<Dd> H O (l) + H C O (aq) ⇌ H C O (aq) + H O (aq) </Dd> <P> However, unpolluted rain can also contain other chemicals which affect its pH (acidity level). A common example is nitric acid produced by electric discharge in the atmosphere such as lightning . Acid deposition as an environmental issue (discussed later in the article) would include additional acids other than H C O . </P> <P> The corrosive effect of polluted, acidic city air on limestone and marble was noted in the 17th century by John Evelyn, who remarked upon the poor condition of the Arundel marbles . Since the Industrial Revolution, emissions of sulfur dioxide and nitrogen oxides into the atmosphere have increased . In 1852, Robert Angus Smith was the first to show the relationship between acid rain and atmospheric pollution in Manchester, England . </P> <P> Though acidic rain was discovered in 1853, it was not until the late 1960s that scientists began widely observing and studying the phenomenon . The term "acid rain" was coined in 1872 by Robert Angus Smith . Canadian Harold Harvey was among the first to research a "dead" lake . Public awareness of acid rain in the U.S increased in the 1970s after The New York Times published reports from the Hubbard Brook Experimental Forest in New Hampshire of the myriad deleterious environmental effects shown to result from it . </P>

When was the term acid rain first used