Saturday, 6 July 2013

PLASTIC POLLUTION

                              PLASTIC POLLUTION

 





Plastic products have become an integral part in our daily life as a basic need. It produced on a massive scale worldwide and its production crosses the 150 million tonnes per year globally. In India approximately 8 Million tonnes plastic products are consumed every year (2008). Its broad range of application in films, wrapping materials, shopping and garbage bags, fluid containers, clothing, toys, household and industrial products, and building materials. It is a fact that plastics will never degrade and remains on landscape for several years. Mostly, plastics are recyclable but recycled products are more hazardous to the environment than the virgin products. The recycling of a virgin plastic material can be done 2-3 time only, because after every recycling, the plastic material is deteriorated due to thermal pressure. Considering, 70% of plastic consumption is converted as waste, approximately 5.6 million tons per annum (TPA) plastic waste is generated in country, which equals to 15342 tons per day (TPD).




Plastic Waste Management:



(i.) Recycling of plastic wastes will be carried out as per rules and regulations stipulated by the
Central Government.

(ii.) The municipal authority shall be responsible for operationalization and coordination of the
waste management system and for performing the associated functions:
(a.) To ensure safe collection, storage, segregation, transportation, processing and disposal of
plastic waste.
(b.) To ensure that no damage is caused to the environment during this process.
(c.) To ensure setting up of collection centres for plastic waste involving manufacturers.
(d.) To ensure its channelization to recyclers
(e.) To create awareness amongst all stakeholders about their responsibilities
(f.) To engage agencies or groups working in waste management including waste pickers.
(g.) To ensure that open burning of plastic waste is not permitted.



(iii.) For setting up plastic waste collection centres, the municipal authority may ask
manufactures, either collectively or individually in line with the principle of Extended Producer’s
Responsibility (EPR) to provide the required finance to establish such collection centre.
(iv.) The Municipal Authority shall encourage the use of plastic waste by adopting suitable
technology such as in road construction, co‐incineration, etc. The municipal authority or the
operator intending to use such technology shall ensure the compliance with the prescribed
standards including pollution norms prescribed by the competent authority in this regard.
Protocols

Tuesday, 2 July 2013

VOLCANO EFFECT ON ENVIRONMENT

 

          VOLCANO EFFECT ON ENVIRONMENT

 

Volcanoes that have not erupted for some time are dormant, and volcanoes that have not erupted even in the distant past are called extinct. Volcanic activity and volcanic eruption is usually triggered by alterations of tectonic plates, resulting in landslides or earthquakes.

There are different types of volcanic eruptions:

- Phreatic: explosion of steam, water, ash and rock as magma comes in contact with groundwater or surface water
- Rhyolite flow: high-silica lava (>68%)
- Basalt flow: low-silica lava (when the silica content is low, lava usually has a higher magnesium and iron content)
- Pyroclastic flow: fast-moving hot ash, gas and rock
- Lahar: mudflow of pyroclastic material into a river valley
- Carbon dioxide emission


Volcanic eruptions can be extremely damaging to the environment, particularly because of a number of toxic gases possibly present in pyroclastic material. It typically consists mainly of water vapour, but it also contains carbon dioxide and sulphur dioxide gas. Other gases typically found in volcanic ashes are hydrogen sulphide, hydrogen chloride, hydrogen fluoride, carbon monoxide, and volatile metal chlorides.

Carbon dioxide emitted from volcanoes adds to the natural greenhouse effect. Sulphur dioxides cause environmental problems, because they are converted to sulphuric acid in the stratosphere; the main cause of acid rain. Furthermore, sulphate aerosols are formed, which reflect solar radiation and absorb heat, thereby cooling the earth. Sulphate aerosols also take part in chemical reactions, forming ozone destructive material.
An example of a volcanic eruption that caused substantial environmental damage is the Mount Pinatubo eruption in the Philippines.

The eruption of the Eyjafjallajokull volcano is unlikely to have any significant impact on climate but has caused a small fall in carbon emissions, experts say.
Although large eruptions such as Mount Pinatubo in 1991 can spew out enough material to shade and cool the planet, recent activity in Iceland is very small in comparison. The ash cloud has not reached the high atmosphere, where it would have the most effect, and it contains little sulphur, which forms reflective droplets of sulphuric acid. The World Meteorological Organisation in Geneva says any cooling effect from Eyjafjallajokull will be "very insignificant".
A larger effect on the atmosphere, though still small in global terms, comes from the mass-grounding of European flights over the past few days. According to the Environmental Transport Association, by the end of today the flight ban will have prevented the emission of some 2.8m tonnes of carbon dioxide since the first flights were grounded.
The volcanic eruption has released carbon dioxide, but the amount is dwarfed by the savings. Based on readings taken by scientists during the first phase of Eyjafjallajokull activity last month, the website Information is Beautiful calculated the volcano has emitted about 150,000 tonnes of CO2 each day. Worldwide, the US Geological Survey says volcanoes produce about 200m tonnes of carbon dioxide every year.
• This article was changed on 21 April. It originally said the volcano has emitted about 15,000 tonnes of CO2 each day. Information is Beautiful has since corrected this figure to 150,000; we have updated our article to reflect this


How do volcanoes affect people


Volcanoes affect people in many ways, some are good, some are not. Some of the bad ways are that houses, buildings, roads, and fields can get covered with ash. As long as you can get the ash off (especially if it is wet), your house may not collapse, but often the people leave because of the ash and are not around to continually clean off their roofs. If the ashfall is really heavy it can make it impossible to breathe
Lava flows are almost always too slow to run over people, but they can certainly run over houses, roads, and any other structures.
Pyroclastic flows are mixtures of hot gas and ash, and they travel very quickly down the slopes of volcanoes. They are so hot and choking that if you are caught in one it will kill you. They are also so fast (100-200 km/hour) that you cannot out-run them. If a volcano that is known for producing pyroclastic flows is looking like it may erupt soon, the best thing is for you to leave before it does.
Some of the good ways that volcanoes affect people include producing spectacular scenery, and producing very rich soils for farming.

Gases

Water vapor, the most common gas released by volcanoes, causes few problems. Sulfur dioxide, carbon dioxide and hydrogen are released in smaller amounts. Carbon monoxide, hydrogen sulfide, and hydrogen fluoride are also released but typically less than 1 percent by volume.Gases pose the greatest hazard close to the vent where concentrations are greatest. Away from the vent the gases quickly become diluted by air. For most people even a brief visit to a vent is not a health hazard. However, it can be dangerous for people with respiratory problems.
The continuous eruption at Kilauea presents some new problems. Long term exposure to volcanic fumes may aggravate existing respiratory problems. It may also cause headaches and fatigue in regularly healthy people. The gases also limit visibility, especially on the leeward side of the island where they become trapped by atmospheric conditions.

A deadly eruption

The 1815 explosive eruption of Tambora volcano in Indonesia and the subsequent caldera collapse produced 9.5 cubic miles (40 cubic kilometers) of ash. The eruption killed 10,000 people. An additional 80,000 people died from crop loss and famine.

 

 

Aircraft

To put it mildly, ash is bad for jet aircraft engines. Apparently the problem is much more severe for modern jet engines which burn hotter than the older ones. Parts of these engines operate at temperatures that are high enough to melt ash that is ingested. Essentially you end up with tiny blobs of lava inside the engine. This is then forced back into other parts where the temperatures are lower and the stuff solidifies. As you can imagine this is pretty bad. One problem that I heard about is that pilots start losing power and apply the throttle, causing the engine to be even hotter and melt more ash.Added to this is the fact that ash is actually tiny particles of glass plus small mineral shards–pretty abrasive stuff. You can imagine that dumping a whole bunch of abrasive powder into a jet engine is not good for the engine. This has been a pretty non-scientific explanation of the problem. I just found an article that describes the problem a little more technically.
“The ash erodes sharp blades in the compressor, reducing its efficiency. The ash melts in the combustion chamber to form molten glass.

Safe distance

The distance you have to evacuate depends entirely on what kind of eruption is going on. For example, Pinatubo, one of the largest recent eruptions sent pyroclastic flows at least 18 km down its flanks, and pumice falls were hot and heavy even beyond that. For example, pumice 7 cm across fell at Clark Air base which is 25 km from the volcano! A 7 cm pumice won’t necessarily kill you but it does mean that there is a lot of pumice falling, and if you don’t get out and continuously sweep off your roof it may fall in and you’ll get squashed.On the other hand, the current eruption at Ruapehu is relatively small. In fact, there were skiers up on the slopes when the eruptions commenced, and even though they were only 1-2 km from the vent they managed to escape. The volcanologists routinely go up on the higher slopes of Ruapehu during these ongoing eruptions to collect ash and take photographs.
So you see, you need to know something about what you think the volcano is going to do before you decide how far to run away. I guess if you have no idea of what the volcano is planning, and have no idea of what it has done in the past, you might want to be at least 25-30 km away, make sure you have a good escape route to get even farther away if necessary, and by all means stay out of low-lying areas!

Cities and Towns

The effect an eruption will have on a nearby city could vary from none at all to catastrophic. For example, atmospheric conditions might carry ash away from the city or topography might direct lahars and pyroclastic flows to unpopulated areas. In contrast, under certain atmospheric, eruption and/or topographic conditions, lahars, pyroclastic flows, and/or ash fall could enter the city causing death and destruction.
This scenario brings up several interesting problems. How do you evacuate a large population if there is little warning before the eruption? Where do these people go? If an eruption is highly likely yet hasn’t happened yet how long can people be kept away from their homes and businesses?
I should point out that in most volcanic crises geologists advise local civil defense authorities. The civil defense authorities decide what to do concerning evacuations, etc.
The IAVCEI has a program to promote research on “Decade” Volcanoes. Decade volcanoes are likely to erupt in the near future and are near large population centers. Mount Rainier in Washington and Mauna Loa in Hawaii are two Decade volcanoes in the U.S. Other Decade volcanoes include Santa Maria, Stromboli, Pinatubo, and Unzen.
What happens to the towns around a volcano when it erupts depends on many things. It depends of the size and type of eruption and the size and location of the town. A few examples might help. The 1984 eruption of Mauna Loa in Hawaii sent lava towards Hilo but the eruption stopped before the flows reached the town. The 1973 eruption of Heimaey in Iceland buried much of the nearby town of Heimaey under lava and cinder. The 1960 eruption of Kilauea in Hawaii buried all of the nearby town of Kapoho under lava and cinder. In 1980, ash from Mount St. Helens fell on many towns in Washington and Oregon. The 1902 eruption of Mount Pelee on the island of Martinique destroyed the town of Saint Pierre with pyroclastic flows. In 1985, the town of Armero was partially buried by lahars generated on Ruiz. For more examples see Decker and Decker (1989).

Sunday, 30 June 2013

ACID RAIN EFFECT ON ENVIRONMENT

 ACID RAIN EFFECT ON ENVIRONMENT





  "Acid Rain,"  or more precisely acid precipitation, is the word used to describe rainfall that has a pH level of less than 5.6.  This form of air pollution is currently a subject of great controversy because of it's worldwide environmental damages.  For the last ten years, this phenomenon has brought destruction to thousands of lakes and streams in the United States, Canada, and parts of Europe.  Acid rain is formed when oxides of nitrogen and sulfite combine with moisture in the atmosphere to make nitric and sulfuric acids.  These acids can be carried away far from its origin.  This report contains the causes, effects, and solutions to acid rain. 
 
     The two primary sources of acid rain are sulfur dioxide (SO2), and oxides of nitrogen (NOx).  Sulfur dioxide is a colourless, prudent gas released as a by-product of combusted fossil fuels containing sulfur.  A variety of industrial processes, such as the production of iron and steel, utility factories, and crude oil processing produce this gas.  In iron and steel production, the smelting of metal sulfate ore, produces pure metal. This causes the release of sulfur dioxide.  Metals such as zinc, nickel, and copper are commonly obtained by this process.  Sulfur dioxide can also be emitted into the atmosphere by natural disasters or means.  This ten percent of all sulfur dioxide emission comes from volcanoes, sea spray, plankton, and rotting vegetation.  Overall, 69.4 percent of sulfur dioxide is produced by industrial combustion.  Only 3.7 percent is caused by transportation 
     The other chemical that is also chiefly responsible for the make-up of acid rain is nitrogen oxide.  Oxides of nitrogen is a term used to describe any compound of nitrogen with any amount of oxygen atoms.  Nitrogen monoxide and nitrogen dioxide are all oxides of nitrogen.  These gases are by-products of firing processes of extreme high temperatures (automobiles, utility plants), and in chemical industries (fertilizer production).  Natural processes such as bacterial action in soil, forest fires, volcanic action, and lightning make up five percent of nitrogen oxide emission.  Transportation makes up 43 percent, and 32 percent belongs to industrial combustion.  ["Acid Rain."  The New World Book Encyclopedia.  1993.] 

     Nitrogen oxide is a dangerous gas by itself.  This gas attacks the membranes of the respiratory organs and increases the likelihood of respiratory illness.  It also contributes to ozone damage, and forms smog.  Nitrogen oxide can spread far from the location it was originated by acid rain.
     As mentioned before, any precipitation with a pH level less than 5.6 is considered to be acid rainfall.  The difference between regular precipitation and acid precipitation is the pH level.  pH is a symbol indicating how acidic or basic a solution is in ratios of relative concentration of hydrogen ions in a solution.  A pH scale is used to determine if a specific solution is acidic or basic.  Any number below seven is considered to be acidic.  Any number above seven is considered to be basic.  The scale is color coordinated with the pH level.  Most pH scales use a range from zero to fourteen.  Seven is the neutral point (pure water).  A pH from 6.5 to 8, is considered the safe zone.  Between these numbers, organisms are in very little or no harm. 

     Not only does the acidity of acid precipitation depend on emission levels, but also on the chemical mixtures in which sulfur dioxide and nitrogen oxides interact in the atmosphere.  Sulfur dioxide and nitrogen oxides go through several complex steps of chemical reactions before they become the acids found in acid rain.  The steps are broken down into two phases, gas phase and aqueous phase.  There are various potential reactions that can contribute to the oxidation of sulfur dioxide in the atmosphere each having varying degrees of success.  One possibility is photooxidation of sulfuric dioxide by means of ultraviolet light.  This process uses light form the of electromagnetic spectrum.  This causes the loss of by two oxygen atoms.  This reaction was found to be an insignificant contributor to the formation of sulfuric acid.  A second and more common process is when sulfur dioxide reacts with moisture found in the atmosphere.  When this happens, sulfate dioxide immediately oxidizes to form a sulfite ion.
 

SO2 (g)+O2(g) -> SO3(g) 

Afterwards, it becomes sulfuric acid when it joins with hydrogen atoms in the air. 

SO3(g)+H2O(l) -> H2SO4(aq)
 

     This reaction occurs quickly, therefore the formation of sulfur dioxide in the atmosphere is assumed to lead this type of oxidation to become sulfuric acid.  Reaction example 1 (photo Koxidation), is slow due to the absence of a catalyst, proving why it is not a significant contributor.
     Another common reaction for sulfur dioxide to becomes sulfuric acid is by oxidation by ozone.  This reaction occurs at a preferable rate and is sometimes the main contributor to the oxidation of sulfuric acid.  This, hydroxy radical is produced by the photodecomposition of the ozone and is very highly reactive with any species (type of chemical compounds).  It does not require a catalyst and it is approximately 108-109 times more abundant in the atmosphere than molecular oxygen.  Other insignificant reactions include oxidation by product of alkene-zone reactions, oxidation by reaction of NxOy species, oxidation by reactive oxygen transients, and oxidation by peroxy radicals.  These reactions unfortunately prove to be insignificant for various reasons.  All the reactions mentioned so far, are gas phase reactions.  In  the aqueous phase, sulfur dioxide exists as three species:
 

[S(IV)] -> [SO2(aq)] + [HSO32-] + [SO32-] 

This dissociation occurs in a two part process: 

SO2(aq) -> H+ + HSO3 -
HSO3-   (aq) -> H+  + SO32-
 

     The oxidation process of aqueous sulfur dioxide by molecular oxygen relies on metal catalyst such as iron and manganese.  This reaction is unlike other oxidation process, which occurs by hydrogen peroxide.  It requires an additional formation of an intermediate (A-), for example peroxymonosulfurous acid ion.  This formation is shown below. 

HSO3  H2O2 -> A-  +H2O
A-  +H  -> H2SO4 

     Sulfur dioxide oxidation is most common in clouds and especially in heavily polluted air where compounds such as ammonia and ozone are in abundance.  These catalysts help convert more sulfur dioxide into sulfuric acid.   But not all of the sulfur dioxide is converted to sulfuric acid.  In fact, a substantial amount can float up into the atmosphere, transport to another area and return to earth unconverted. 

     Like sulfur dioxide, nitrogen oxides rise into the atmosphere and are oxidized in clouds to form nitric or nitrous acid.  These reactions are catalyzed in heavily polluted clouds where traces of iron, manganese, ammonia, and hydrogen peroxide are present.  Nitrogen oxides rise into the atmosphere mainly from automobile exhaust.  In the atmosphere it reacts with water to form nitric or nitrous acid.
 

NO2(g) + H2O(l) -> HNO3(aq)+HNO2(aq)  [gas phase] 

In the aqueous phase there are three equilibria to keep in mind for the oxidation of nitrogen oxide. 

1.)  2NO2(g) + H2O(l) -> 2H+ + NO3 -  + NO2 -
2.)  NO(g) + NO2(g) + H2O(l) -> 2H+  + 2NO2 -

3.)  3NO2(g) + H2O(l) -> 2H+  + 2NO3 -  + NO(g)
 

     These reactions are limited by the partial pressures of nitrogen oxides present in the atmosphere, and the low solubility of nitrogen oxides, increase in reaction rate occurs only with the use of a metal catalyst, similar to those used in the aqueous oxidation of sulfur dioxide.

     Over the years, scientists have noticed that some forests have been growing more and more slowly without reason.  Trees do not grow as fast as they did before.  Leaves and pines needles turn brown and fall off when they are supposed to be green. 

     Eventually, after several years of collecting and recording information on the chemistry and biology of the forest, researchers have concluded that this was the work of acid rain.  A rainstorm occurs in a forest.  The summer spring washes the leaves of the branches and fall to the forest floor below.  Some of the water is absorbed into the soil.  Water run-off enters nearby streams, rivers, or lakes.  That soil may have neutralized some or all of the acidity of the acid rainwater.  This ability of neutralization is call buffering capacity.  Without buffering capacity, soil pH would change rapidly.  Midwestern states like Nebraska and Indiana have soil that is well buffered.  Nonetheless, mountainous northwest areas such as the Adirondack mountains are less able to buffer acid.  High pH levels in the soil help accelerate soil weathering and remove nutrients.  It also makes some toxic elements, for example aluminum, more soluble.  High aluminum concentrations in soil can prevent the use of nutrients by plants.  Acid rain does not kill trees immediately or directly.  Instead, it is more likely to weaken the tree by destroying its leaves, thus limiting the nutrients available to it.  Or, acid rain can seep into the ground, poisoning the trees with toxic substances that are slowly being absorbed through the roots.  When acid rain falls, the acidic rainwater dissolves the nutrients and helpful minerals from the soil.  These minerals are then washed away before trees and other plants can use them to grow.  Not only does acid rain strip away the nutrients from the plants, they help release toxic substance such as aluminum into the soil.  This occurs because these metals are bound to the soil under normal conditions, but the additional dissolving action of hydrogen ions causes rocks and small bound soil particles to break down.  When acid rain is frequent, leaves tend to lose their protective waxy coating,  When leaves lose their coating, the plant itself is open to any possible disease.  By damaging the leaves, the plant can not produce enough food energy for it to remain healthy.  Once the plant is weak, it can become more vulnerable to disease, insects, and cold weather which may ultimately kill it. 

     Acid rain does not only effect organisms on land, but also effect organisms in aquatic biomes.  Most lakes and streams have a pH level between six and eight.  Some lakes are naturally acidic even without the effects of acid rain.  For example, Little Echo Pond in New York has a pH level of 4.2. 

     There are several routes through which acid rain can enter the lakes.  Some chemical substances exist as dry particles in the atmosphere, while others enter directly into the lake in a form of precipitation.  Acid rain that has fallen on land can be drained through sewage systems leading to lakes.  Another way acids can enter the lake is by spring acid shock.  When acid snow melts in the spring, the acids in the snow seeps into the ground.  Some run-off the ground and into lakes.

     Spring is a vulnerable time for many species since this is the time for reproduction.  The sudden change in pH level is dangerous because the acid can cause serious deformities in their young.  Generally, the young of most species are more sensitive than the elders.  But not all species can tolerate the same amount of acid.  For example, frogs may tolerate relatively high levels of acidity, while snails are more sensitive to pH changes. 

     Sulfuric acid in polluted precipitation interferes with the fish's proficiency to take in oxygen, salt, and nutrients.  For freshwater fish, maintaining osmoregulation (the ability to maintain a state of balance between salt and minerals in the organism's tissue) is essential to stay alive.  Acid molecules cause mucus to form in their gills preventing the fish to absorb oxygen well.  Also, a low pH level will throw off the balance of salt in the fish's tissue.  Calcium levels of some fish cannot be maintained due to the changes in pH level.  This causes a problem in reproduction: the eggs are too brittle or weak.  Lacking calcium causes weak spines and deformities in bones.  Sometimes when acid rainfall runs off the land, it carries fertilizers with it.  Fertilizer helps stimulate the growth of algae because of the amount of nitrogen in it.  However, because of the increase in the death of fish the decomposition takes up even more oxygen.  This takes away from surviving fish.  In other terms, acid rain does not help aquatic ecosystems in anyway.

     Acid rain does not only damage the natural ecosystems, but also man-made materials and structures.  Marble, limestone, and sandstone can easily be dissolved by acid rain.  Metals, paints, textiles, and ceramic can effortlessly be corroded.  Acid rain can downgrade leather and rubber.  Man-made materials slowly deteriorate even when exposed to unpolluted rain, but acid rain helps speed up the process.  Acid rain causes carvings and monuments in stones to lose their features.
 

In limestone, acidic water reacts with calcium to form calcium sulfate.
CaCO3 + H2SO4 -> CaSO4 +  H2CO3
For iron, the acidic water produces an additional proton giving iron a positive charge.
4Fe(s) + 2O2(g) + 8  (aq) -> 4Fe2+  (aq) + 4H2O(l)
When iron reacts with more oxygen it forms iron oxide (rust).
4Fe2+ + (aq) + O2(g) + 4H2O(l) -> 2Fe2O3(s) + 8H+ + (aq)
 

     The repairs on building and monuments can be quite costly.  In Westminster, England, up to ten million pounds was spent necessitated on repairs damaged by acid rain.  In 1990, the United States spent thirty-five billion dollars on paint damage.  In 1985, the Cologne Cathedral cost the Germans approximately twenty million dollars in repairs.  The Roman monuments cost the Romans about two hundred million dollars. 
 
     Most importantly, acid rain can affect health of a human being.  It can harm us through the atmosphere or through the soil from which our food is grown and eaten from.  Acid rain causes toxic metals to break loose from their natural chemical compounds. Toxic metals themselves are dangerous, but if they are combined with other elements, they are harmless.  They release toxic metals that might be absorbed by the drinking water, crops, or animals that human consume.  These foods that are consumed could cause nerve damage to children or severe brain damage or death.  Scientists believe that one metal, aluminum, is suspected to relate to Alzheimer's disease.
     One of the serious side effects of acid rain on human is respiratory problems.  The sulfur dioxide and nitrogen oxide emission gives risk to respiratory problems such as dry coughs, asthma, headaches, eye, nose, and throat irritation.  Polluted rainfall is especially harmful to those who suffer from asthma or those who have a hard time breathing.  But even healthy people can have their lungs damaged by acid air pollutants.  Acid rain can aggravate a person's ability to breathe and may increase disease which could lead to death.
     In 1991, the United States and Canada signed an air quality agreement.  Ever since that time, both countries have taken actions to reduce sulfur dioxide emission.  The United States agree to reduce their annual sulfur dioxide emission by about ten million tons by the year 2000.  A year before the agreement, the Clean Air Pact Amendment tried to reduce nitrogen oxide by two million tons.  This program focused on the source that emits nitrogen oxide, automobiles and coal-fired electric utility boilers.
     Reducing nitrogen oxide emission in a utility plant starts during the combustion phase.  A procedure called Overfire Air is used to redirect a fraction of the total air in the combustion chamber. This requires the combustion process, which is redirected to an upper furnace.  This causes the combustion to occur with less O2 than required, thus slowing down the transformation of atmospheric nitrogen to nitrogen oxide.  After combustion, a system of catalytic reductions are put into effect.  This system embraces the injection of ammonia gas upstream of the catalytic reaction chamber.  The gas will react with nitrogen oxide by this reaction.
 
4NO + 4NH3 + O2 -> 4N2+6H2O

Then it will react with NO2 by the following reaction.
2NO2 + 4NH3 + O2 -> 3N2 + 6H2O
The safe nitrogen can be released into the atmosphere.
     Since most nitrogen oxide emissions are from cars, catalytic converters must be install on cars to reduce this emission.  The catalytic converter is mounted on the exhaust pipe, forcing all the exhaust to pass though it.  This converter looks like a dense honeycomb, but it is coated with either platimun, palladium, or rhodium.  This converts nitrogen oxides, carbon dioxides and unburned hydrocarbons into a cleaner state.
     To reduce sulfur dioxide emission utility plants are required to do several steps  by the Clean Air Act Amendment.  Before combustion, these utilities plants have to go through a process call coal cleaning.  This process is performed gravitationally.  Meaning, it is successful in removing pyritic sulfur due to its high specific gravity, but it is unsuccessful in removing chemically bound organic sulfur.  This cleaning process is only limited by the percent of pyritic sulfur in the coal.  Coal with high amount of pyritic sulfur is coal in higher demands.  Another way to reduce sulfur dioxide before combustion is by burning  coal with low sulfur content.  Low sulfur content coals are called subituminous coal.  This process in reducing sulfur dioxide is very expensive due to the high demand of subituminous coal.
     During combustion, a process called Fluidized Bed Combustion (FBC), is used to reduce sulfur dioxide emissions into the atmosphere. This process contains limestone or a sandstone bed that are crushed and diluted into the fuel. It is important that a balance is established between the heat liberated within the bed from fuel combustion, and the heat removed by the flue gas as it leaves.  Flue gas is the mixture of gases resulting from combustion and other reactions in a chamber.  This enables the limestones to react with sulfur dioxide and reduce emission by 90 percent.  After combustion, a process known as wet flue gas desulfurization is taken into action.  This process requires a web scrubber at the downward end of the boiler.  This process is very similar to FBC.  This scrubber can be made of either limestone or sodium hydroxide.  Limestone is more commonly used.  As sulfur dioxide enters this area it reacts with the limestone in the following example:
 

CaCO3 + SO2 + H2O + O2 -> CaSO3 + CaSO4 + CO2 + H2O
 
After being scrubbed, which is the term used for the phase after coal has past the wet scrubber, the flue gas is re-emmited and the waste solids are disposed.

     Acid rain is an issue that can not be over looked.  This phenomenon destroys anything it touches or interacts with it.  When acid rain damages the forest or the environment it affects humans in the long run.  Once forests are totally destroyed and lakes are totally polluted animals begin to decrease because of lack of food and shelter.  If all the animals, which are our food source, die out, humans too would die out.  Acid rain can also destroy our homes and monuments that humans hold dearly.
     What humans can do, as citizens, to reduce sulfur and nitrogen dioxide emission is to reduce the use of fossil fuels.  Car pools, public transportation, or walking can reduce tons of nitrogen oxide emissions.  Using less energy benefits the environment because the energy used comes from fossil fuels which can lead to acid rain.  For example, turning off lights not being used, and reduce air conditioning and heat usage.  Replacing old appliances and electronics with newer energy efficient products is also an excellent idea.  Sulfur dioxide emission can be reduced by adding scrubbers to utility plants.  An alternative power source can also be used in power plants to reduce emissions.  These alternatives are: geothermal energy, solar power energy, wind energy, and water energy.
     In conclusion, the two primary sources of acid rain is sulfur dioxide and nitrogen oxide.  Automobiles are the main source of nitrogen oxide emissions, and utility factories are the main source for sulfur dioxide emissions.  These gases evaporate into the atmosphere and then oxidized in clouds to form nitric or nitrous acid  and sulfuric acid.  When these acids fall back to the earth they do not cause damage to just the environment but also to human health.  Acid rain kills plant life and destroys life in lakes and ponds.  The pollutants in acid rain causes problem in human respiratory systems.  The pollutants attack humans indirectly through the foods they consumed.  They effected human health directly when humans inhale the pollutants.  Governments have passed laws to reduce emissions of sulfur dioxide and nitrogen oxide, but it is no use unless people start to work together in stopping the release of these pollutants.  If the acid rain destroys our environment, eventually it will destroy us as well.
 

Saturday, 29 June 2013

SMOKING EFFECT ON HUMAN BODY

                  SMOKING EFFECT ON HUMAN BODY 




Nicotine is the addictive drug in tobacco smoke that causes smokers to continue to smoke. Addicted smokers need enough nicotine over a day to ‘feel normal’ – to satisfy cravings or control their mood. How much nicotine a smoker needs determines how much smoke they are likely to inhale, no matter what type of cigarette they smoke.

Along with nicotine, smokers also inhale about 7,000 other chemicals in cigarette smoke. Many of these chemicals come from burning tobacco leaf. Some of these compounds are chemically active and trigger profound and damaging changes in the body.

There are over 60 known cancer-causing chemicals in tobacco smoke. Smoking harms nearly every organ in the body, causing many diseases and reducing health in general.

In Victoria, it is illegal to smoke in cars carrying children under 18 years of age.

Tobacco smoke contains dangerous chemicals


The most damaging compounds in tobacco smoke include:

  • Tar – this is the collective term for all the various particles suspended in tobacco smoke. The particles contain chemicals including several cancer-causing substances. Tar is sticky and brown, and stains teeth, fingernails and lung tissue. Tar contains the carcinogen Benz(a)Pyrenees that is known to trigger tumor development (cancer).
  • Carbon monoxide – this odourless gas is fatal in large doses because it takes the place of oxygen in the blood. Each red blood cell contains a protein called hemoglobin – oxygen molecules are transported around the body by binding to, or hanging onto, this protein. However, carbon monoxide binds to hemoglobin better than oxygen. This means that less oxygen reaches the brain, heart, muscles and other organs.
  • Hydrogen cyanide – the lungs contain tiny hairs (cilia) that help to clean the lungs by moving foreign substances out. Hydrogen cyanide stops this lung clearance system from working properly, which means the poisonous chemicals in tobacco smoke can build up inside the lungs. Other chemicals in smoke that damage the lungs include hydrocarbons, nitrous oxides, organic acids, phenols and oxidizing agents.
  • Free radicals – these highly reactive chemicals can damage the heart muscles and blood vessels. They react with cholesterol, leading to the build-up of fatty material on artery walls. Their actions lead to heart disease, stroke and blood vessel disease.
  • Metals – tobacco smoke contains dangerous metals including arsenic, cadmium and lead. Several of these metals are carcinogenic.
  • Radioactive compounds – tobacco smoke contains radioactive compounds, which are known to be carcinogenic.

Effects of smoking on the respiratory system


The effects of tobacco smoke on the respiratory system include:

  • Irritation of the trachea (windpipe) and larynx (voice box)
  • Reduced lung function and breathlessness due to swelling and narrowing of the lung airways and excess mucus in the lung passages
  • Impairment of the lungs’ clearance system, leading to the build-up of poisonous substances, which results in lung irritation and damage
  • Increased risk of lung infection and symptoms such as coughing and wheezing
  • Permanent damage to the air sacs of the lungs.

Effects of smoking on the circulatory system


The effects of tobacco smoke on the circulatory system include:

  • Raised blood pressure and heart rate
  • Constriction (tightening) of blood vessels in the skin, resulting in a drop in skin temperature
  • Less oxygen carried by the blood
  • Stickier blood, which is more prone to clotting
  • Damage to the lining of the arteries, which is thought to be a contributing factor to atherosclerosis (the build-up of fatty deposits on the artery walls)
  • Reduced blood flow to extremities like fingers and toes
  • Increased risk of stroke and heart attack due to blockages of the blood supply.

Effects of smoking on the immune system


The effects of tobacco smoke on the immune system include:

  • The immune system doesn’t work as well
  • The person is more prone to infections such as pneumonia and influenza
  • Illnesses are more severe and it takes longer to get over them.
  • Lower levels of protective antioxidants (such as Vitamin C), in the blood.

Effects of smoking on the musculus skeletal system


The effects of tobacco smoke on the musculus skeletal system include:

  • Tightening of certain muscles
  • Reduced bone density.

Other effects of smoking on the body


  • Irritation and inflammation of the stomach and intestines
  • Increased risk of painful ulcers along the digestive tract
  • Reduced ability to smell and taste
  • Premature wrinkling of the skin
  • Higher risk of blindness
  • Gum disease (periodontists).

Effects of smoking on the male body


The specific effects of tobacco smoke on the male body include:

  • Lower sperm count
  • Higher percentage of deformed sperm

  • Genetic damage to sperm
  • Impotence, which may be due to the effects of smoking on blood flow and damage to the blood vessels of the penis.

  Effects of smoking on the female body


The specific effects of tobacco smoke on the female body include:

  • Reduced fertility
  • Menstrual cycle irregularities or absence of menstruation
  • Menopause reached one or two years earlier
  • Increased risk of cancer of the cervix
  • Greatly increased risk of stroke and heart attack if the smoker is aged over 35 years and taking the oral contraceptive pill.

Effects of smoking on the unborn baby


The effects of maternal smoking on an unborn baby include:

  • Increased risk of miscarriage, stillbirth and premature birth
  • Low birth weight, which may have a lasting effect of the growth and development of children. Low birth weight is associated with an increased risk for heart disease, stroke, high blood pressure, being overweight and diabetes in adulthood

  • Increased risk of cleft palate and cleft lip
  • Paternal smoking can also harm the fetus if the non-smoking mother is exposed to second-hand smoke.
If the mother or father continues to smoke during their baby’s first year of life, the child has an increased risk of ear infections, respiratory illnesses such as pneumonia and bronchitis, sudden infant death syndrome (SIDS) and meningococcal disease.


Diseases caused by long-term smoking


A lifetime smoker is at high risk of developing a range of potentially lethal diseases, including:

  • Cancer of the lung, mouth, nose, voice box, tongue, nasal sinus, oesophagus, throat, pancreas, bone marrow (myeloid leukaemia), kidney, cervix, ovary, ureter, liver, bladder, bowel and stomach
  • Lung diseases such as chronic obstructive pulmonary disease, which includes chronic bronchitis and emphysema
  • Coronary artery disease, heart disease, heart attack and stroke

  • Ulcers of the digestive system
  • Osteoporosis and hip fracture
  • Poor blood circulation in feet and hands, which can lead to pain and, in severe cases, gangrene and amputation.

Friday, 28 June 2013

GLOBAL WARMING EFFECT ON EARTH

GLOBAL WARM 



Earth's climate is changing. In the past 50 years, the average temperature in the United States has gone up by 2 degrees F, precipitation has increased by roughly 5 percent, and extreme weather events have become more frequent and intense, according to a recent report by the U.S. Global Change Research Program. Global warming doesn't just impact nature; your daily life is affected, too.


Food

Food prices are rising as climate change makes it trickier to maintain the specific conditions crops need to thrive. As the climate warms, the air holds more moisture and rainstorms become more intense, damaging crops. Overall precipitation patterns are also changing, bringing droughts to some areas of the world and floods to others. A recent study published by Stanford University showed that global wheat production decreased by 5.5 percent as a result of an unstable climate, and world corn production was down by nearly 4 percent. So far, North American farmers haven't seen the same drop in productivity, but that is expected to change. (See References 2) The EPA reports that an additional increase of 3.6 degrees F in the global temperature could decrease production of American corn by 10 to 30 percent .


Fresh Water

Fresh water is becoming scarcer in some regions. Many mountainous states rely on snow melt to replenish their water sources, and snowpack is declining as well as melting earlier in the season. Severe droughts, increased evaporation and changes in precipitation patterns are impacting water levels in streams, rivers and lakes. Nearly 18 percent of the world's fresh water is found in the Great Lakes, which supply drinking water to a large region. Scientists expect lake levels to drop as the climate continues to warm up. Lake Superior --- the largest of the five Great Lakes --- is 4.5 degrees F warmer than it was in 1980, and water levels in all of the Great Lakes have generally declined since 1986 .

NATURAL EFFECT ON ENVIRONMENT

Waves give rhythm to the ocean. They transport energy over vast distances. Where they make landfall, waves help to sculpt a unique and dynamic mosaic of coastal habitats. They impart a watery pulse upon
intertidal zones and trim back coastal sand dunes as they creep towards the sea. Where coasts are rocky, waves and tides can, over time, erode the shoreline leaving dramatic sea cliffs Thus, understanding ocean waves is an important part of understanding the coastal habitats they influence. In general, there are three types of ocean waves: wind-driven waves, tidal waves, and tsunamis.
  • Wind-Driven Waves—Wind-driven waves are waves that form as wind passes over the surface of the open water. Energy from the wind is transfered into the topmost layers of water via friction and pressure. These forces develop a disturbance that is transported through the sea water. It should be noted that it is the wave that moves, not the water itself (for the most part). For a demonstration of this principle, see What is a Wave? Additionally, the behavior of waves in water adheres to the same principles that governs the behavior of other waves such as sound waves in air.
  • Tidal Waves—Tidal waves are the largest oceanic waves on our planet. Tidal waves are formed by the gravitational forces of the earth, sun, and moon. The gravitational forces of the sun and (to a greater extent) the moon pull on the oceans causing the oceans to swell on either side of the earth (the side closest to the moon and the side farthest from the moon). As the earth rotates, the tides go 'in' and 'out' (the earth moves but the bulge of water remains in line with the moon, giving the appearance that the tides are moving when it is in fact the earth that is moving).
  • Tsunamis—Tsunamis are large, powerful oceanic waves caused by geological disturbances (earthquakes, landslides, volcanic eruptions) and are normally very large waves.

When Waves Meet

Now that we've defined some types of ocean waves, we'll look at how waves behave when they encounter other waves (this gets tricky so you may want to refer to the sources listed at the end of this article for more information). When ocean waves (or for that matter any waves such as sound waves) meet one another the following principles apply:

  • Superposition—When the waves traveling through the same medium at the same time pass through one another, they do not disturb each other. At any point in space or time, the net displacement that is observed in the medium (in the case of ocean waves, the medium is sea water) is the sum of the individual wave displacements (Source: Russell, 2007).
  • Destructive Interference—Destructive interference occurs when two waves collide and the crest of one wave aligns with the trough of another wave. The result is that the waves cancel each other out.
  • Constructive Interference—Constructive interference occurs when two waves collide and the crest of one wave aligns with the crest of another wave. The result is that the waves add together each other out.

Where Land Meets Sea

When waves meet the shore, they are reflected which means that wave is pushed back or resisted by the shore (or any hard surface) such that the wave motion is sent back in the other direction. Additionally, when waves meet a shore, it is refracted. As the wave approaches the shore it experiences friction as it moves over the sea floor. This frictional force bends (or refracts) the wave differently depending on the characteristics of the sea floor