Acid rain is a result of air pollution . when any type of fuel is burnt ,lots of different chemicals are produced . the smoke that comes from a fire or the fumes that come out of a car exhaust don't just contain the sooty grey particles that you can see- they also contains lots of invisible gases that can be even more harmful to our environment.
power stations, factories and cars all burn fuels and therefore they all produce polluting gases .some of these gases (especially nitrogen oxides and sulphure dioxide) react with the tiny droplets of water in clouds to form sulphuric and nitric acids . the rain from these clouds then falls as very weak acid -which is why it is known as 'acid rain'
OR,
Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low PH). It can have harmful effects on plants, aquatic animals and infrastructure. Acid rain is caused by emissions of sulphur dioxide and nitrogen oxide , which react with the water molecules in the atmosphere to produce acids.
Acid rain has been shown to have adverse impacts on forests, freshwaters and soils, killing insect and aquatic life-forms, causing paint to peel,corrosion of steel structures such as bridges, and weathering of stone buildings and statues as well as having impacts on human health.
RELATED TOPICS(CLICK)
- GLOBAL WARMING
- GREENHOUSE EFFECT
- ECOSYSTEM
- SUSTAINABILITY DEFINITION
- WASTE MANAGEMENT
- SUSTAINABILITY FORESTRY
- sewage treatment
acidity of acid rain
Acidity is measured using a scale called the pH scale. This scale goes from 0 to
14. 0 is the most acidic and 14 is the most alkaline (opposite of acidic).
Something with a pH value of 7, we call neutral, this means that it is neither acidic nor alkaline.
14. 0 is the most acidic and 14 is the most alkaline (opposite of acidic).
Something with a pH value of 7, we call neutral, this means that it is neither acidic nor alkaline.
Very strong acids will burn if they touch your skin and can even destroy metals. Acid rain is much, much weaker than this, never acidic enough to burn your skin.
Rain is always slightly acidic because it mixes with naturally occurring oxides in the air. Unpolluted rain would have a pH value of between 5 and 6. When the air becomes more polluted with nitrogen oxides and sulphur dioxide the acidity can increase to a pH value of 4. Some rain has even been recorded as being pH2.
Vinegar has a pH value of 2.2 and lemon juice has a value of pH2.3. Even the strongest recorded acid rain is only about as acidic as lemon juice or vinegar and we know that these don't harm us - so why do we worry about acid rain?
How is acid rain formed?
Acid rain is one of the consequences of air pollution. It occurs when emissions from factories, cars or heating boilers contact with the water in the atmosphere. These emissions contain nitrogen oxides, sulfur dioxide and sulfur trioxide, which when mixed with water become sulfurous acid, nitric acid and sulfuric acid. This process also occurs naturally through volcanic eruptions.
The Effects of Acid Rain on Ecosystems
An ecosystem is a community of plants, animals and other organisms along with their environment including the air, water and soil. Everything in an ecosystem is connected. If something harms one part of an ecosystem – one species of plant or animal, the soil or the water – it can have an impact on everything else.
effect on human
increased amount of nitrous oxide and sulphur dioxide in the air do contribute to heart
and lungs problems including asthma and bronchitis.
effect on human
increased amount of nitrous oxide and sulphur dioxide in the air do contribute to heart
and lungs problems including asthma and bronchitis.
Effects of Acid Rain on Fish and Wildlife
The ecological effects of acid rain are most clearly seen in aquatic environments, such as streams, lakes, and marshes where it can be harmful to fish and other wildlife. As it flows through the soil, acidic rain water can leach aluminum from soil clay particles and then flow into streams and lakes. The more acid that is introduced to the ecosystem, the more aluminum is released.
Some types of plants and animals are able to tolerate acidic waters and moderate amounts of aluminum. Others, however, are acid-sensitive and will be lost as the pH declines. Generally, the young of most species are more sensitive to environmental conditions than adults. At pH 5, most fish eggs cannot hatch. At lower pH levels, some adult fish die. Some acidic lakes have no fish. Even if a species of fish or animal can tolerate moderately acidic water, the animals or plants it eats might not. For example, frogs have a critical pH around 4, but the mayflies they eat are more sensitive and may not survive pH below 5.5.
Effects of Acid Rain on Plants and Trees
Dead or dying trees are a common sight in areas effected by acid rain. Acid rain leaches aluminum from the soil. That aluminum may be harmful to plants as well as animals. Acid rain also removes minerals and nutrients from the soil that trees need to grow.
At high elevations, acidic fog and clouds might strip nutrients from trees’ foliage, leaving them with brown or dead leaves and needles. The trees are then less able to absorb sunlight, which makes them weak and less able to withstand freezing temperatures.
It is thought that acid rain can cause trees to grow more slowly or even to die but scientists have found that it is not the only cause. The same amount of acid rain seems to have more effect in some areas than it does in others.
As acid rain falls on a forest it trickles through the leaves of the trees and runs down into the soil below. Some of it finds its way into streams and then on into rivers and lakes. Some types of soil can help to neutralise the acid - they have what is called a "buffering capacity".
Other soils are already slightly acidic and these are particularly susceptible to the effects of acid rain.
Acid rain can effect trees in several different ways, it may:
• dissolve and wash away the nutrients and minerals in the soil
which help the trees to grow.
which help the trees to grow.
• cause the release of harmful substances such as aluminium into the soil.
• wear away the waxy protective coating of leaves, damaging them
and preventing them from being able to photosynthesise properly.
and preventing them from being able to photosynthesise properly.
A combination of these effects weakens the trees which means that they can be more easily attacked by diseases and insects or injured by bad weather. It is not just trees that are affected by acid rain, other plants may also suffer.
Effects of Acid Rain on Materials
Not all acidic deposition is wet. Sometimes dust particles can become acidic as well, and this is called dry deposition. When acid rain and dry acidic particles fall to earth, the nitric and sulfuric acid that make the particles acidic can land on statues, buildings, and other manmade structures, and damage their surfaces. The acidic particles corrode metal and cause paint and stone to deteriorate more quickly. They also dirty the surfaces of buildings and other structures such as monuments.
The consequences of this damage can be costly:
- damaged materials that need to be repaired or replaced,
- increased maintenance costs, and
- loss of detail on stone and metal statues, monuments and tombstones.
ON Buildings
Every type of material will become eroded sooner or later by the effects of the climate. Water, wind, ice and snow all help in the erosion process but unfortunately, acid rain can help to make this natural process even quicker. Statues, buildings, vehicles, pipes and cables can all suffer. The worst affected are things made from limestone or sandstone as these types of rock are particularly susceptible and can be affected by air pollution in gaseous form as well as by acid rain.
ON Lakes and Rivers
It is in aquatic habitats that the effects of acid rain are most obvious. Acid rain runs off the land and ends up in streams, lakes and marshes - the rain also falls directly on these areas.
As the acidity of a lake increases, the water becomes clearer and the numbers of fish and other water animals decline. Some species of plant and animal are better able to survive in acidic water than others. Freshwater shrimps, snails, mussels are the most quickly affected by acidification followed by fish such as minnows, salmon and roach. The roe and fry (eggs and young) of the fish are the worst affected, the acidity of the water can cause deformity in young fish and can prevent eggs from hatching properly.
The acidity of the water does not just affect species directly, it also causes toxic substances like aluminium to be released into the water from the soil, harming fish and other aquatic animals.
Lakes, rivers and marshes each have their own fragile ecosystem with many different species of plants and animals all depending on one another to survive. If a species of fish disappears, the animals which feed on it will gradually disappear too. If the extinct fish used to feed on a particular species of large insect, that insect population will start to grow, this in turn will affect the smaller insects or plankton on which the larger insect feeds.
Solutions to Acid Rain
1).Cleaning up Exhaust Pipes and Smokestacks
Most of the electric power supporting the modern-day energy requirements comes from combusting fossil fuels such as oil, natural gas, and coal that generate nitrogen oxides (NOx) and sulfur dioxide (SO2) as the chief contributors to acid rain. Burning coal largely accounts for SO2 emissions while NOx emissions are mostly from fossil fuel combustions.
Washing coal, use of coal comprised of low sulfur, and use of devices known as “scrubbers” can provide technical solution to SO2 emissions. “Scrubbing” also called flue-gas desulfurization (FGD) typically work to chemically eliminate SO2 from the gases leaving smokestacks. It can eliminate up to 95% of SO2 gases. Power generation facilities can also shift to using fuels that emit much less SO2 such as natural gas instead of burning coal. These methods are simply called emission reduction strategies.
Similarly, NOx emissions from automobile fossil fuel combustions are mitigated upon by use of catalytic converters. Catalytic converters are fixed on the exhaust pipe system to reduce NOx emission. Improvement of gasoline that combusts cleaner is also a strategy for reducing emission of NOx gases.
2).Restoring Damaged Environments
Use of limestone or lime, a process called liming, is a practice that people can do to repair the damage caused by acid rain to lakes, rivers and brooks. Adding lime into acidic surface waters balances the acidity. It’s a process that has extensively been used, for instance in Sweden, to keep the water pH at optimum. Even though, liming is an expensive method and has to be done repeatedly. Furthermore, it only offers a short-term solution at the expense of solving the broader challenges of SO2 and NOx emissions and risks to human health. Nevertheless, it helps to restore and allow the survival of aquatic life forms by improving chronically acidified surface waters.
3).Alternative Energy Sources
Besides fossil fuels, there is a wide range of alternative energy sources that can generate electrical power. These include wind energy , geothermal energy,solar energy , hydropower, and nuclear power. Harnessing these energy sources can offer effective electrical power alternatives instead of using fossil fuels. Fuel cells, natural gas, and batteries can also substitute use of fossil fuel as cleaner energy sources. As of today, all energy sources have environmental and economic costs as well as benefits. The only solution is using sustainable energy that can protect the future.
4).Individual, National/State, and International Actions
Millions of people directly and indirectly contribute to SO2 and NOx emissions. Mitigation of this challenge requires individuals to be more informed about energy conservation and ways of reducing emissions such as: turning off lights or electrical appliances when not using them, use public transport , use energy efficient electrical appliances , and use of hybrid vehicles or those with low NOx emissions.
How to stop acid rain?
The only way to stop acid rain is to reduce emissions that cause it. This involves betting on renewable energy sources and reducing the use of fossil fuels in the industrial and automotive sector and in the daily life of every citizen.
- vehicles emission control reduces emissions of nitrogen oxides from motor vehicles .
- fluidized bed combustion also reduces the amount of sulfur emitted by power production .
- a wet scrubber is basically a reaction tower equipped with a fan that extracts hot smoke stack gases from a power plant into the tower.
- lime or limestone in slurry form is also injected into the tower to mix with the stack gases and combine with the sulphur dioxide present .
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