What is Acid Rain?
Acid rain, or acid deposition, is any form of precipitation (rain, snow, fog, hail or even dust) with acidic components, such as sulfuric or nitric acid that fall to the ground from the atmosphere.
Acid rain can be carried great distances in the atmosphere, not just between countries but also from continent to continent. The rain may sometimes fall many miles from the source of pollution.
Why is it important?
Acid rain may not be acidic enough to harm us directly through contact, however it can harm the forest and vegetation, damaging our lake and streams.
In Scandinavia, there are dead lakes, which are crystal clear and contain no living creatures or plant life. Many of Britain’s freshwater fish are threatened, there have been reports of deformed fish being hatched.
This will affect the food chain and eventually affect the human population. Acid rain can also cause damages to buildings and objects.
In a study from NUS, Singapore, twenty species of animals plentiful in the Bukit Timah Nature Reserve in the 1980s, including frogs, crabs and fish, are slowly being wiped out due to the pH value of the water in the reserve drop from ~6.5 to 4.4-4.7. This pH level is becoming too unhealthy for the marine species to survive.
There are many serious implications of acid rain on our society, hence, there is a need to study about acid rain and the concept of acidity behind it.
History:
In 1852, Robert Angus Smith was the first to show the relationship between acid rain and atmospheric pollution in Manchester, England. Though acidic rain was discovered in 1853, it was not until the late 1960s that scientists began widely observing and studying the phenomenon.
Herbert Bormann, together with a few scientists discovered acid rain in the Hubbard Brook Experimental Forest research in New Hampshire in 1971.
The concept of pH (Potential of Hydrogen) was first introduced by the Danish chemist Søren Peder Lauritz Sørensen at the Carlsberg Laboratory in 1909 and revised to the modern pH in 1924 to accommodate definitions and measurements in terms of electrochemical cells.
References:
http://projects.ncsu.edu/project/bio183de/Black/chemreview/chemreview_reading/acid_rain.html
http://www.straitstimes.com/print/Singapore/Story/STIStory_429394.html