AIR POLLUTION
• Natural Sources of Air Pollution
NAME : MAIZATUL AKMAL AHMAD KAMARRUDIN
MATRIC NO : D20061026288
PROGRAM : SCIENCE (AT 16)
NO TEL : 017-6176164
GROUP : H
LECTURER’S : Ass. Prof Dr Nur Tjahjadi
1.0 INTRODUCTION
The definition of air pollution by Dewan Bahasa dan Pustaka dictionary is the air defilement by gas waste smoke physically or chemically. Normally, air pollution is the human introduction into the atmosphere of chemicals, particulate matter, or biological materials. These effects will cause harm or discomfort to humans besides to other living organisms and can damages the environment. It does also can cause deaths and respiratory disease that in fact dangerous for human. Air pollution is often identifying with major stationary sources, but the greatest source of emissions is mobile sources, mainly automobiles.
In additions, air pollution is the action of environmental contamination with man-made waste into the air. The air we breathe is composed of a mixture of gases: 78% nitrogen, 21% oxygen, and a small percentage of other gases like argon, carbon dioxide, and water vapour. The Earth's air also contains pollutants or harmful material we may also breathe. Some of these air pollutants may be odourless and colourless. Other air pollution may be so apparent that it surrounds us like smog, which is a cloud or haze of air pollution.
Gases such as carbon dioxide, which also can contribute to global warming that can cause greenhouse effect, have recently gained recognition as pollutants by climate scientists. Many times factories release greenhouse gases like carbon dioxide, chlorofluorocarbons (CFCs), methane, and nitrous oxide into the atmosphere. These greenhouse gases trap heat within the atmoshpere, thus raising the temperture of the Earth. There are also other harmful gases that released when fossil fuels are burned. These gases have significant negative health and environmental effects. The following gases that are known as the "Big Six" air pollutants are Carbon Dioxide, Carbon Monoxide, Sulfur Oxide, Nitrogen Oxide, Hydrocarbons, and Particulates.
Air pollution is the part of the daily existence of the many thousands of people who work, live and use the streets in many cities. The poor and socially marginalized in particular tend to suffer strangely from the effects of deteriorating air quality. Despite improvement in many Asian cities, air pollution is still relatively high compare to cities developed world. Particulate matter, nitrogen dioxide, and ozone are the key pollutants that still cause a significant challenge to improving urban air quality.
According to the Environmental Protection Agency (EPA), Americans release some 147 million metric tons of air pollution in each year. While, worldwide emissions of these pollutants are around 2 billion metric tons per year. The EPA estimates that, since 1990, when regulation of the most hazardous materials began, air toxics emissions have been reduced more than 1 million tons per year. This is almost ten times the reductions achieved in the previous 20 years. Since the 1970s, the levels of major pollutants monitored by the EPA have decrease in the
As the pictures below, air pollution is a global crisis. It is not an isolated occurance, but affects every person on Earth. We must become more conscientious and aware that we should take care the pollution so that people will live in the good conditions.
2.0 NATURAL SOURCES OF AIR POLLUTION
As the wealth of a city increases so do the key driving forces. These are mainly road transport, power and heat production, industry, and agriculture. In some countries such as
Once released into the atmosphere, air pollutants undergo chemical reactions resulting in a wide variation in pollutant concentrations with time and location and corresponding exposure of the population. Most conventional pollutants are produce primarily from burning fossil fuels, especially in coal-powered electric plants and in cars and trucks, as well as in processing natural gas and oil. Others especially sulphur and metals are by products of mining and manufacturing processes. Of the 188 air toxics listed in the Clean Air Act, about two-thirds are volatile organic compounds (VOCs), and most of the rest are metal compounds.
Pollutants can classify as two types that are primary or secondary. Primary pollution are substances directly emitted from a process, such as dust from a volcanic eruption, the carbon monoxide gas from a motor vehicle exhaust or sulphur dioxide released from factories. While secondary pollutant produces through reactions between primary pollutants and normal atmospheric compounds such as reaction from sunlight with ozone.
We can say that, the main primary pollutants produced by human activity such as :
I.
It’s a colourless, corrosive gas with a penetrating odour that irritates the eyes and air passages. Once in the atmosphere, it can be further oxidize to sulphur trioxide (SO3), which reacts with water vapour or dissolves in water droplets to form sulphuric acid (H2SO4), which is a major component of acid rain.
The most common sources of sulphur dioxide include fossil fuel combustion, smelting, manufacture of sulphuric acid, conversion of wood pulp to paper, burning of refuse and production of elemental sulphur. Coal burning is the single largest man-made source of sulphur dioxide accounting for about 50% of annual global emissions, with oil burning accounting for a further 25-30%. The most common natural source of sulphur dioxide is volcanoes.
In addition, the effects of sulphur dioxide for human can caused breathing problem, coughing or sore throat and, may cause permanent pulmonary damage. When mix with water and contacted by skin, frostbite may occur. When it makes contact with eyes, redness and pain will occur.
The most common natural source of sulphur dioxide is volcanoes.
II. Nitrogen Oxides (NOx)
Nitrogen oxides are highly reactive gases formed when combustion especially combustion at high temperatures initiates reactions between atmospheric nitrogen and oxygen. At ambient temperatures, the oxygen and nitrogen gases in air will not react with each other. In an internal combustion engine, combustion of a mixture of air and fuel will produces combustion temperatures high enough to drive endothermic reactions between atmospheric nitrogen and oxygen in the flame, yielding various oxides of nitrogen. In areas of high motor vehicle traffic, such as in large cities, the amount of nitrogen oxides emitted into the atmosphere can be quite significant.
The initial product, nitric oxide (NO), oxidizes further in the atmosphere. Once it is mixed with air, it’s quickly combines with oxygen, forming nitrogen dioxide (NO2). It is also present in tobacco smoke. It is a reddish brown, nonflammable, gas with a detectable smell. In significant concentrations it is highly toxic, causing serious lung damage with a delayed effect. Other health effects of exposure to nitrogen dioxide include shortness of breath and chest pains. Nitrogen dioxide is a strong oxidizing agent that reacts in the air to form corrosive nitric acid, as well as toxic organic nitrates. It also plays a major role in the atmospheric reactions that produce ground-level ozone or smog.
In addition, nitrogen oxides can combine with water to form nitric acid, which is also a major component of acid precipitation. Excess nitrogen in water is causing eutrophication of inland waters and coastal seas. It may also encourage the growth of weedy species that crowd out native plants. ( Text : ‘Principles of Environmental Science, 2008, by William P. Cunningham, pages 218 ).
This pictures above are present the sources of Nitrogen Oxide gases that can caused shortness of breath, chest pains and others.
III. Carbon Monoxide (CO)
Carbon monoxide is colourless, odourless, non-irritating but very poisonous gas. It is a product by incomplete combustion of fuel such as natural gas, coal, oil, charcoal or wood. Carbon monoxide forms in preference to the more usual carbon dioxide when there is a reduced availability of oxygen present during the combustion process.
Vehicular exhaust is a major source of carbon monoxide. Land-clearing fires and cooking fires also are major sources of carbon monoxide. About 90 percent of the CO in the air is consuming in photochemical reactions that produce ozone. ( Text : ‘Principles of Environmental Science, 2008, by William P. Cunningham, pages 219 ).
Carbon monoxide is poisonous when inhaled because it combines with haemoglobin, the oxygen-carrying substance in red blood cells. The haemoglobin then cannot take up oxygen from the air. Lack of oxygen causes cells and tissues to die.
Vehicular smoke, cooking fires, and land-clearing fires are major sources of carbon monoxide
IV. Particulate Material
Particulate matter is a complex mixture of organic and inorganic substances, present in the atmosphere as both liquids and solids. Particulate matters such as dust, ash, soot, lint, smoke, pollen, spores, algal cells, and many other suspended materials are the example of the coarse particles that can be regarded as those with a diameter greater than 2.5 micrometres (µm). Aerosols, combustion particles, extremely minute particles, or liquid droplets suspended in the air, are the example of fine particles that is less than 2.5 micrometer.
Particulates often are the most apparent from of air pollution. This is because, they reduce visibility and leave dirty deposits on windows, painted surfaces, and textiles. Breathable particles smaller than 2.5µm are among the most dangerous for humans health. This is because they can damage lung tissues. Asbestos fibbers and cigarette smokes and among the most dangerous respirable particles in urban and indoor air because they are carcinogenic.
Some examples of particulate matter which are pollens and algal cell that have diameter greater that 2.5 micrometres.
V. Volatile Organic Compound (VOCs)
. Volatile Organic Compounds or VOCs are organic chemicals that easily vaporize at room temperature. They are called organic because they contain the element carbon in their molecular structures. VOCs have no colour, smell, or taste. Plants, bogs, and terminates are the largest sources of VOCs, especially that can produce natural gas such as isoprene (C5H6), terpenes (C10H15), butane(C4H10), and methane (CH4). All of these gases are the types of hydrocarbon. These volatile hydrocarbons are generally oxides to CO and CO2 in the atmosphere.
Other dangerous synthetic organic chemicals, such as benzene, toluene, formaldehyde, vinly chloride, phenols, chloroform, and trichloroethylene are released by human activities. Principal sources are incompletely burned fuels from vehicles, power plants, chemical plants, and petroleum refineries. These chemicals play an important role in the formation of photochemical oxidants.
Photochemical oxidants are products of secondary atmospheric reactions driven by solar energy. One of the most important of these reactions involves formation of singlet (atomic) oxygen by splitting nitrogen dioxide (NO2). This atomic oxygen then reacts with another molecule to O2 to make ozone O3. Although ozone is important in the stratosphere, in ambient air it highly reactive and damages vegetation, animal tissues, and building materials. Ozone’s acrid, biting odor is a distinctive characteristic of photochemical smog.
Some examples of power plants.
VI. Lead
Lead is widespread neurotoxins that can damage the nervous system. By some estimate, 20% of all inner city children suffer some degree of development retardation from high environmental lead levels. Long-range transport of lead through the air is causing bioaccumulation in remote aquatic ecosystem, such as arctic lakes and seas.
Anthropogenic sources of six of the primary ‘criteria’ air pollutants in
INDOOR AIR POLLUTION
OUTDOOR AIR POLLUTANT
PRIMARY POLLUTANT SECONDARY POLLUTANT
3.0 CONCLUSION
Every day, the average person inhales about 20,000 liters of air. Every time we breathe, we risk inhaling dangerous chemicals that have found their way into the air. As we already know, air pollution includes all contaminants that can be found in the atmosphere. These dangerous substances can be either in the form of gases or particles. In addition, air pollution can be found both outdoor and indoor. Pollutants can be trapped inside buildings, causing indoor pollution that lasts for a long time.
The sources of air pollution are both come from natural and human-based. As one might expect, humans have been producing increasing amounts of pollution as time has progressed, and they now account for the majority of pollutants released into the air. This will cause serious consequences for the health of human beings and severely affects natural ecosystems.
Air pollution is able to travel easily because it is located in the atmosphere. As a result, air pollution is a global problem and has been the subject of global cooperation and conflict. Some areas now suffer more than others do from air pollution. Cities with large numbers of automobiles or those that use great quantities of coal often suffer most severely from problems of air pollution.
Air pollution has many disastrous effects that need to be curbed. In order to accomplish this, governments, scientists and environmentalists are using or testing a variety of methods aimed at reducing pollution. In the
4.0 BIBLIOGRAPHY
Dieter Schwela et al. (2006). Urban Air Pollution In Asian Cities – Status, Challenges And Managment.
William P. Cunningham and Mary Ann Cunningham. (2008). Principles Of Environmental Science.
http://library.thinkquest.org/26026/Environmental_Problems/air_pollution.html
http://www.ace.mmu.ac.uk/eae/air_quality/Older/Natural_Air_Pollution.html
http://www.doe.gov.my/en/content/sources-air-pollution
http://www.pages.drexel.edu/~cy34/#airpollution
http://en.wikipedia.org/wiki/Air_pollution
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