WHAT IS MEANT BY AIR POLLUTION?

Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or damages the natural environment, into the atmosphere.

The atmosphere is a complex, dynamic natural gaseous system that is essential to support life on planet Earth. Stratospheric ozone depletion due to air pollution has long been recognized as a threat to human health as well as to the Earth's ecosystems
SOURCEhttp://images.google.co.in/images?hl=en&um=1&q=PHOTOS+OF+AIRPOLLUTION&sa=N&start=40&ndsp=20

ABOUT AIR POLLUTANTS

An air pollutant is known as a substance in the air that can cause harm to humans and the environment. Pollutants can be in the form of solid particles, liquid droplets, or gases. In addition, they may be natural or man-made.[1]

Pollutants can be classified as either primary or secondary. Usually, primary pollutants are substances directly emitted from a process, such as ash from a volcanic eruption, the carbon monoxide gas from a motor vehicle exhaust or sulfur dioxide released from factories.

Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact. An important example of a secondary pollutant is ground level ozone - one of the many secondary pollutants that make up photochemical smog.

Note that some pollutants may be both primary and secondary: that is, they are both emitted directly and formed from other primary pollutants.

About 4 percent of deaths in the United States can be attributed to air pollution, according to the Environmental Science Engineering Program at the Harvard School of Public Health.

Major primary pollutants produced by human activity include:

Sulfur oxides (SOx) - especially sulfur dioxide, a chemical compound with the formula SO2. SO2 is produced by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide. Further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms H2SO4, and thus acid rain.[2] This is one of the causes for concern over the environmental impact of the use of these fuels as power sources.
Nitrogen oxides (NOx) - especially nitrogen dioxide are emitted from high temperature combustion. Can be seen as the brown haze dome above or plume downwind of cities.Nitrogen dioxide is the chemical compound with the formula NO2. It is one of the several nitrogen oxides. This reddish-brown toxic gas has a characteristic sharp, biting odor. NO2 is one of the most prominent air pollutants.
Carbon monoxide - is a colourless, odourless, non-irritating but very poisonous gas. It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide.
Carbon dioxide (CO2) - a greenhouse gas emitted from combustion but is also a gas vital to living organisms. It is a natural gas in the atmosphere.
Volatile organic compounds - VOCs are an important outdoor air pollutant. In this field they are often divided into the separate categories of methane (CH4) and non-methane (NMVOCs). Methane is an extremely efficient greenhouse gas which contributes to enhanced global warming. Other hydrocarbon VOCs are also significant greenhouse gases via their role in creating ozone and in prolonging the life of methane in the atmosphere, although the effect varies depending on local air quality. Within the NMVOCs, the aromatic compounds benzene, toluene and xylene are suspected carcinogens and may lead to leukemia through prolonged exposure. 1,3-butadiene is another dangerous compound which is often associated with industrial uses.
Particulate matter - Particulates, alternatively referred to as particulate matter (PM) or fine particles, are tiny particles of solid or liquid suspended in a gas. In contrast, aerosol refers to particles and the gas together. Sources of particulate matter can be man made or natural. Some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and various industrial processes also generate significant amounts of aerosols. Averaged over the globe, anthropogenic aerosols—those made by human activities—currently account for about 10 percent of the total amount of aerosols in our atmosphere. Increased levels of fine particles in the air are linked to health hazards such as heart disease, altered lung function and lung cancer.
Toxic metals, such as lead, cadmium and copper.
SOURCEhttp://en.wikipedia.org/wiki/Air_pollution

SOURCES OF AIR POLLUTANTS

Sources of air pollution refer to the various locations, activities or factors which are responsible for the releasing of pollutants in the atmosphere. These sources can be classified into two major categories which are:

Anthropogenic sources (human activity) mostly related to burning different kinds of fuel

"Stationary Sources" include smoke stacks of power plants, manufacturing facilities (factories) and waste incinerators, as well as furnaces and other types of fuel-burning heating devices
"Mobile Sources" include motor vehicles, marine vessels, aircraft and the effect of sound etc.
Chemicals, dust and controlled burn practices in agriculture and forestry management. Controlled or prescribed burning is a technique sometimes used in forest management, farming, prairie restoration or greenhouse gas abatement. Fire is a natural part of both forest and grassland ecology and controlled fire can be a tool for foresters. Controlled burning stimulates the germination of some desirable forest trees, thus renewing the forest.
Fumes from paint, hair spray, varnish, aerosol sprays and other solvents
Waste deposition in landfills, which generate methane.Methane is not toxic; however, it is highly flammable and may form explosive mixtures with air. Methane is also an asphyxiant and may displace oxygen in an enclosed space. Asphyxia or suffocation may result if the oxygen concentration is reduced to below 19.5% by displacement
Military, such as nuclear weapons, toxic gases, germ warfare and rocketry
Natural sources

Dust from natural sources, usually large areas of land with little or no vegetation.
Methane, emitted by the digestion of food by animals, for example cattle.
Radon gas from radioactive decay within the Earth's crust.Radon is a colorless, odorless, naturally occurring, radioactive noble gas that is formed from the decay of radium. It is considered to be a health hazard.Radon gas from natural sources can accumulate in buildings, especially in confined areas such as the basement and it is the second most frequent cause of lung cancer, after cigarette smoking.
Smoke and carbon monoxide from wildfires.
Volcanic activity, which produce sulfur, chlorine, and ash
SOURCEhttp://en.wikipedia.org/wiki/Air_pollution

WHAT ARE THE CAUSES OF AIR POLLUTION???

Air pollution is something that we cannot really ignore now-a-days. This is evident from the moment we step out of our house and are greeted with black colored smog that hits us directly reminding us that breathing clean air is more of a distant dream. It is so easy for us to endlessly rant and rave about the causes of air pollution and its ill effects, but little do we realize that each person is responsible for all the causes of air pollution and the situation that we face today. Take a look around you at the dismal state of affairs. The thick smog that is seen in the morning hours is not really due to somebody else but rather due to each and every one of us. Here is a look at the causes of air pollution and how it can affect us if the matter is not taken care of at this stage itself.

Causes of Air Pollution:
Carbon dioxide is one the main pollutants that causes air pollution. This is because, although living beings do exhale carbon dioxide, this gas is harmful when emitted from other sources, which are caused due to human activity. An additional release of carbon dioxide happens due to various such activities. Carbon dioxide gas is used in various industries such as the oil industry and the chemical industry. The manufacturing process of most products would require the use of this gas. There are various human activities that add to the increased proportions of carbon dioxide in the atmosphere. The combustion of fossil fuels and the harmful effects of deforestation have all contributed towards the same. show that amongst the various gasses emitted during a volcanic eruption, carbon dioxide remains to be at least 40% of the emission. Scientists have now therefore identified carbon dioxide as one of those elements that have contributed to global warming.

Causes of air pollution are not limited to this. The combustion of fuels in automobiles, jet planes etc all cause the release of several primary pollutants into the air. The burning of fossil fuels in big cities which is seen at most factories, offices and even a large number of homes, it is no wonder that air pollution is increasing at an alarming rate. The release of other harmful gases all adds to the state that we see today. Although carbon dioxide plays an important role in various other processes like photosynthesis, breathing an excess of the same also causes harmful effects towards one’s health.

The various causes of air pollution that releases harmful gases into the atmosphere are caused due to the increasing number of power plants and manufacturing units or industries that mostly have activities related to the burning of fuels. Besides, as mentioned earlier, most automobiles, marine vessels, activities that involve the burning of wood, fumes that are released from aerosol sprays, military activities that involve the use of nuclear weapons, all are the numerous causes of air pollution.

Carbon monoxide is another such gas which, although was present in the atmosphere earlier, is now considered to be a major pollutant. An excess of the same has a harmful effect on our system. There are many reasons why carbon monoxide can be released into the atmosphere as a result of human activities. This is also produced due to any fuel burning appliance and appliances such as gas water heaters, fireplaces, woodstoves, gas stoves, gas dryers, yard equipments as well as automobiles, which add to the increased proportion of this gas into the atmosphere.

Sulfur dioxide is yet another harmful pollutant that causes air pollution. Sulfur dioxide is emitted largely to the excessive burning of fossil fuels, petroleum refineries, chemical and coal burning power plants etc. Nitrogen dioxide when combined with sulfur dioxide can even cause a harmful reaction in the atmosphere that can cause acid rain.

Nitrogen dioxide is one more gas that is emitted into the atmosphere as a result of various human activities. An excess of nitrogen dioxide mainly happens due to most power plants seen in major cities, the burning of fuels due to various motor vehicles and other such sources, whether industrial or commercial that cause the increase in the levels of nitrogen dioxide.

These and a number of other hazardous air pollutants are emitted with the various numbers of activities that we carry out during the day which are the main causes of air pollution.

How you can help to prevent Air Pollution:Carpool- This will help to reduce the number of vehicles on the already congested roads.
Always keep your car tuned properly so that it remains in a good condition.
Save energy- Try to use minimum amounts of natural gas and even electricity. Whenever possible, avoid the use of air conditioner and use a fan instead.
Always buy recycled products.
Reuse things such as paper and plastic bags, paper etc. This will contribute a lot towards reducing the effects of air pollution and global warming.
Avoid the use of firecrackers. You don’t really need it to express your feeling of happiness.
Go in for water-based paints instead of varnishes.
If you really cannot avoid using your car, plan your work systematically to reduce air pollution.
The causes of air pollution can be many to name if one really scrutinizes this subject closely. With a little effort from our side, we can help to reduce the harmful effects of air pollution so that we can breathe in a clean and healthy environment

How can air pollution hurt my health?

Air pollution can affect our health in many ways with both short-term and long-term effects. Different groups of individuals are affected by air pollution in different ways. Some individuals are much more sensitive to pollutants than are others. Young children and elderly people often suffer more from the effects of air pollution. People with health problems such as asthma, heart and lung disease may also suffer more when the air is polluted. The extent to which an individual is harmed by air pollution usually depends on the total exposure to the damaging chemicals, i.e., the duration of exposure and the concentration of the chemicals must be taken into account.

Examples of short-term effects include irritation to the eyes, nose and throat, and upper respiratory infections such as bronchitis and pneumonia. Other symptoms can include headaches, nausea, and allergic reactions. Short-term air pollution can aggravate the medical conditions of individuals with asthma and emphysema. In the great "Smog Disaster" in London in 1952, four thousand people died in a few days due to the high concentrations of pollution.

Long-term health effects can include chronic respiratory disease, lung cancer, heart disease, and even damage to the brain, nerves, liver, or kidneys. Continual exposure to air pollution affects the lungs of growing children and may aggravate or complicate medical conditions in the elderly. It is estimated that half a million people die prematurely every year in the United States as a result of smoking cigarettes.

Research into the health effects of air pollution is ongoing. Medical conditions arising from air pollution can be very expensive. Healthcare costs, lost productivity in the workplace, and human welfare impacts cost billions of dollars each year.

Additional information on the health effects of air pollution is available from the Natural Resources Defense Council. A short article on the health effects of ozone (a major component of smog) is available from the B.A.A.Q.M.D.
SOURCEhttp://www.lbl.gov/Education/ELSI/Frames/pollution-health-effects-f.html

Air pollution causes dangerous blood clots

THE latest in a growing list of health problems linked to air pollution: dangerous blood clots triggered by smog from traffic and factories.

If a deep vein thrombosis (DVT) breaks loose from where it forms in the lower leg or thigh and travels to the lungs, it can cause breathing problems and sometimes death. Andrea Baccarelli and colleagues at Harvard School of Public Health monitored the air quality in different parts of the Lombardy region of Italy. They also collected the home addresses of 870 people from the region diagnosed with DVT between 1995 and 2005, and 1200 healthy controls. When they controlled for socio-economic factors, they found that living in an area with 25 per cent more particulate pollution than the average for big European cities increases the risk of DVT by 70 per cent compared with the average for the whole population (Archives of Internal Medicine, vol 168, p 920
SOURCEhttp://www.newscientist.com/article/mg19826563.800-air-pollution-causes-dangerous-blood-clots.html

What is Acid Rain and What Causes It?

"Acid rain" is a broad term used to describe several ways that acids fall out of the atmosphere. A more precise term is acid deposition, which has two parts: wet and dry.

Wet deposition refers to acidic rain, fog, and snow. As this acidic water flows over and through the ground, it affects a variety of plants and animals. The strength of the effects depend on many factors, including how acidic the water is, the chemistry and buffering capacity of the soils involved, and the types of fish, trees, and other living things that rely on the water.

Dry deposition refers to acidic gases and particles. About half of the acidity in the atmosphere falls back to earth through dry deposition. The wind blows these acidic particles and gases onto buildings, cars, homes, and trees. Dry deposited gases and particles can also be washed from trees and other surfaces by rainstorms. When that happens, the runoff water adds those acids to the acid rain, making the combination more acidic than the falling rain alone.

Prevailing winds blow the compounds that cause both wet and dry acid deposition across state and national borders, and sometimes over hundreds of miles. Scientists discovered, and have confirmed, that sulfur dioxide (SO2) and nitrogen oxides (NOx) are the primary causes of acid rain. In the US, About 2/3 of all SO2 and 1/4 of all NOx comes from electric power generation that relies on burning fossil fuels like coal.
SOURCEhttp://www.policyalmanac.org/environment/archive/acid_rain.shtml