combustion leading to environmental pollution and ways and means to check pollution
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China's State Environment Protection Agency (SEPA) is responsible for measuring the level of air pollution in China. As of 28 August 2008, SEPA monitors daily pollution level in 86 of its major cities. The API level is based on the level of 5 atmospheric pollutants, namely sulfur dioxide (SO2), nitrogen dioxide (NO2), suspended particulates (PM10), carbon monoxide (CO), and ozone (O3) measured at the monitoring stations throughout each city.
An individual score is assigned to the level of each pollutant and the final API is the highest of those 5 scores. The pollutants can be measured quite differently. SO2, NO2 and PM10 concentration are measured as average per day. CO and O3 are more harmful and are measured as average per hour. The final API value is calculated per day.
The scale for each pollutant is non-linear, as is the final API score. Thus an API of 100 does not mean twice the pollution of API at 50, nor does it mean twice as harmful. While an API of 50 from day 1 to 182 and API of 100 from day 183 to 365 does provide an annual average of 75, it does not mean the pollution is acceptable even if the benchmark of 100 is deemed safe. This is because the benchmark is a 24 hour target. The annual average must match against the annual target. It is entirely possible to have safe air every day of the year but still fail the annual pollution benchmark.
API and Health Implications (Daily Targets)
The API has been in use in Hong Kong since June 1995. It is measured and updated hourly by the Environmental Protection Department (EPD). Moreover, the EPD makes forecast on the API for the following day everyday.
The API is based on the level of 6 atmospheric pollutants, namely sulfur dioxide (SO2), nitrogen dioxide (NO2), suspended particulates, carbon monoxide (CO), ozone (O3), lead (Pb), measured at all the monitoring stations throughout the territory.
There are 11 General Stations and 3 Roadside Stations. The former includes Central / Western, Eastern, Kwai Chung, Kwun Tong, Sha Tin, Sham Shui Po, Tai Po, Tap Mun, Tsuen Wan, Tung Chung, and Yuen Long; the later Causeway Bay, Central, and Mong Kok.
In Hong Kong, there are two types of API: General API and Roadside API. The EPD reports the latest APIs hourly.
The index and the air quality objectives were set in 1987; and pollutant levels are measured over varying periods, in Î¼g/m3. There are hourly, 24 hour and annual targets for sulfur dioxide and nitrogen dioxide, and 24 hour and annual targets for particulates.
The table below shows the official Health Implications of the respective API levels in Hong Kong.
In 1998, the Education Bureau's recommended schools to curtail outdoor activities when the index reached 200, whereas leading healthcare advocates are urging that the level be revised to 100. The World Health Organisation revised its air quality guideline levels of sulfur dioxide, nitrogen dioxide and ozone in 2006 in light of new scientific evidence. The WHO also introduced new measurement guidelines for very small particulates which are more dangerous to pulmonary function. At the '200' level, Hong Kong levels of SO2 (800Î¼g/m3) and NO2 (1,130Î¼g/m3) are 40 times and 5Â½ times WHO guidelines respectively; the equivalent for particulates (350Î¼g/m3) is 7 times WHO guidelines.
Similar to Hong Kong, the air quality in Malaysia is reported as the API or Air Pollution Index. Four of the index's pollutant components (i.e., carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide) are reported in ppmv but PM10 particulate matter is reported in Î¼g/m3.
This scale below shows the Health classifications used by the Malaysian government.
- 0-50 Good
- 51-100 Moderate
- 101-200 Unhealthy
- 201-300 Very unhealthy
- 301- Hazardous
If the API exceeds 500, a state of emergency is declared in the reporting area. Usually, this means that non-essential government services are suspended, and all ports in the affected area are closed. There may also be a prohibition on private sector commercial and industrial activities in the reporting area excluding the food sector.
The AP 42 Compilation of Air Pollutant Emission Factors, was first published by the U.S. Public Health Service in 1968. In 1972, it was revised and issued as the second edition by the U.S. Environmental Protection Agency (EPA). In 1985, the subsequent fourth edition was split into two volumes. Volume I includes stationary point and area sourceemission factors, and Volume II includes mobile source emission factors. Volume I is currently in its fifth edition and is available on the Internet. Volume II is no longer maintained as such, but roadway air dispersion models for estimating emissions from onroad vehicles and from non-road vehicles and mobile equipment are also available on the Internet.
In routine common usage, Volume I of the emission factor compilation is very often referred to as simply AP 42.
Air pollutant emission factors are representative values that attempt to relate the quantity of a pollutant released to the ambient air with an activity associated with the release of that pollutant. These factors are usually expressed as the weight of pollutant divided by a unit weight, volume, distance, or duration of the activity emitting the pollutant (e.g., kilograms of particulate emitted per megagram of coal burned). Such factors facilitate estimation of emissions from various sources of air pollution. In most cases, these factors are simply averages of all available data of acceptable quality, and are generally assumed to be representative of long-term averages.
The equation for the estimation of emissions before emission reduction controls are applied is:
- E = A Ã— EF
and for emissions after reduction controls are applied:
- E = A Ã— EF Ã— (1-ER/100)
Emission factors are used by atmospheric dispersion modelers and others to determine the amount of air pollutants being emitted from sources within industrial facilities.
Chapters in AP 42, Volume I, Fifth Edition
Chapter 5, Section 5.1 "Petroleum Refining" discusses the air pollutant emissions from the equipment in the various refinery processing units as well as from the auxiliary steam-generating boilers, furnaces and engines, and Table 5.1.1 includes the pertinent emission factors. Table 5.1.2 includes the emission factors for the fugitive air pollutant emissions from the large wet cooling towers in refineries and from the oil/water separators used in treating refinery wastewater.
The fugitive air pollutant emission factors from relief valves, piping valves, open-ended piping lines or drains, piping flanges, sample connections, and seals on pump and compressor shafts are discussed and included the report EPA-458/R-95-017, "Protocol for Equipment Leak Emission Estimates" which is included in the Chapter 5 section of AP 42. That report includes the emission factors developed by the EPA for petroleum refineries and for the synthetic organic chemical industry (SOCMI).
In most cases, the emission factors in Chapter 5 are included for both uncontrolled conditions before emission reduction controls are implemented and controlled conditions after specified emission reduction methods are implemented.
Chapter 7 "Liquid Storage Tanks" is devoted to the methodology for calculating the emissions losses from the six basic tank designs used for organic liquid storage: fixed roof (vertical and horizontal), external floating roof, domed external (or covered) floating roof, internal floating roof, variable vapor space, and pressure (low and high). The methodology in Chapter 7 was developed by the American Petroleum Institute in collaboration with the EPA.
The EPA has developed a software program named "TANKS" which performs the Chapter 7 methodology for calculating emission losses from storage tanks. The program's installer file along with a user manual, and the source code are available on the Internet.
Chapters 5 and 7 discussed above are illustrative of the type of information contained in the other chapters of AP 42. It should also be noted that many of the fugitive emission factors in Chapter 5 and the emissions calculation methodology in Chapter 7 and the TANKS program also apply to many other industrial categories besides the petroleum industry.
Estimating Air Emissions associated with Fossil Fuels and Stored Materials
The only emissions monitored are those associated with the burning of fossil fuels and the storage of some materials which generate toxic emissions. kWh are not monitored for emissions, and the discussion in this section does not address electricity.
There are three ways to monitor emissions of air contaminants:
- Annual or Biannual stack tests. This is a very expensive option.
- Continual Emissions Monitoring systems (CEM systems). This is also an expensive option.
- Parametric Monitoring, also known as AP42. This method converts fuel and electricity usage into emissions amounts using EPA emissions factors. This is the least expensive and most common method.
- The EPA usually will accept emissions data gathered using the AP42 method. However these emissions factors are averages and are based upon older less efficient equipment and may err on the high side. As a result some may choose alternative methods of tracking emissions. AP42 Emissions Factors for fossil fuels can be downloaded from the [http://www.epa.gov/ttn/chief/ap42/ EPA website].
Estimating Air Emissions associated with Electricity Usage
The EPA does not offer AP42 factors that convert kWh into emissions. Although the generation of electricity is often associated with pollutants fouling the air, this is not always the case. Electricity generation using Nuclear, Solar, Wind and Hydro does not pollute the air at all. Depending upon the hour of the day, the electricity used by an office building may come from Coal and Natural Gas which foul the air, or Nuclear, Solar or Hydro, which do not.
There are a few lists of emissions factors that convert kWh into likely amounts of emissions. The Department of Energy offers emissions factors that convert electricity into emissions. However, the [http://www.leonardoacademy.org Leonardo Academy] produced a more substantial list of emissions (CO2, VOCs, NOx, CO, SO2, PM10, Mercury, Cadmium and Lead) factors for the EPA in 1998, that Leonardo updates yearly using EPA Data. These emission factors are listed by State. Although there is no consensus on statewide emissions factors f
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Answers:Here are the six common pollutants according to EPA (US Environmental Protection Agency): 1. Ozone (O3) is a gas composed of three oxygen atoms. It is not usually emitted directly into the air, but at ground-level is created by a chemical reaction between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight. Ozone has the same chemical structure whether it occurs miles above the earth or at ground-level and can be "good" or "bad," depending on its location in the atmosphere. In the earth's lower atmosphere, ground-level ozone is considered "bad." Motor vehicle exhaust and industrial emissions, gasoline vapors, and chemical solvents as well as natural sources emit NOx and VOC that help form ozone. Ground-level ozone is the primary constituent of smog. Sunlight and hot weather cause ground-level ozone to form in harmful concentrations in the air. As a result, it is known as a summertime air pollutant. Many urban areas tend to have high levels of "bad" ozone, but even rural areas are also subject to increased ozone levels because wind carries ozone and pollutants that form it hundreds of miles away from their original sources. 2. Particulate matter also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets. Particle pollution is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles. 3. Carbon monoxide, or CO,is a colorless, odorless gas that is formed when carbon in fuel is not burned completely. It is a component of motor vehicle exhaust, which contributes about 56 percent of all CO emissions nationwide. Other non-road engines and vehicles (such as construction equipment and boats) contribute about 22 percent of all CO emissions nationwide. Higher levels of CO generally occur in areas with heavy traffic congestion. In cities, 85 to 95 percent of all CO emissions may come from motor vehicle exhaust. Other sources of CO emissions include industrial processes (such as metals processing and chemical manufacturing), residential wood burning, and natural sources such as forest fires. Woodstoves, gas stoves, cigarette smoke, and unvented gas and kerosene space heaters are sources of CO indoors. The highest levels of CO in the outside air typically occur during the colder months of the year when inversion conditions are more frequent. The air pollution becomes trapped near the ground beneath a layer of warm air. 4. Nitrogen dioxide (NO2) is one of a group of highly reactive gasses known as "oxides of nitrogen," or "nitrogen oxides (NOx)." Other nitrogen oxides include nitrous acid and nitric acid. While EPA s National Ambient Air Quality Standard covers this entire group of NOx, NO2 is the component of greatest interest and the indicator for the larger group of nitrogen oxides. NO2 forms quickly from emissions from cars, trucks and buses, power plants, and off-road equipment. In addition to contributing to the formation of ground-level ozone, and fine particle pollution, NO2 is linked with a number of adverse effects on the respiratory system. 5. Sulfur dioxide (SO2) is one of a group of highly reactive gasses known as oxides of sulfur. The largest sources of SO2 emissions are from fossil fuel combustion at power plants (73%) and other industrial facilities (20%). Smaller sources of SO2 emissions include industrial processes such as extracting metal from ore, and the burning of high sulfur containing fuels by locomotives, large ships, and non-road equipment. SO2 is linked with a number of adverse effects on the respiratory system. 6. Lead (Pb) is a metal found naturally in the environment as well as in manufactured products. The major sources of lead emissions have historically been motor vehicles (such as cars and trucks) and industrial sources. As a result of EPA's regulatory efforts to remove lead from gasoline, emissions of lead from the transportation sector dramatically declined by 95 percent between 1980 and 1999, and levels of lead in the air decreased by 94 percent between 1980 and 1999. Today, the highest levels of lead in air are usually found near lead smelters. Other stationary sources are waste incinerators, utilities, and lead-acid battery manufacturers.
Answers:Suspended Particulate Matter This is a mixture of solid and liquid particles suspended in the air. Suspended particulates are seen as dust, smoke, and haze which can make breathing difficult, especially for people with chronic respiratory problems. Volatile OrganicCompounds (VOCs) VOCs include gasoline, paint solvents, and organic cleaning solutions. They evaporate and enter the air as vapour, and as molecules resulting from the incomplete burning of fuels and wastes. Carbon Monoxide (CO) One source of carbon monoxide is vehicle emissions. This is an invisible, odourless gas that is highly toxic to air-breathing animals because it interferes with the blood's ability to transport oxygen. Even low levels can start or increase damage to the heart in individuals with artery or heart problems. At medium concentrations, carbon monoxide causes headaches and fatigue. As the concentration increases, reflexes slow down and drowsiness occurs. At high levels carbon monoxide causes death. People at greatest risk from carbon monoxide include pregnant women, infants, and those with heart or respiratory diseases. Nitrogen Oxides (NOX) Nitrogen Oxides are lung irritants that can lead to acute respiratory diseases in children. They may also cause over-sensitivity to pollen and dust in people suffering from asthma. Sulphur Oxides (SOX) Sulphur Dioxide is converted to sulphuric acid in the atmosphere. It can be poisonous to both plants and animals. Like particulates, sulphur dioxide irritates the respiratory tract, causing airways to close, and interfering with the lungs. Children and the elderly are especially sensitive to sulphur dioxide, as are people suffering from asthma and emphysema. Lead & other heavy metals Lead is dangerous, even at low concentrations and can lead to reduced intelligence in children, brain damage and death. It accumulates in the body and damages body tissue. Ground Level Ozone Ozone in the upper atmosphere shields us from ultraviolet radiation. However on ground level, it is highly toxic to both plants and animals as it can damage lungs. It can bring on coughing, asthma attacks and lower the immune system. Fuel wood Indoor air pollution is caused by the burning of fuel-wood and dung for cooking, and can cause suffocation. Sources of Air pollution Motor vehicles The two main sources of air pollution are motor vehicles & industries. When they burn petrol, cars and trucks release significant quantities of sulphur dioxide, oxides of nitrogen, carbon monoxide, lead, and suspended particulate matter. Lead used in petrol to protect engines is also dangerous. Diesel powered cars produce large quantities of particulates in the form of black soot. Reduced use of private cars, proper legislation and enforcement of laws can curb this menace. Industry Electrical power plants and industries emit particulate matter, sulphur oxides, nitrogen oxides, hydrocarbons and carbon dioxides. The top three industrial sources of toxic air pollutants are the chemical, metal, and paper industries. Municipal Solid Waste When solid waste is burnt, heavy metals like lead, gases and soot are spread over residential areas. Rubbish, dust and gases found during the decomposition of waste, all contribute to air pollution. Smog When air pollution in urban areas reduces visibility it is often called smog. There are different types of smog. Smoke pollution from industries is sometimes called industrial smog. The pollutants it contains are sulphur oxides and particulates. Photochemical smog is a brownish orange haze formed by chemical reactions involving sunlight. Medical waste Burning medical waste is a serious source of air pollution, particularly in cities. Most incinerators are rudimentary by today's standards. They burn waste incompletely, releasing acidic gases, heavy metals, and dioxins into the air. Developing countries As developing countries become more industrialised, they also produce more air pollution. The leaders of most developing countries believe they must become industrialised rapidly in order to be economically competitive. Environmental quality is usually a low priority in the race to develop. Thus, while air quality is slowly improving in developed countries, it is rapidly deteriorating in developing countries. Improving the well being of developing nations does not have to result in increased pollution. The key to future development lies in providing the products and services which people want by using the most efficient technologies, and consuming the lowest possible level of resources. How does air pollution affect us? Exposure to low levels of pollutants such as ozone, sulphur oxides, nitrogen oxides, and particulates, irritates eyes and causes inflammation of the respiratory tract. Evidence exists that many air pollutants also suppress the immune system, increasing susceptibility to infection. In addition, evidence continues to accumulate indicating that exposure to air pollution during respiratory illnesses may result in people developing chronic respiratory diseases, such as emphysema and bronchitis as they get older. Other health problems that can result from long-term exposure to toxic air-pollutants are cancer, chronic obstructive pulmonary disease, asthma, respiratory infections, and cardiovascular disease. Air pollution can also cause acidification of lakes and soils and impacts on crop productivity, forest growth, and biodiversity. Some research indicates that the ozone and sulphur dioxide is reducing crop yields. The potential for crop losses in Asia has been indicated by a study in Pakistan where a 40 per cent reduction in rice yields was linked to the presence of pollutants in the air. What can we do? Encourage people to leave their car at home and walk or ride a bicycle to travel short distances. Develop efficient public transport systems to help reduce dependence on private cars. Provide Government subsidies to encourage the introduction of petrol with low sulphur and no lead. Focus on regional inter-Governmental cooperation. Pollutants can be carried from one country to another, so individual countries cannot solve the associated problems alone. Currently, regional/sub-regional agreements on air pollution either do not exist or are at initial stages. Promote energy efficiency and conservation. Energy efficiency means using technology to accomplish tasks with less energy. Energy conservation focuses on cutting down on wasteful energy consuming activities. These approaches are not only cost effective ways of reducing harmful emissions from industries and vehicles, but they also give us time to search for safer and cheaper alternative energy sources. Use smaller, more efficient cars as they consume less fuel and so produce fewer emissions. Design cars so that combustion temperatures are lower and less nitrogen oxide is formed. Use lighter materials and better designed cars. Currently available technology already makes it possible for cars to have fuel efficiencies of 60-65 miles per gallon. Find better alternative fuels, as petroleum reserves will not last for ever. Alcohol, solar power, electricity and liquid hydrogen are some of the options that car manufacturers have investigated in the search for alternative fuels. Although cars that can use these fuels have already been designed or are currently being worked on, the cost and accessibility of fuel remains a problem. All alternative fuels will not necessary be environmentally friendly. For instance, if the electricity for electricity-powered cars is produced by coal-fired power plants, the eventual volume of emissions will be higher than for conventionally fuelled cars. Fit smoke-stacks with electrostatic precipitators, fabric filters, scrubbers, or other technologies to remove particulate matter. Use careful land-excavating methods to control particulates. For example, water can be sprinkled on dry soil that is being moved during road construction. Remove sulphur dioxide from fuel by switching to a low-sulphur fuel
Answers:By definition, a pollutant is something which humans introduce to the environment that would not otherwise be there and in most cases is undesirable. This can cover many things, i.e. 'noise' pollution. The oil industry is trying to do anything they can to slow down regulations and restrictions which could threaten them, and understandably so. But you need to recognize, that their attempt to say that CO2 is not pollution is a sneaky Big Tobacco tactic. Of course it is not a pollutant... (uh, unless you refer to what defines a pollutant... under those circumstances, it can be a pollutant, and is considered as such, but is of course being aggressively challenged by the oil and automotive industry, etc.). This is why... not CO2, but rather, CO2 MADE BY MAN and trillions of pounds of the gas released unnaturally into our atmosphere, every single day... that is a pollutant. Had we not intervened, it wouldn't exist, instead, the principle properties that help to create it would be safely tucked away, as other forms of liquid, goo or rock, buried deep in the ground, where it has been for millions of years, but through a chemical process, we convert these fossilized elements which are not CO2 (yet), into a gas. There you go, by pure definition, a pollutant, simply because we put it there. Furthermore, it is undesirable. Yes, we live with it, we need it, but at no point in the last half a million years or more (including several cycles of ice ages and interglacial warming trends), have CO2 levels been as high as they are now, not even close, meaning, what we are putting up there from burning fossil fuels, we don't need. And we know CO2 is a green house gas, which absorb heat, this raises heat both in the atmosphere and in the oceans, the largest CO2 sink which exists. Everything we do to disturb nature is pollution. Everything we put into the air that wouldn't exist otherwise, is a pollutant. The industries are just playing with words and twisting their meanings to get what they want... Sound familiar?... "I, did not, have, 'sexual relations', with that woman, Monica Lewinsky!" - keyword 'sexual relations', because he thought if busted, he could cleverly explain his way out of it by stating how he interprets the definition of the term as meaning by it's full definition... sexual activities which include 'intercourse'. And as we all would soon see afterwards, he did try to make that case, didn't he... Same idea... don't buy into it... that's just politics for you. CO2 does occur naturally, but not in all cases, if we 'manufacture' it and release it carelessly into the environment despite any effect which could and will result... we are polluting. Best is to go with hydrogen and things like that, less pollution. (see, you wouldn't even be able to say that in a sentence if anthropogenic CO2 wasn't considered a pollutant, now what's the sense in that??). Ulitmately, this is all about money, well, and power of course. "Whoever controls the world's oil, controls the world". Well, at least they'll still be rich and getting richer, that's how the oil people like it. But hey... anyone here who can make a good enough case why Anthropogenic CO2 really isn't a pollutant; Exxon-Mobil will gladly pay you min. $10,000... and that, is a fact. So those of you who are trying... keep it up, maybe you'll hit paydirt! [Edit] lol - 5 thumbs down woohoo! thanks... must have hit a nerve with you AGW deniers - good! [Edit] Bob326... let's put this to bed shall we... YOU SAID: "CO2 is natural, and is necessary for nearly all living things." RESPONSE: for that, just click here, this totally explains everything, including why or how a question like this one could even come up in the first place... http://www.wunderground.com/education/cei.asp YOU SAID: "So, it is just human's that can pollute? Aren't a part of nature? Aren't we an animal?" RESPONSE: for that, see my response below... Geography Dictionary: pollution A substance which causes an undesirable change in the physical, chemical, or biological characteristics of the natural environment. Although there are some natural pollutants such as volcanoes, pollution generally occurs because of human activity. Biodegradable pollutants, like sewage, cause no permanent damage if they are adequately dispersed, but non-biodegradable pollutants, such as lead, may be concentrated as they move up the food chain. Within Western Europe, air pollution, associated with basic industries such as oil refining, chemicals, and iron and steel, as well as with the internal combustion engine, is probably the principal offender, followed by water and land pollution. Other forms of environmental pollution include noise, and the emission of heat into waterways which may damage aquatic life. Present-day problems of pollution include acid rain and the burning of fossil fuels to produce excessive carbon dioxide. A substance or condition that contaminates air, water, or soil. Pollutants can be artificial substances, such as pesticides and PCBs, or naturally occurring substances, such as oil or carbon dioxide, that occur in harmful concentrations in a given environment. Heat transmitted to natural waterways through warm-water discharge from power plants and uncontained radioactivity from nuclear wastes are also considered pollutants. - The American Heritage Science Dictionary Common environmental pollutants include: sewage, garbage, radiation, carbon monoxide, automobile exhaust, pesticides, chloroflurocarbons, CFCs, polychlorinated biphenyls, PCBs, hydrocarbons, carbon dioxide, dioxin, ethylene dibromide, EDB; tobacco smoke, wood smoke, coal smoke; asbestos, lead, chlorine, mercury; noise, nuclear waste, solid waste. - Webster's New World College Dictionary Major primary pollutants produced by human activity include: "Carbon Dioxide" Pollutants can be classified as either primary or secondary. Primary pollutants are substances directly emitted from a process, such as ash from a volcanic eruption or the carbon monoxide gas from a motor vehicle exhaust. - http://en.wikipedia.org/wiki/Air_pollution#Pollutants On March 13, 2001, President Bush backed away from his campaign pledge to seek cuts in emissions of carbon dioxide -- the main cause of global warming -- as part of a strategy to regulate together, rather than separately, four air pollutants emitted by power plants. In a letter to Sen. Chuck Hagel (R-Neb.) explaining his reversal, the president cited a recent Department of Energy report that concluded it would be too costly to regulate CO2; Bush also falsely claimed that "Carbon dioxide IS NOT CONSIDERED A POLLUTANT UNDER THE CLEAN AIR ACT" This, of course, was just a hair-splitting interpretation of current law, one that provided no logical basis for the president to drop his promise to seek a new law to control CO2. But it is worth noting that the president is also wrong in his legal claim. FACT: From 1970 up to the time that Bush made this statement and excuse CO2 was in fact listed as a 'pollutant' under the Clean Air Act, as well as in the real world. How does the Clean Air Act define "air pollutant"? The act says that an air pollutant is any "physical, chemical, biological, [or] radioactive . . . substance or matter which is emitted into or otherwise enters the ambient air." (CAA, sec. 302(g)) CO2 is certainly a chemical substance and it is emitted into the ambient air when fossil fuel is burned in vehicles and power plants. Also... In section 103(g) of the act, Congress explicitly included emissions of CO2 from fossil fuel power plants in a list of air pollutants that it directed the Environmental Protection Agency to include in pollution prevention programs. Section 103(g) of the act calls for "[i]mprovements in nonregulatory strategies and technologies for preventing or reducing multiple air pollutants, including sulfur oxides, nitrogen oxides, heavy metals, PM-10 (particulate matter), carbon monoxide, and carbon dioxide, from stationary sources, including fossil fuel power plants." (Emphasis added) Despite this (d
Answers:About Plastic Pollution Plastic is one of the few new chemical materials which pose environmental problem. Polyethylene, polyvinyl chloride, polystyrene is largely used in the manufacture of plastics. Synthetic polymers are easily molded into complex shapes, have high chemical resistance, and are more or less elastic. Some can be formed into fibers or thin transparent films. These properties have made them popular in many durable or disposable goods and for packaging materials. These materials have molecular weight ranging from several thousands to 1,50,000. Excessive molecular size seems to be mainly responsible for the resistance of these chemicals to bio-degradation and their persistence in soil environment for a long time. Plastic in the environment is regarded to be more an aesthetic nuisance than a hazard, since the material is biologically quite inert. The plastic industry in the US alone is $ 50 billion per year and is obviously a tempting market for biotechnolo gical enterprises. Biotechnological processes are being developed as an alternative to existing route or to get new biodegradable biopolymers . 20% of solid municipal wastes in US is plastic. Non-degradable plastics accumulate at the rate of 25 million tonnes per year. According to an estimate more than 100 million tonnes of plastic is produced every year all over the world. In India it is only 2 million tonnes. In India use of plastic is 2 kg per person per year while in European countries it is 60 kg per pe rson per year while that in US it is 80 kg per person per year Causes Of Plastic Pollution Plastics are used because they are easy and cheap to make and they can last a long time. Unfortunately these same useful qualities can make plastic a huge pollution problem. Because the plastic is cheap it gets discarded easily and its persistence in the environment can do great harm. Urbanisation has added to the plastic pollution in concentrated form in cities. Plastic thrown on land can enter into drainage lines and chokes them resulting into floods in local areas in cities as experienced in Mumbai, India in 1998. It was claimed in one of the programmes on TV Channel that eating plastic bags results in death of 100 cattles per day in U.P. in India. In stomach of one dead cow, as much as 35 kg of plastic was found. Because plastic does not decompose, and requires high energy ultra-violet light to break down, the amount of plastic waste in our oceans is steadily increasing. More than 90% of the articles found on the sea beaches contained plastic. The plastic rubbish found on beaches near urban areas tends to originate from use on land, such as packaging material used to wrap around other goods. On remote rural beaches the rubbish tends to have come from ships, such as fishing equipment used in the fishing industry. This plastic can affect marine wildlife in two important ways: by entangling creatures, and by being eaten. Turtles are particularly badly affected by plastic pollution, and all seven of the world's turtle species are already either endangered or threatened for a number of reasons. Turtles get entangled in fishing nets, and many sea turtles have been found dead with plastic bags in their stomachs.Turtles mistake floating transperent plastic bags for jellyfish and eat them. In one dead turtle found off Hawaii in the Pacific more than 1000 pieces of plastic were found in the stomach. A recent US report concluded that more than 100000 marine mammals die each year in the world's oceans by eating or becoming entangled in plastic rubbish, and the position is worsening World-wide, 75 marine bird species are known to eat plastic articles. This includes 36 species found off South Africa. A recent study of blue petrel chicks at South Africa's remote Marion Island showed that 90% of chicks examined had plastic in their stomachs apparently fed to them accidentally by their parents. South African seabirds are among the worst affected in the world. Plastics may remain in the stomachs, blocking digestion and possibly causing starvation Processing of Bioplastics Presence of nucleating agents (which facilitate crystallization) or the use of plasticiser shortens the processing cycles during the moulding operations. There are two main points about processing of PHBV bioplastics - (i) The limited thermal stability of the polymer and so it degrades rapidly above 195 degree centi. (ii) The need to optimise conditions to allow a maximum crystallization rate (which reduces cycle times). The maximum rate of crystallization is reported to be at about 55-60 degree centi. which is significantly closer to Tg than the Tm. Processing temperatures should not exceed 180 degree centi. and duration of time when the material is in melt state should be kept minimum. At the end of a run the processing equipment should be purged with polyethylene. When blow moulding the blow-pin and the mould should be at about 60 degree centi. to optimise crystallisation rates. Similarly injection moulds are recommended at 55-65 degree centi. The low-hydroxyvalerate, unplasti