/A0823412.html) are among the maladies transmitted by sewage in drinking and bathing water. In the United States, beaches along XXXX coasts, riverbanks, and lake shores have been ruined for bathers by industrial wastes, municipal sewage, and medical waste. Water pollution is an even greater problem in the Third World, where millions of people obtain water for drinking and sanitation from unprotected streams and ponds that are contaminated with human waste. This type of contamination has been estimated to cause more than 3 million deaths annually from diarrhea in Third World countries, most of them children


Pollution dangMicroscopic air pollutants from trucks, cars, power plants and wood burning may pose greater health problems than previously believed, according to state researchers.



Images
(http://www.sfgate.com/cgi-bin/object/article?f=/c/a/2008/05/23/BAFB10RFT5.DTL&o=0)View Larger Image (http://www.sfgate.com/cgi-bin/object/article?f=/c/a/2008/05/23/BAFB10RFT5.DTL&o=0)



More Bay Area News

Grant Building's faux frills true to history (http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2009/02/08/BA0A15HD3R.DTL&type=newsbayarea) 02.08.09
Falun Gong stages own Chinese New Year parade (http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2009/02/08/BA6215PK80.DTL&type=newsbayarea) 02.08.09
Bridge off-ramp to Embarcadero to reopen Monday (http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2009/02/08/BANP15P7T4.DTL&type=newsbayarea) 02.08.09
S.F.: Tipsy poles straightened (http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2009/02/08/BAT815P3Q6.DTL&type=newsbayarea) 02.08.09





The new estimates were released Thursday in response to a request from the California Air Resources Board, which was seeking up-to-date research on premature deaths associated with inhaling particles one-thirtieth the width of a strand of hair.
Based on 60 studies worldwide and advice from a team of experts, including the World Health Organization, the researchers concluded that the new risk factor for fine-particle pollution is 70 percent higher than previously estimated.
The report, also reviewed by scientists at UC Berkeley, could serve as the basis for strengthening state - and perhaps federal - air-quality regulations.
"Particle pollution is a silent killer," state Air Resources Board Chairwoman Mary Nichols said after receiving the report Thursday at a board meeting in Fresno.
Most of the premature deaths linked to California's bad air occur in regions surrounding San Francisco Bay, Los Angeles and the San Joaquin Valley. The drop in fine particulates statewide in the last decade, particularly in cities, has been 30 percent.
One region that saw even greater improvement, the San Joaquin Valley, decreased 45 percent over the same time period due to new regulations, according to state air officials. The board added even more regulations Thursday by restricting wood burning to up to 35 days in the winter as well as requiring employers to start carpools.
Direct link

The state's study found a direct correlation between increased pollution from specks of dust, soot, XXXXls and soil and a greater number of hospitalizations, emergency visits and missed school days.
Health problems were generally related to respiratory illnesses and heart disease. Some studies reported bouts of asthma and bronchitis. Even small increases can affect children, the elderly and people with chronic diseases, researchers say.
The cost of hospitalizations, physician visits and lost work days connected to airborne specks of dust and tiny droplets could reach $70 billion a year, health officials said.
Numbers of premature deaths are difficult to estimate because the scientific knowledge isn't far enough along to determine a safe level of the tiny particles. California's average small-particle concentration is about 14 micrograms of PM2.5, or particles less than 2.5 micrometers in diameter, per cubic meter of air. The San Francisco Bay's average over the past three years is 10.69 micrograms.
Assuming that a safe level is 7 micrograms of PM2.5 per cubic meter of air - half as clean as the state's air - means that there would still be about 14,000 to 24,000 premature deaths every year in the state associated with these small particles, the study said. That is two to three times the number of deaths previously predicted.
Currently, the cleanest cities in the country generally measure 7 micrograms of PM2.5 per cubic meters of air in the atmosphere.
At that level, there would still be 1,800 to 3,200 deaths a year in the Bay Area; 8,100 to 14,000 in the Los Angeles region, and 2,000 to 3,500 in the San Joaquin Valley.
"The risk in a highly polluted area is similar to living with a smoker," said Bart Croes, the board's chief of research.
The forest fires burning in the Santa Cruz Mountains can cause serious health problems for people breathing in the smoke, he said. The assessments on premature deaths in the study include the effects of California fires in the last few years.
Fine particles - whether from fires or industrial emissions or traffic - penetrate deeply into the lung and inflame the lung tissue. There is evidence that they can cross the tissue into the blood stream, and accumulate in the organs.
Scientists today believe that it's the size that causes the problem. However, research continues to see if materials in the particles such as XXXXls or other toxic compounds may be the ones most responsible for the damage to the body.
Cancer study

Most of the studies used in the re-evaluation were epidemiological studies. Included in the report was an American Cancer Society study of 300,000 people in cities nationwide. Over 18 years, the cancer society looked at people who lived in cities that had low levels of small particulate matter and compared them to people who lived in cities with higher levels.
Researchers looked at diet, smoking habits and other factors in trying to isolate the pollution effects, which Croes noted was a difficult task.
As part of the assessment, they looked at changes in death rates during a coal-burning ban in Dublin, Ireland, sulfur dioxide reduction under new regulations in Hong Kong and a steel mill strike in Utah Valley.
Representatives of the Western States Petroleum Association said they hadn't yet evaluated the draft of the study. The California Truckers Association, which is expected to comment, didn't respond to queries from The Chronicle.
The air board will accept comments until July 11. The study could be accepted by the board as early as August
er higher than earlier esti

ولـــود
30-10-2009, 04:53 PM
مشكوووووره