High School
Teacher's Guide
to Craters of the Moon
Chapter Four:
Air Quality
Chapter Four:
Air Quality
The amended Clean Air Act of 1977 expresses our nation's desire to preserve, for its own sake, the ability to see long distance panoramas in our remaining wild lands, and to preserve ecosystems, plants and animals. The law established a program to prevent any significant deterioration of the air quality in areas of special scenic value, called "Class I" areas. The Craters of the Moon wilderness is one such area and thus enjoys the most stringent degree of air quality protection.
The National Park Service (NPS) must prevent deterioration in air quality beyond specified limits and protect monument resources from air pollution-related damage. Air pollution can impair park resources in numerous ways, including leaching nutrients from soil, acidification of water, damage to plants, discoloration and accelerated weathering of physical features, and reduced visibility. It is crucial that the airshed be managed to prevent irreversible damage to the entire ecosystem. Yet it is quite a different undertaking than managing other resources, since the source of problems often lies outside the park boundary.
After the passage of the 1977 Amendments to the Clean Air Act, the Park Service undertook an extensive program of monitoring air quality at selected sites in the National Park system. To most visitors, the air at Craters of the Moon seems fine; why monitor at all? Air quality monitoring provides an opportunity to detect and correct dangerous pollution trends before they harm fragile resources. Craters of the Moon is one site in a nationwide network which monitors acid deposition and ozone. Monument personnel also collect data on visibility, airborne particulates, airborne radioactivity, and operate a National Oceanic and Atmospheric Administration weather station. Weather data is important because weather directly affects air quality through moisture, clouds, and transport and dispersion of pollutants and particles. Monitoring serves two basic functions. Initially, it provides baseline information. Then ongoing monitoring allows scientists to document change from that baseline through time.
Let us examine the causes and potential impact of the various pollutants monitored here and what the data has revealed to date.
There are several emission sources in southern Idaho which may affect air quality at Craters of the Moon. The Idaho National Engineering Laboratory (INEL), a Department of Energy nuclear research center employing more than 10,000 people, lies 15 miles from the monument. The INEL has several facilities with air quality permits from the State of Idaho, 14 permits as of 1990. These facilities are operated in compliance with permit conditions. High level radioactive waste that contains acids is heated to convert the waste from liquid to solid. The acids are burned off and nitrogen oxides are released in a yellowish plume through a tall stack. Nitrogen oxides and sulfur dioxides may cause reduction in visibility and are precursors to acid deposition. Visibility-reducing particles and release of airborne radioactivity are of potential concern.
Large mineral and chemical plants are located in the Pocatello area, 60 miles southeast of the monument. In addition to general industrial air pollution, the fluorides emitted as a result of fertilizer production are a potential threat.
Mining practices and agricultural activities also degrade air quality. Burning stubble off fields is a common practice, and the dust generated by plowing fields and use of dirt roads may all result in lower visibility. Natural and man-caused wildfires also take their toll. Emissions from sources outside Idaho may also cross state borders and reach Craters of the Moon.
In order to appreciate and understand the geological phenomena for which the park was established, one must be able to clearly view the Great Rift, vast lava fields, and other geologic features. Therefore, good visibility is of primary importance at Craters of the Moon. The monument has some of the clearest air in the continental United States. On some fall days, you can see 243 miles, the theoretical maximum possible.
Two instruments measure visibility at Craters of the Moon. An automatic 35mm camera photographs Big Southern Butte daily at 9:00 a.m., noon, and 3:00 p.m. Scientists analyze these photos for the contrast between a dark distant object (Big Southern Butte) and the adjacent sky, assuming that the contrast will be higher when the air is clean and free of light-scattering particles. Based on their analysis, they assign a standard visual range, a measure of the clarity of the atmosphere, to each photo. In addition, a particulate sampler filters suspended particles from the air as a measure of how much dust, soot and other non-gaseous pollutants are present.
Standard visual range values at Craters of the Moon have decreased over the last 10 years. The degradation is significant because it detracts from the visitors' enjoyment of scenic vistas. This finding was a shock to the National Park Service, which had always considered Craters of the Moon to be a pristine airshed. While natural sources such as smoke from lightening- caused fires may be responsible for some of the deterioration, most of the air pollution at Craters of the Moon stems from people.
Biomonitoring measures the biological effects of air pollution on plants and animals. Research on several species has occurred at Craters of the Moon. In 1988, a botanist conducted a study of the lichens in the monument. He found slight indications of pollution damage in the campground area and along the state highway. Overall, however, he concluded that lichens show "no evidence of even moderate levels of air pollution" at Craters of the Moon.
What is Ozone?
Ozone is a form of oxygen and is the principal component of modern smog.
In nature, oxygen atoms tend to pair up in molecules of pure oxygen
known as O2; all animal life and, indirectly, most plant
life, requires O2 to live. Ozone (03) is also
oxygen, but in groups of three atoms per molecule. Ozone, formed from
emissions from forests fires and from lightning, occurs naturally in
very small amounts in the air we breathe. Normally, only one
O3 molecule is present for every 50,000,000 O2
molecules in our air (in scientific terms, .02 parts per million). At
this level, ozone is not harmful to life.
However, ozone can form in other ways and in dangerous amounts. The reactants necessary for the formation of ozone are also found in dry cleaning fluid, house paint, cleaning solvents, breweries, bakeries, petroleum refineries, furniture plants, and gas stations - all products or processes we deem necessary to our quality of life. More important, the fossil and organic fuels we burn - in our cars, power plants, factories, and refineries - generate hydrocarbons and nitrogen oxides, two of the key ingredients in the formation of ozone. These compounds rise into the lower atmospheric layer, or troposphere, where sunlight transforms them into ozone. In populated areas, ozone levels can rise to over ten times normal background levels. Such levels are dangerous to human, animal, and plant life. Nor are the dangers limited to cities; ozone continues to form as its ingredients drift downwind, and even higher concentrations may occur miles from the sources of the chemical precursors.
The Dangers of Ozone
In humans and animals, excessive ozone irritates the mucous membranes of
the respiratory system, and can reduce resistance to infection. It
aggravates chronic diseases such as bronchitis, asthma, and emphysema,
and may hasten death in persons already ill. Even healthy people can
suffer a temporary reduction in lung capacity after exposure to levels
of ozone currently considered safe. The effect can last up to a week,
and is worst for people such as athletes, who breathe the dangerous
chemical deep into their lungs.
In plants, ozone causes a wide spectrum of disease, decline, and even death. In 1984, a Congressional study determined that "Ozone causes about a 6 to 7 percent loss of U.S. agricultural productivity"; another source estimated the losses at one to two billion dollars annually. "So far, no monetary figure has been placed on ozone damage to forests, but the eventual price tag could be staggering", said the World Resources Institute in 1986.
Ozone is also known to damage paints, plastics, textiles, and some rubber products, though the exact extent is difficult to determine.
Since the installation of the Craters of the Moon ozone monitor in September of 1992, the national ambient air quality standard for ozone of .12 ppm level has not been exceeded here. At times, the equipment at Craters has recorded levels close to .08 ppm; recent evidence indicates that some sensitive plant species may exhibit injury at that level.
"Good" Ozone
Ironically, in another way ozone is beneficial. In a higher atmospheric
layer known as the stratosphere, ten to thirty miles above the
Earth's surface, ozone is naturally present in high concentrations in
what is called the ozone layer. At that altitude, ozone is formed
when intense sunlight strikes ordinary oxygen molecules; the ozone
produced is converted back into oxygen by yet more sunlight. This
continual process absorbs much of the sun's harmful radiation, thereby
protecting virtually all life on Earth.
The ozone layer has been seriously damaged by chlorofluorocarbons (CFCs) such as freon, which are widely used as refrigerants, aerosol propellants, in the manufacture of styrofoam, and in industrial cleaning processes. CFCs drift up into the stratosphere, decompose under ultraviolet (UV) radiation and release chlorine molecules that destroy enormous amounts of ozone; one molecule of chlorine can destroy up to 100,000 ozone molecules. This deterioration has created a "hole" in the ozone layer. The resulting increase in UV exposure at the Earth's surface may cause skin cancer and cataracts in humans as well as vegetation damage.
It would be helpful if the excess tropospheric ozone could drift up into the stratosphere and repair the depleted ozone layer. However, the stratosphere and the troposphere are separated by a natural barrier called the tropopause. Here the temperature difference between the atmospheric layers traps the excess ozone, much as temperature inversions sometimes trap smog over cities. The excess ozone cannot move upward through it.
What is Acid Rain?
All rainfall is by nature somewhat acidic. Decomposing organic matter,
the movement of the sea, geothermal activity and volcanic eruptions all
contribute to the accumulation of acidic chemicals in the atmosphere.
The principal factor, however, is atmospheric carbon dioxide, which
causes a slightly acidic rainfall even in the most pristine of
environments. Distilled water, with a pH of 7.0, is considered to be
neutral. Uncontaminated precipitation has a pH of about 5.7. In the
northeastern US it is not unusual to have rainfall with a pH of 4.0 --
which is 1000 times more acidic than distilled water! More than 200
lakes in the Adirondack Mountains of New York have reportedly become too
acidic to support fish life.
There is no doubt that man-made pollutants accelerate the acidification of rainfall. The burning of fossil fuels in power plants, paper mills, other industries, building heating, and vehicles produces sulfur dioxide (SO2) and nitrogen oxides (NOx). These pollutants combine with water in the atmosphere to form sulfuric acid (H2SO4) and nitric acid (HNO3). They often travel hundreds of miles before falling as acidic rain, snow, dust, or gas. All these wet and dry forms of acid deposition are known loosely as "acid rain."
Effects of Acid Rain
There is increasing concern that acid rain is causing serious,
irreversible changes in our environment. The environmental effects of
acid rain fall into four categories: aquatic, terrestrial, materials,
and human health. Since the impacts of acid rain are complex and
develop slowly, the extent of the impacts in these categories is
difficult to quantify.
Aquatic Effects
The adverse effects of acid rain are most apparent in aquatic systems. The most common impact appears to be on reproductive cycles. When exposed to acidic water, female fish and amphibians may fail to produce eggs or produce eggs that do not develop normally. Low pH levels also impair the health of fully developed organisms.Acid rain plays a role in the mobilization of toxic metals. These metals remain inert in the soil until acid rain moves through the ground. The acidity of this precipitation is capable of dissolving and "mobilizing" metals such as aluminum, manganese, and mercury. Transported by acid rain, these toxic metals can then accumulate in lakes and streams, where they threaten aquatic organisms.
The extent of damage acid rain causes depends on the total acidity deposited and the sensitivity of the area receiving it. An ecosystem's ability to resist change in pH is called its buffering capacity. The concentration of dissolved carbonates determines the alkalinity of the soil. Alkaline soils may neutralize acidic deposition. Calcareous rock (rock containing calcium, calcium carbonate, or lime) like limestone is very alkaline, buffering acid more readily than noncalcareous rock such as granite. In lakes that have little buffering capacity, acid rain may change the pH enough to kill sensitive plants and animals. Areas with acid-neutralizing compounds in the soil can experience years of acid rain without problems, whereas areas with little acid-buffering capacity are very vulnerable to damage from acid rain.
Terrestrial Effects
We know less about acid rain's effects on forests and crops than we do about effects on aquatic systems. The most extreme form of damage some have attributed to acid rain is the phenomenon known as "dieback". Dieback is a term applied to the unexplained death of whole sections of once-thriving forests. Dieback has occurred in areas of central Europe and the Appalachian Mountains of the US. Many scientists believe that air pollution is a contributing factor to this mortality. Pollutants may cause physiological changes in trees that lessen their resistance to diseases and to damage from freezing. There is, however, little direct evidence linking acid rain to forest dieback.Scientists do agree that acid rain can lead to other, less extreme effects on soil and forest systems. It can leach nutrients from soil and foliage while inhibiting photosynthesis. Acid rain can also kill certain essential microorganisms. The toxic metals it mobilizes when passing through the soil can be harmful not just to aquatic life, but to trees and crops as well.
Material Effects
Acid rain can also damage man-made materials; we are all familiar with photographs of statues that are losing their features and shape with acid rain cited as the culprit. The problem is far more than aesthetic. Building materials, too, can be degraded by acidity. Limestone, marble, carbonate-based paints, and galvanized steel all are eroded and weakened by the kind of dilute acids found in acid deposition. The Acropolis in Greece, the Coliseum in Italy, and the United States Capitol building, all are deteriorating due to the effects of air pollution.Since materials naturally deteriorate with time, it is difficult to differentiate acid rain damage from normal weathering, or to identify the damage caused by specific pollutants. Consequently, the precise role acid rain plays in the deterioration of materials is still unknown.
Human Health
So far, health problems resulting from direct contact with acid rain are unknown. Research is needed to confirm whether inhaling acidic particles in acid fog carries some health risk.
Is there Acid Rain at Craters of the Moon?
Since 1980, Craters of the Moon has operated a National Atmospheric
Deposition Program (NADP) site. The NADP is a national interagency
program for monitoring acid precipitation, with over 200 sites across
the country.
Once a week a park ranger collects a sample of the rain or snow which fell during the previous week. Precipitation falls into clean plastic containers which are covered to protect them from contamination during dry weather and uncovered automatically during rainfall. After measuring the acidity on a portion of the sample, the ranger seals the bucket and sends it to a central laboratory. There samples from throughout the country are analyzed. Scientists test them for pH and identify individual chemicals in each sample.
For 1989, the mean annual pH at the monument was 4.95 with a range of 4.01 to 6.59. If one accepts the definition that any reading below 5.6 constitutes acid rain, Craters of the Moon does sometimes experience precipitation that is slightly acidic. Precipitation data indicates no significant change in mean annual pH during 1982-7.
The Department of Energy operates an environmental surveillance program to monitor the direct (air and water) and indirect pathways (soil, foodstuffs, animals) by which radioactive materials from Idaho National Engineering Laboratory operations might reach the public.
Airborne particulate radioactivity is monitored by a network of 23 air samplers, 12 located within the INEL, seven near the Site boundary, and four at more distant locations like Craters of the Moon. With the exception of Craters of the Moon National Monument, the distant locations are sufficiently remote from the Site to ensure that detectable radioactivity is primarily due to natural background radiation or sources other than INEL operations. Craters of the Moon is close enough that radioactive particles from Site operations are occasionally detected at low concentrations. Public exposure to radiation from the INEL, through both direct and indirect pathways, is well below Environmental Protection Agency safety standards.
A pen is the most effective tool at your disposal to assure clean air for the future. Write to your government representatives at all levels and let them know how you feel about topical environmental issues. There are many public and private organizations dedicated to environmental concerns such as the reduction of air pollution, and any of them would be grateful for your interest. Some publish newsletters featuring articles about what you can do to help protect the environment.
Experts agree there is only one way to save the ozone layer - stop producing ozone depleting CFCs! This must be done as soon as possible. Because many CFCs remain in the stratosphere for up to 100 years, any action taken today to stop production of these chemicals will not result in reduced ozone depletion for decades. Environmentally safe styrofoam now exists. Pump-style dispensers have widely replaced aerosol sprays. Purchase these products and not their destructive counterparts. The use of freon in refrigerators, freezers and ice arenas continues to be a problem.
Don't forget the actions we can take in our daily lives that make a difference! Use car pools or mass transit where available. Otherwise, drive a fuel-efficient car and keep it properly tuned. Walk or ride a bicycle when traveling short distances. Find ways to make your home more energy-efficient. Store and dispose of hazardous materials properly. Select nature-friendly products when you shop. Reuse and recycle.
If a geographically isolated site like Craters of the Moon is beginning to be affected by air pollution, the time to take action to protect our air is now.
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