Acid Rain - PowerPoint by FOX55

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




  Wet deposition: refers to acidic rain, fog, and snow. As this acidic water
 flows over and through the ground, it affects a variety of plants and animals.
 The strength of the effects depend on many factors, including how acidic the
  water is, the chemistry and buffering capacity of the soils involved, and the
       types of fish, trees, and other living things that rely on the water.
Dry deposition: refers to acidic gases and particles. About half of the
acidity in the atmosphere falls back to earth through dry deposition. The
 wind blows these acidic particles and gases onto buildings, cars, homes,
  and trees. Dry deposited gases and particles can also be washed from
 trees and other surfaces by rainstorms. When that happens, the runoff
  water adds those acids to the acid rain, making the combination more
                    acidic than the falling rain alone.
Organism response to soluble aluminum within lakes:
 Scientists have become particularly interested in "indicator species" -
species which suffer acute toxicity, sickness or death because of chronic
exposure to quite low concentrations of a contaminant. Such indicator
species are key to identifying a lake or a stream, the health of which is
deteriorating due to the degrading quality of water.
Acid rain is rain with a pH (a logarithmic measurement of acidity or alkalinity)
of less than 5.7. Acid rain usually results from elevated levels of nitric and
sulfuric acids in air pollution. Acidic pollutants that can lead to acid rain are
common by-products from burning fossil fuels (e.g., oil, coal, etc.) and are
found in high levels in exhaust from internal combustion engines (e.g.,
automobile exhaust). Acidic precipitation may also occur in other forms such
as snow.
Acid rain occurs when polluted gasses become trapped in clouds. The clouds
may drift for hundreds, even thousands, of miles before finally releasing
acidic precipitation. Trees, lakes, animals, and even buildings are vulnerable
to the slow corrosive effects of acid rain, whose damaging components are
emitted by power plants and factories, especially those burning low grades of
coal and oil.
Acid rain was first recognized in 1872, approximately 100 years after the start
of the Industrial Revolution in England, when an English scientist, Robert
Angus Smith (1817–1884), pointed out the problem. Almost another century
passed, however, before the public became aware of the damaging effects of
acid rain. In 1962, the Swedish scientist Svante Oden brought the



acid rain quandary to the attention of the press, instead of the less
popular scientific journals. He compiled records from the 1950s
indicating that acid rain came from air masses moving out of central
and Western Europe into Scandinavia.
After acid rain was discovered in Europe, scientists began measuring the
acidity of rain in North America. Initially, they found that the problem was
concentrated in the northeastern states of New York and Pennsylvania
because the type of coal burned there was more sulfuric. By 1980, most of
the states east of the Mississippi, as well as southeastern Canada, were
receiving acidic rainfall. Acid rain falls in the West also, although the problem
is not as severe. Acid rain in Los Angeles, California is caused primarily by
local traffic emissions. Car emissions contain nitrogen oxide, the second
highest problematic gas in acid rain after sulfur dio


Acid rain is measured through pH tests that determine the concentration of
hydrogen ions. Pure water has a neutral pH of approximately 7.0. When the
pH is greater than 7, the material is thought to be alkaline. At a pH of 5.7, rain
is slightly acidic, but when its pH is further reduced, the rain becomes an
increasingly stronger acid rain. In the worst cases, acid rain has shown a pH
of 2.4 (about as acidic as vinegar). When pH levels are drastically tipped in
soil and water, entire lakes and forests are jeopardized.
Evergreen trees in high elevations are especially vulnerable. Although the
acid rain itself does not kill the trees, it makes them more susceptible to
other dangers. High acid levels in soil causes leaching of other valuable
minerals such as calcium, magnesium, and potassium. According to the
World Watch Institute, in the late 1980s and early 1990s forest damage in
Europe ranged from a low of 4% in Portugal to a high of 71% in
Czechoslovakia, averaging 35% overall.


Small marine organisms cannot survive in acidic lakes and rivers, and their
depletion affects larger fish and ultimately the entire marine life food chain.
Snow from acid rain is also damaging; snowmelt has been known to cause
massive, instant death for many kinds of fish. Some lakes in Scandinavia,
for example, are completely devoid of fish. Acid rain also eats away at
buildings and metal structures. From the Acropolis in Greece to
Renaissance buildings in Italy, ancient structures are showing signs of slow
corrosion from acid rain. In some industrialized parts of Poland, trains
cannot exceed 40 miles (65 km) per hour because the iron railway tracks
have been weakened from acidic air pollution
New power plants in the United States are being built with strict emissions
standards, but retrofitting older plants is difficult and expensive.
Nevertheless, the United States Environmental Protection Agency requires
most of the older and dirtier power plants to install electrostatic
precipitators and bughouse filters—devices designed to remove solid
particulates. Such devices are required in Canada, in industrialized
countries in Western Europe, and in Japan. Scrubbers, or flue-gas
desulfurization technology, are also being used because of their
effectiveness in removing as much as 95% of a power plant's sulfur dioxide
emissions. These devices are expensive, however, and there are clauses in
pollution control laws that allow older plants to continue operation at higher
pollution levels.

acid rain is for power plants to burn cleaner coal in their plants. This does
not require retrofitting but it does increase transportation costs since coal
containing less sulfur is mined in the western part of the United States, far
away from where it is needed in the Midwest and eastern part of the
country.
Prevailing winds blow the compounds that cause both wet and dry acid deposition
across state and national borders, and sometimes over hundreds of miles.
Organism response to soluble aluminum within lakes:
 Scientists have become particularly interested in "indicator species" - species which suffer acute toxicity,
sickness or death because of chronic exposure to quite low concentrations of a contaminant. Such
indicator species are key to identifying a lake or a stream, the health of which is deteriorating due to the
degrading quality of water.
Acid rain is rain with a pH (a logarithmic measurement of acidity or alkalinity) of less than 5.7. Acid rain
usually results from elevated levels of nitric and sulfuric acids in air pollution. Acidic pollutants that can
lead to acid rain are common by-products from burning fossil fuels (e.g., oil, coal, etc.) and are found in
high levels in exhaust from internal combustion engines (e.g., automobile exhaust). Acidic precipitation
may also occur in other forms such as snow.
Acid rain occurs when polluted gasses become trapped in clouds. The clouds may drift for hundreds, even
thousands, of miles before finally releasing acidic precipitation. Trees, lakes, animals, and even buildings
are vulnerable to the slow corrosive effects of acid rain, whose damaging components are emitted by
power plants and factories, especially those burning low grades of coal and oil.
Acid rain was first recognized in 1872, approximately 100 years after the start of the Industrial Revolution
in England, when an English scientist, Robert Angus Smith (1817–1884), pointed out the problem. Almost
another century passed, however, before the public became aware of the damaging effects of acid rain. In
1962, the Swedish scientist Svante Oden brought the
acid rain quandary to the attention of the press, instead of the less popular scientific journals. He
compiled records from the 1950s indicating that acid rain came from air masses moving out of central
and Western Europe into Scandinavia.

After acid rain was discovered in Europe, scientists began measuring the acidity of rain in North
America. Initially, they found that the problem was concentrated in the northeastern states of New York
and Pennsylvania because the type of coal burned there was more sulfuric. By 1980, most of the states
east of the Mississippi, as well as southeastern Canada, were receiving acidic rainfall. Acid rain falls in
the West also, although the problem is not as severe. Acid rain in Los Angeles, California is caused
primarily by local traffic emissions. Car emissions contain nitrogen oxide, the second highest
problematic gas in acid rain after sulfur dioxide.

Acid rain is measured through pH tests that determine the concentration of hydrogen ions. Pure water
has a neutral pH of approximately 7.0. When the pH is greater than 7, the material is thought to be
alkaline. At a pH of 5.7, rain is slightly acidic, but when its pH is further reduced, the rain becomes an
increasingly stronger acid rain. In the worst cases, acid rain has shown a pH of 2.4 (about as acidic as
vinegar). When pH levels are drastically tipped in soil and water, entire lakes and forests are
jeopardized.

 Evergreen trees in high elevations are especially vulnerable. Although the acid rain itself does not kill
the trees, it makes them more susceptible to other dangers. High acid levels in soil causes leaching of
other valuable minerals such as calcium, magnesium, and potassium. According to the World Watch
Institute, in the late 1980s and early 1990s forest damage in Europe ranged from a low of 4% in
Portugal to a high of 71% in Czechoslovakia, averaging 35% overall.

Small marine organisms cannot survive in acidic lakes and rivers, and their depletion affects larger fish
and ultimately the entire marine life food chain. Snow from acid rain is also damaging; snowmelt has
been known to cause massive, instant death for many kinds of fish. Some lakes in Scandinavia, for
example, are completely devoid of fish. Acid rain also eats away at buildings and metal structures.
From the Acropolis in Greece to Renaissance buildings in Italy, ancient structures are showing signs of
slow corrosion from acid rain. In some industrialized parts of Poland, trains cannot exceed 40 miles (65
km) per hour because the iron railway tracks have been weakened from acidic air pollution
New power plants in the United States are being built with strict emissions standards, but retrofitting older
plants is difficult and expensive. Nevertheless, the United States Environmental Protection Agency
requires most of the older and dirtier power plants to install electrostatic precipitators and bughouse
filters—devices designed to remove solid particulates. Such devices are required in Canada, in
industrialized countries in Western Europe, and in Japan. Scrubbers, or flue-gas desulfurization
technology, are also being used because of their effectiveness in removing as much as 95% of a power
plant's sulfur dioxide emissions. These devices are expensive, however, and there are clauses in pollution
control laws that allow older plants to continue operation at higher pollution levels. Another way to reduce
acid rain is for power plants to burn cleaner coal in their plants. This does not require retrofitting but it
does increase transportation costs since coal containing less sulfur is mined in the western part of the
United States, far away from where it is needed in the Midwest and eastern part of the country.
Prevailing winds blow the compounds that cause both wet and dry acid deposition across state and national borders,
and sometimes over hundreds of miles.
The precursors, or chemical forerunners, of acid rain formation result from both natural sources, such as volcanoes
and decaying vegetation, and man-made sources, primarily emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx)
resulting from fossil fuel combustion. Acid rain occurs when these gases react in the atmosphere with water, oxygen,
and other chemicals to form various acidic compounds. The result is a mild solution of sulfuric acid and nitric acid
Scientists discovered, and have confirmed, that sulfur dioxide (SO2) and nitrogen oxides (NOx) are the primary causes
of acid rain. In the US, About 2/3 of all SO2 and 1/4 of all NOx comes from electric power generation that relies on
burning                         fossil                      fuels                        like                        coal.

Acid rain occurs when these gases react in the atmosphere with water, oxygen, and other chemicals to form various
acidic compounds. Sunlight increases the rate of most of these reactions. The result is a mild solution of sulfuric acid
and nitric.
The objective of the Project is to control acid rain and air pollution in Anhui Province to reduce adverse human health
impacts, improve agriculture and forest productivity and protect the environment. The Project will help:
(i)Formulate measures for improving the policy framework for reduction of sulfur dioxide and other acid rain causing
gas emissions.
(ii)Support a set of subproject that promote cleaner production, reduce acid rain and air pollution, and improve the
environment.

(i)Institutional strengthening for environmental monitoring and enforcement including human resource development.
  Contaminants that can affect the quality and usefulness of water are chemical, physical or biological.
                          Contaminants are either primary or secondary.
Primary contaminants: affect the health of humans or the health of aquatic life such as fisheries, aquatic
                                               plants and insects.
    Secondary contaminants: affect the taste, smell, color, and comfort of water. Although secondary
  contaminants may cause unwillingness toward use of the water, they pose no threat to the health of us or
                                              aquatic ecosystems.
 On the contrary, primary contaminants do pose a threat to health. To avoid public and environmental health
    problems associated with such contaminants, we must be aware of the degree of toxicity of them. We
     describe the toxicity of a substance on a dose-response relationship. The length of exposure and the
        concentration of the contaminant may result in either acute or chronic toxicity to the organism.
     Throughout the world, acid rain and acid deposition are serious threats to the health of lake and river
  ecosystems located near industrial cities. Many lakes in the U.S. and Europe are fishless because of the
 chronic effects of acid rain. The problem with these lakes is not specifically the acidic water; there are many
   lakes around the world with equally low water pH and yet they still contain fish. These fishless lakes are
located on and near rocks and soils that contain aluminum. The aluminum can easily leach from these rocks
             and soil when exposed to acidic water introduced from acid rain and acid deposition.
   The Acid Rain Program was created to implement Title IV of the 1990 Clean Air Act Amendments.
   The purpose of Title IV is to reduce the adverse effects of acid deposition through reductions in
   annual emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) by 10 million tons and by 2
   million tons below projected levels, respectively.
   Sulfur dioxide (SO2) and nitrogen oxides (NOx) are the key pollutants in the formation of acid rain.
   These pollutants also contribute to the formation of fine particles (sulfates and nitrates) that are
   associated with significant human health effects and regional haze. Additionally, NOx combines with
   volatile organic compounds (VOCs) to form ground-level ozone (smog) and nitrates that are
   transported and deposited at environmentally detrimental levels in parts of the country. These
   pollutants, in their various forms, lead to the acidification of lakes and streams rendering some of
   them incapable of supporting aquatic life. In addition, they impair visibility in our national parks,
   create respiratory and other health problems in people, weaken forests, and degrade monuments
   and buildings.
In the United States, the electric power industry accounts for approximately 67 percent of total annual SO2
                 emissions and slightly more than 20 percent of total annual NOx emissions.
 Since the start of the Acid Rain Program in 1995, the lower SO2 and NOx emission levels from the power
    sector have contributed to significant air quality and environmental and human health improvements.
                                Since its inception, the Acid Rain Program has:
          Reduced SO2 emissions by over 5.5 million tons from 1990 levels, or about 35 percent of total
       emissions from the power sector. Compared to 1980 levels, SO2 emissions from power plants have
                             dropped by more than 7 million tons, or about 41 percent.
         Cut NOx emissions by about 3 million tons from 1990 levels, so that emissions in 2005 were less
        than half the level anticipated without the program. Other efforts, such as the NOx Budget Trading
                Program in the eastern United States, also contributed significantly to this reduction.
          Led to significant cuts in acid deposition, including reductions in sulfate deposition of about 36
      percent in some regions of the United States and improvements in environmental indicators, such as
                                                  fewer acidic lakes.
      Provided the most complete and accurate emission data ever developed under a federal air pollution
      control program and made that data available and accessible by using comprehensive electronic data
             reporting and Web-based tools for agencies, researchers, affected sources, and the public.
      Served as a leader in delivering e-government, automating administrative processes, reducing paper
                           use, and providing online systems for doing business with EPA.
           Resulted in nearly 100 percent compliance through rigorous emissions monitoring, allowance
           tracking, and an automatic, easily understood penalty system for noncompliance. Flexibility in
                                compliance strategies reduced implementation costs.
A 2005 study (PDF) (15pp., 532 K) estimates that in 2010, the Acid Rain Program's annual benefits will be
  approximately $122 billion (2000$), at an annual cost of about $3 billion - a 40-to-1 benefit-to-cost ratio.
 The Acid Rain Program 2005 Progress Report includes special sections on fuel switching and compliance
 options, EPA's framework for accountability, program costs and benefits, surface water quality monitoring,
  impact assessment, environmental justice, and the Clean Air Rules. Building on the Acid Rain Program
  model, EPA promulgated the Clean Air Interstate Rule (CAIR), to address transport of fine particles and
   ozone in the eastern United States, the Clean Air Mercury Rule (CAMR) to reduce nationwide mercury
emissions from power plants, and the Clean Air Visibility Rule (CAVR) to improve visibility in national parks
                                             and wilderness areas.
           Acid Rain is Causing Loss of Valuable Northeast Sugar Maples

  DECADES OF ACID RAIN IS CAUSING LOSS OF VALUABLE NORTHEAST SUGAR MAPLES, CORNELL RESEARCHERS
                                                                WARN
Acid rain, the environmental consequence of burning fossil fuels, running factories and driving cars, has altered soils and
  reduced the number of sugar maple trees growing in the Northeast, according to a new study led by Cornell University
                                                             researchers.
  The sugar maple is the most economically valuable tree species in the eastern United States because of its high-priced
                                          lumber, syrup and tourist-attracting fall colors.
  The study, whose lead author, Stephanie Juice, was an undergraduate when the research was conducted, suggests that
 because acid rain makes the soil more acidic, unfavorable conditions are created for sugar maples. In acidic soils, sugar
maples produce fewer seedlings that survive and mature, and more adult trees die, the researchers found. They drew these
 conclusions after adding nutrients to soil in a test plot and reproducing the favorable soil conditions that existed prior to
                20th century industrial pollution. The result: Sugar maples on the plot rebounded dramatically.
The study provides "the most conclusive evidence to date" that the decline of sugar maples is linked to the effects of acid
  rain produced by human activity, said Timothy Fahey, professor of forest ecology at Cornell and co-author of the study,
     which is published in the May issue of Ecology. Juice wrote the main part of the paper as part of her senior thesis.
"The research addresses how a long-term, human-caused change in the environment is affecting sugar maples, which are
valuable both ecologically and economically as one of the dominant species in our region," said Juice, who now works for
   the Institute of Ecosystem Studies in Millbrook, N.Y., as a project assistant and is applying to the Peace Corps for next
                                                                 year.
The research was conducted at Hubbard Brook Experimental Forest (HBEF), a 3,160-hectare (7800-acre) reserve near North
Woodstock, N.H., where scientists have measured soil composition for the past 50 years. The scientists added nutrients in
          a test plot to replicate soil conditions that existed prior to the loss of sugar maples over the past 25 years.
  Nitric and sulphuric acid in acid rain leaches calcium from the soil. Calcium is the second most abundant plant nutrient
  (after nitrogen). In addition, the loss of calcium leads directly to more acidic soils. When soils become too acidic, such
         trees as sugar maples become stressed and have a harder time growing or producing seeds and seedlings.
 "Because of the detailed measurements for the last 50 years, we know almost exactly how much calcium was removed by
                                            acid rain," said Fahey. "Our treatment was
designed to replace just that amount of calcium to bring the system to what it was like prior to the acid rain era."
The study used two 10-hectare (25-acre) watersheds. On one 25-acre site, a calcium-rich mineral called wollastonite was spread in pellet form by helicopter in
October 1999. The other site served as a control.
While the pellets dissolve slowly over five to 10 years, the researchers were surprised to find that by summer 2002, the soil acidity in both the top and lower
layers of the test plot neutralized from being highly acidic to more acceptable levels for sugar maples. The researchers also found that by the second year,
calcium levels in the maples' leaves had risen.
Acid rain also increases levels of the trace nutrient manganese in the soil, which can be toxic to trees in higher doses. By year four and five, manganese in the
leaves had declined to healthier levels. In addition, seed production and the density and size of sugar maple seedlings all increased in the few years following
treatment, compared with the untreated neighboring plot.
The researchers also found that the communities of mycorrhizae -- soil fungi that help provide more nutrients to plant roots -- were substantially greater around
the roots of both seedlings and mature sugar maples in the treated plot. Future research will explore the relationship between mycorrhizae and acid rain.
Though pollution-control legislation has helped reduce sulphuric acid by one-third since its high point in the 1960s, nitric acid from automobiles has not
significantly declined.
This research was supported by the National Science Foundation and the Hubbard Brook Ecosystem Study.

Hydrological Cycle
Sometimes aquifers can be found only a few meters from the ground surface, while in
other places it is necessary to bore a well hundreds of meters down in order to reach
water. Some aquifers recharge over a long period of time as water slowly seeps down
through the rock. Others are known as fossil aquifers, because the water is no longer
being recharged. Ice caps and aquifers can be seen as long-term water storage
mechanisms
, while lakes, seas, and oceans provide short-term storage. The oceans, which cover more
than 70% of the Earth's surface, control the hydrological cycle and indeed the whole
ecosystem
 of the planet.
The Cycle`
The Sun's heat drives the hydrological cycle. As wind blows across the
surface of the ocean, this heat causes water to evaporate from the sea and
become absorbed into the air as water vapour—the amount absorbed
depends on the temperature of the water.
If the ocean is dominated by a cold current, such as the Benguela Current off
southwest Africa, or the Humboldt Current which flows up the western coast of
South America, very little evaporation will take place. This is why the
continental regions next to these cold currents are dominated by deserts. The
Benguela Current, for example, is responsible for the formation of the Namib
Desert. Conversely, if the ocean is dominated by a warm current, such as in
the Gulf of Guinea off the coast of West Africa, the air becomes highly
saturated with water. As a result, countries like Cameroon receive more than
5,000 millimeters (200 inches) of rain per year.
The water vapour in the atmosphere forms clouds. These clouds are blown across the land, and forced upwards by hills or
    mountains, or by two air streams meeting and pushing them upwards. Cooler temperatures higher up cause the water
    vapour to condense and fall to the Earth as rain, snow, sleet, hail, or frost. This is called precipitation. Some of the
    falling water is intercepted directly by trees and plants. Much of it infiltrates into the soil and is drawn up through the
    roots of plants. This water helps the plants to grow, and any excess is drawn out of the leaves and back into the
    atmosphere by a process known as evapotranspiration.
Rainwater that is not used by plants runs through or over the surface of the soil until it reaches a river. Water that runs
    over the surface is called surface runoff. Through flow is water that moves through the soil, and water that infiltrates
    further to the water-table is called groundwater flow. Eventually the water in the river flows back into the sea and the
    cycle begins again.
The Human Effect on the Hydrological Cycle
Human beings play an important role in the hydrological cycle because they need large amounts of water to survive. Large
     reservoirs are constructed so that water can be pumped to big cities. Reservoir water is also used to create
     hydroelectric power. Every day people use many liters of water, which is then treated to remove dangerous materials
     before being returned to the rivers or sea. However, humans also contaminate the hydrological cycle, causing acid rain
     and river pollution. Acid rain is created by power stations and other industrial factories pumping waste material into
     the atmosphere, where it mixes with the moisture in the clouds.
Various chemical reactions take place in the atmosphere, so that when it rains the water is slightly acidic. Acid rain is
     responsible for killing large numbers of trees. Farmers treat their soil with fertilizers that contain chemicals. Although
     these chemicals help plants to grow, the chemicals themselves are dissolved by rainwater and end up in streams and
     rivers. Particularly harmful are nitrates, which accumulate in lakes where they cause the number of nutrients in the
     water to eutrophy.
As a result, the surface of the water becomes covered in a thick layer of algae, known as algal bloom, which removes
     dissolved oxygen from the water. Deprived of oxygen, the fish eventually die. Farmers also spray their crops with
     pesticides and herbicides, which may pollute groundwater before it enters rivers, and this also harms the fish.
     Farming the land can cause soil erosion. Rain hitting the bare soil is not intercepted first by plants, and there are no
     plant roots in the soil to bind it together, so the water runs off the surface into the river, carrying with it a layer of soil.
A clean supply of water is essential for healthy living. However, its uneven distribution throughout the world, combined
     with the careless and inefficient use of this valuable resource, means that while many people in developed countries
     have access to water 24 hours a day, approximately 1 billion, mostly in developing countries, struggle to find enough
     clean drinking water to survive. Around 80 countries currently face serious water shortages, and meanwhile world
     demand for fresh water grows yearly. Some countries are even in dispute over water resources. For example, Egypt is
     concerned that Sudan and Ethiopia will take possession of the Nile waters. For these reasons, and more, it is vitally
     important that water supplies are managed carefully for the future.

								
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