Acid RainWhat is acid rain? How does it form?Acid rain is no different to any other rain except that the water is acidic. Acid rain can have harmful affect on plants. It can also exist as fog, snow, dew and dry material. Distilled water is neutral but natural clean unpolluted rain is slightly acidic with a ph of 5.2. Any rain with a ph lower than this is said to be acidic. Acid rain mainly forms when there is a lot of sulfur, carbon or nitrogen dioxides/oxides in the air. Sulfur and nitrogen are the main causes of acid rain. Acid rain forms when molecules such as sulfur dioxide (SO2) combine with water vapour to form acids in this case sulfuric acid. This acid then lowers the ph of the rain making it acidic.
What are the causes of acid rain?Acid rain is mainly caused by many different industrial industries like coal power plants, metal ore refining and motor vehicles.
There are also minor natural causes that include volcanoes and rotting vegetation. But all the major causes mentioned are all produced by humans and produce sulfur. Once sulfur is in the air it forms sulfur dioxide (SO2). Sulfur dioxide can be naturally released into the air. For example volcanoes produce sulfur dioxide when active. When there is too much sulfur escaping into the air in a small area this can cause the sulfur dioxide to react with water and become sulfuric acid. The sulfuric acid then makes the rain acidic and harmful to the environment.
Another cause of acid rain is nitrogen oxide (NOx). Nitrogen oxide is caused by spark plugs in car engines. Nitrogen oxide forms when heat given off from a spark plug is sufficient for nitrogen and oxygen in the air form nitrogen oxide. Once the nitrogen monoxide gas escapes into the air it then changes to nitrogen dioxide. The nitrogen dioxide reacts with water and forms nitric acid. This form of pollution though has nowhere near as big effect as sulfur however.
What are the problems associated with acid rain?Acidic rain can cause plants to be burnt and die from the acidity. This can cause forests to die and kill all animals and insects that depend on the forest. The acid rain can as well cause the soil to be unfertile and to acidic for any thing to survive. It can also be irreversible. Acid rain can also get in to water way and kill all of the fish and other aquatic life in the river.
It is thought that emissions of sulfates may be linked with abnormally high mortality rates in humans. Studies have shown that acidic aerosols can cause impaired lung cleansing and lung irritation.
What measures are being taken to lessen the impact of acid rain?One of the methods to reduce the impact of acid rain is to catch the sulfur gas or waste from coal power plants and solidify the sulfur so it doesnÃÂt escape into the atmosphere. This method is called flue gas desulfurization. One of the flue gas desulfurization systems is a wet scrubber. A wet scrubber is reaction tower equipped with a fan that extracts hot smoke gases from a power plant into a tower. Lime slurry is injected into the tower to mix with the gases and combine with the sulfur dioxide. The compounds in the lime naturalise the sulfur dioxide. This produces sulfates. The waste or whatÃÂs ended with is some times sold to chemical companies as gypsum and is also just paced as landfill.
By changing our reliance of power plants and using renewable energy sources such solar and wind power acid rain can be reduced. Another way some countries have been trying to reduce acid rain is to tax the emission of acid causing substances.
There are international treaties between countries to reduce the amount of sulfur produced in the world and combat the problem of acid rain. This idea is currently being discussed in Australia to tax the emission of carbon.