Acid Rain

One dilemma common to many environmental issues is knowing not only if, but when, to act. Both the global warming and ozone problems illustrate this dilemma. If such problems really do exist, early aggressive action is highly desirable. If they do not exist, huge social and economic losses can be sustained in dealing with what may turn out to be non-problems. A third atmospheric problem that presents this kind of dilemma involves acid precipitation.

The term acid precipitation refers to rain, snow, sleet, hail. or any other form of precipitation that is significantly more acidic than normal. The form of acid precipitation about which we hear most commonly is acid rain.

Water that falls to the earth as rain is often thought of as "absolutely pure." This is not quite accurate. As water droplets fall, they dissolve various solids, liquids, and gases found in the air. Carbon dioxide, for example. is a normal component of the air that is fairly soluble in water. Rainwater often dissolves measurable amounts of carbon dioxide as it falls to the ground.

The substances absorbed by rainwater from pure, clean air do not pollute it in any appreciable way. Carbon dioxide dissolved in water does it no harm. In fact, carbon dioxide improves the flavor of drinking water. Problems arise, however, when rain falls through an atmosphere that contains harmful pollutants. Examples of such pollutants include those produced by home heating systems, industrial factories, and power-generating plants. Among other things, these pollutants include nitrogen and sulfur oxides, formed during the combustion of coal. When dissolved by raindrops, these oxides react with water and form nitric and sulfuric acids.

As with most pollution problems, relatively small concentrations of these acids in rainwater tend to result in only small problems for the environment. The growth of some organisms may actually be promoted by a mildly acidic condition. The difficulty arises when the level of nitrogen and sulfur oxides in the air increases dramatically. And this is just what may be happening as our nation switches from the use of natural gas and petroleum to coal as a source of power.

From the early 1950's to the late 1970's, gas and oil were the fuels most widely used in commercial, industrial, and power-generating plants. Increasing shortages and higher prices for these fuels made it necessary for many of these plants to shift over to coal as a source of energy. As this change accelerated, the concentrations of nitrogen and sulfur oxides which were produced during the combustion of coal (a problem of minor concern with gas and oil) began to rise, Simultaneously, the acid concentrations of rainfalls also began to increase.

Following a familiar pattern, it was usually not the geographical area in which nitrogen and sulfur oxides were produced that experienced the effects of acid rains. It was (and is) the areas far beyond them. The reason for this is easy to understand. Nitrogen and sulfur oxides which are released from smokestacks are carried high into the atmosphere, then dispersed over the countryside (usually eastward) by prevailing winds. They continue drifting from their point of origin until a rainfall washes them out of the air and onto the ground.

Studies carried out in the early 1980's showed rainfalls in parts of North America and Western Europe to be as acidic as lemon juice or vinegar and, in some cases, as acidic as battery acid!

Needless to say. rainwater of this acidity is not very healthy for an environment. Aquatic plants and animals cannot survive large changes in acidity, and increases in acid rain have meant extinction for some populations of water plants, insects, frogs, salamanders, and freshwater fish. Indeed, some forms of rocks, like limestone and marble, are also dissolved by acid rain.

The solution to acid rain problems is not a simple one. As power plants in Canada and the American Midwest change over to coal-fired systems, lakes in New England and Canada sicken and die at an accelerating rate. Like the issues of cross-border pollution discussed above, problems of acid rain have become interstate and international in their scope and can be resolved only by the interaction of many governmental and private agencies.

Many experts would agree with the description of acid rain given so far. But how serious is this problem? Some authorities feel the environmental damage caused by acid rain is one of the most severe problems faced in the United States, Canada, and Western Europe. They suggest that many lakes and forests and the animals that live in them are being destroyed. They recommend immediate and aggressive legislation to cut down on the emissions that result in acid rain.

Other observers do not share this sense of urgency. For example, the administration of President Ronald Reagan continually expressed the view that too little was known about the cause, nature, and effect of acid rain to justify national legislation. Reagan's policy was to ask for further studies on the issue.

Important support for this position was provided in a 1989 report of the National Acid Precipitation Assessment Program (NAPAP). This report cost $500 million, reviewed hundreds of research studies, and took nearly a decade to complete. It concluded that "acid rain is a problem, but it is not the extreme problem that is sometimes reported in the media."

Some authorities have pointed out the political and economic significance of the NAPAP findings. If acid rain recommendations before Congress at the time the study was issued had been passed, they say, industries would have had to spend $4 billion for new emission control equipment. In addition, 16,030 miners would have lost their jobs. A newsletter of the Chemical Manufacturers Association commented on this turn of events. "If the NAPAP report is to be believed," it said, "those jobs will be sacrificed without achieving significant gains in environmental quality."

The Buck Stops Here

You have owned a cottage on Lake Shiawanassee in eastern Canada for ten years. Over the past two summers, you and other summer residents are becoming increasingly concerned about the condition of the lake. The wilderness area you know and love appears to be changing. These changes are neither sudden nor dramatic. But for Canadians and Americans alike who have made the lake their vacation home for many years, the indications are becoming hard to ignore. Fish are dying more rapidly than you can remember, and the lake itself has taken on that beautiful silvery sheen which, despite Its beauty, is a sign of high acidity. A neighbor reports to you that a local chemist has measured the pH of the lake as 5.5. You and she decide that "something has to be done" to save the lake. What is that "something"?

Your first task is to become as well informed as possible on the current status of the acid rain problem. Decide how important you think it is on an (1) international, (2) national, and (3) local level. If you decide that acid rain is an issue that requires the attention of the U.S. Congress, the Canadian Parliament, or some other national body, outline the specific actions you think should take place. You might draw up a model bill that contains your recommendations.

If you think acid rain is not an international or national problem, decide what you think you can or should do, at a local level, to protect Lake Shiawanassee.

created by: Debbie Anholt, anholt@lclark.edu
updated: May 9, 2000