Acid rain is a popular term for the atmospheric deposition of acidified rain, snow, sleet, hail and particulates, as well as acidified fog and cloud water. The increased acidity of these depositions, primarily from sulfuric and nitric acids, is generated as a by-product of the combustion]] of fuels, especially in fossil fuel power plants. The heating of homes, electricity production, and driving vehicles all rely primarily on fossil fuel energy. When fossil fuels are burned, acid-forming nitrogen oxides and sulfur oxides are released to the atmosphere. These chemical compounds are transformed in the atmosphere, often traveling hundreds of kilometers from their original source, and then fall out on land and water surfaces as acid rain. As a result, air pollutants from power plants in the states of New Jersey or Michigan can impact pristine forests or lakes in undeveloped parts of the states of New Hampshire or Maine.

Acid rain in North America was discovered in 1963 in rain at the Hubbard Brook Experimental Forest (HBEF) that was some 100 times more acidic than unpolluted rain. Technology for reducing fossil fuel combustion emissions, such as scrubbers upstream of the tall flue gas stacks in power plants and other industrial facilities, catalytic converters on automobiles, and use of low-sulfur coal, have been employed to reduce emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx).

It should be noted that, although the examples in this article describe the North American situation, the nature and effects of acid rain are similar all over the world.

Terminology

The pH scale

The following definitions describe the technical terms that have a special meaning to the study or discussion of acid rain:

Acid rain: A broad term that includes both wet and dry deposition of material from the atmosphere which contain higher than normal amounts of acids (predominantly sulfuric acid and nitric acid).

Wet deposition: A term that refers to acidic rain, snow, fog, or mist that falls onto the ground from the atmosphere.

Dry deposition: A term that refers to the acids that may become incorporated into the dust and other particulates in the atmosphere and fall onto the ground, buildings, homes, cars, and trees. Dry deposition is washed from these surfaces by rainstorms, causing an increase in the acidity of the runoff water. Dry deposition is difficult to quantify but has been estimated to represent 20% to 80% of the total acid deposition, depending on location, season, and total rainfall.

Precipitation: A term that refers to either or both wet and dry deposition.

Acids: A term that refers to the acids found in acid rain. The atmosphere contains acid precursors (chemical forerunners) such as gaseous sulfur dioxide and nitrogen oxides that originate from natural sources as well as man-made (anthropogenic) sources. Those gases react with water and oxygen in the atmosphere to form mild (low concentration) solutions of sulfuric and nitric acids.

Acidity: The acidity of acid rain is measured using a scale called "pH". The lower is the pH of a substance, the higher is its acidity (i.e., the more acidic it is). As shown in the adjacent diagram, the pH scale is logarithmic and ranges from 0 (strongly acidic) to 14 (strongly alkaline or basic). Pure water has a pH of 7.0 which is considered to be "neutral", meaning that it is neither acidic or basic. However, normal rainfall is slightly acidic because carbon dioxide (CO2) in the atmosphere dissolves in the rain to form carbonic acid (H2CO3) which is weakly acidic and results in the rainfall having a pH of about 5.6.

The pH of precipitation (wet deposition) across the United States

Precipitation mechanism

How acid rain is formed in the atmosphere

The combustion of fossil fuels in power plants and other industrial plants produces combustion flue gases, containing acid-forming precursors such as sulfur dioxide and nitrogen oxides, that are emitted to the atmosphere. The combustion of hydrocarbon fuels in the engines of automotive vehicles, aircraft, trains and ships also produce exhaust emissions of acid-forming precursors such as nitrogen oxides and, in some cases, sulfur dioxide. In addition to those anthropogenic (man-made) sources, natural sources such as trees, forest fires, volcanoes, and geysers also emit acid-forming nitrogen oxides.

Those acid-forming precursors, sulfur dioxide and nitrogen oxides, are converted in the atmosphere by a complex series of reactions, into sulfuric acid and nitric acid. The adjacent diagram depicts the emission of acid-forming precursors into the atmosphere and their conversion into sulfuric and nitric acid as well as their subsequent wet and dry deposition.The emission of acid-forming precursors by natural sources led to the inference that precipitation in the pre-industrial atmosphere of forested regions had a pH of about 5.0 due only to the formation of carbonic acid from the CO2 in the atmosphere as per this reaction:

• water + carbon dioxide → carbonic acid
• H2O + CO2 → H2CO3

If that inference is true, then modern precipitation in the northeastern United States, with a pH ranging from about 4.5 to about 4.7 (see the above pH map), is two to three times more acidic than in pre-industrial times.

Effects of acid rain on surface water acidity

Acid deposition degrades the quality of surface water by increasing the acidity (i.e., lowering the pH) of the surface water. The degree of surface water acidification is an indicator of the potential harmful effects of acid rain on the biotic ecology as well as the plant life and soil of an entire watershed area.

Surface waters become acidic when the supply of acids from atmospheric deposition and other watershed processes exceeds the capacity of watershed soils and non-acidic drainage waters to neutralize them. When acidic surface waters drain into lakes and streams, it decreases their acid-neutralizing capacity (ANC). Surface waters are technically defined as being "acidic" if their acid neutralizing capacity is less than 0, which corresponds to having pH values less than about 5.2.

Aluminum leaches from silicate minerals which come in contact with low-pH waters and, hence, acidic surface waters increase the aluminum content of lakes and streams. While much of the aluminum present in surface waters is organically-bound and relatively non-toxic, certain inorganic species are highly toxic.

Acidity of the lakes and streams in the United States

The National Surface Water Survey (NSWS) in the United States documented the status and extent of chronic acidification during surveys conducted from 1984 through 1988 in acid-sensitive regions throughout the United States. Many lakes and streams examined in the NSWS suffer from chronic acidity, a condition in which water has a constant low pH level. The survey investigated the effects of acidic deposition in over 1,000 lakes larger than 4 hectares (about 10 acres) and in thousands of miles of streams believed to be sensitive to acidification. Of the lakes and streams surveyed, acid rain caused acidity in 75 percent of the acidic lakes and about 50 percent of the acidic streams. Several regions in the United States were identified as containing many of the surface waters sensitive to acidification. They include the Adirondacks and Catskills in New York state, the mid-Appalachian highlands along the east coast, the upper midwest, and mountainous areas of the western United States. In areas like the northeastern United States, where the soil-buffering capacity is poor, some lakes now have a pH value of less than 5.

Stream data from the HBEF reveal a number of long-term trends consistent with trends in lakes and streams across the northeastern United States. Specifically, the concentration of sulfate in streams at the HBEF declined 20 percent between 1963-1994. The pH of streams subsequently increased from 4.8 to 5.0. Although this represents a significant improvement in water quality, streams at the HBEF remain acidic compared to background conditions, estimated to be above 6.0. Moreover, the ANC of the lakes and streams in the HBEF has not improved significantly over the past thirty years.

Biologically-relevant surface water chemistry

The main cause for concern about surface water acidification in the United States and elsewhere is the potential for detrimental biological affects. Typically, there is concern for biological impact if the pH is less than 6. At low pH values, aluminum may be present at concentrations that are toxic to biota, including sensitive life stages of fish and invertebrates. Aluminum is normally a harmless component of silicate minerals in rocks and soils. However, when silicate minerals come in contact with low-pH waters, aluminum is leached into the waters.. While much of the aluminum present in surface waters is organically-bound and relatively non-toxic, certain inorganic species are highly toxic. The best indicator of recovery from the acidification of lakes and streams would be a decrease in the concentrations of inorganic monomeric aluminum, the most toxic form. Decreases in total aluminum would also suggest recovery, although the actual magnitude of the improvement in chemical conditions for biota would be unknown because such decreases would not disclose how much of the total aluminum decrease is due to inorganic versus organic forms of aluminum having been decreased.

Biological effects of acid rain

Effects on aquatic organisms

The pH tolerance of various aquatic species. Light blue areas indicate the pH levels which cannot be tolerated by the various species.

The biological effects of acidification have been demonstrated in laboratory whole-ecosystem acidification experiments and in field surveys. A number of species, especially of fish and macro-invertebrates, that commonly occur in surface waters cannot survive, reproduce or compete in acidic waters. Sensitive species may be lost even at moderate levels of acidity. As shown in the adjacent diagram depicting the pH tolerance of various aquatic life species, frogs have a high tolerance to increasing acidity (lower pH) and snails have a low tolerance to increasing acidity.

Decreases in pH and elevated concentrations of aluminum have reduced the species diversity and abundance of aquatic life in many streams and lakes of the northeastern United States. Fish have received most of the attention to date, but entire food chains are often adversely affected. In the Adirondacks, a significant positive relationship exists between the pH of lakes and the number of fish species present in those lakes. Surveys of 1,469 Adirondack lakes conducted in 1984 and 1987 show that 24 percent of lakes in this region do not support fish. These lakes had consistently lower pH and higher concentrations of aluminum than lakes that contained one or more species of fish. Even acid-tolerant fish species such as brook trout have been eliminated from some waters in the northeastern United States.

Trees destroyed by acid rain.

Effects on forest ecosystems

The 1990 National Acid Precipitation Assessment Program (NAPAP) report to Congress concluded there was insubstantial evidence that acid deposition had caused the decline of trees other than red spruce growing at high elevations.

More recent research shows that acid deposition has contributed to the decline of red spruce trees throughout the eastern United States and sugar maple trees in central and western Pennsylvania. Symptoms of tree decline include poor crown condition, reduced tree growth, and unusually high levels of tree mortality. Red spruce and sugar maple are the species that have been most intensively studied.

Red spruce trees: Since the 1960s, more than half of large canopy red spruce in the Adirondack Mountains of New York and the Green Mountains of Vermont and approximately one quarter of large canopy red spruce in the White Mountains of New Hampshire have died. Significant growth declines and winter injury to red spruce have been observed throughout its range. Acid deposition is the major cause of red spruce decline at high elevations in the northeastern United States. Red spruce decline occurs by both direct and indirect effects of acid deposition. Direct effects include the leaching of calcium from a tree’s leaves and needles, whereas indirect effects refer to changes in the underlying soil chemistry.

Red Spruce trees destroyed by acid rain and calcium depletion.

Recent research suggests that the decline of red spruce is linked to the leaching of calcium from cell membranes in spruce needles by acid rain. The loss of calcium renders the needles more susceptible to freezing damage, thereby reducing a tree’s tolerance to low temperatures and increasing the occurrence of winter injury and subsequent tree damage or death. In addition, elevated aluminum concentrations in the soil may limit the ability of red spruce to take up water and nutrients through its roots. Water and nutrient deficiencies can lower a tree’s tolerance to other environmental stresses and cause decline.

Sugar Maple trees: The decline of sugar maple has been studied in the eastern United States since the 1950s. Extensive mortality among sugar maples in Pennsylvania appears to have resulted from deficiencies of base cations, coupled with other stresses such as insect defoliation or drought. According to research studies, the probability of the loss of sugar maple crown vigor or the incidence of tree death increased on sites where supplies of calcium and magnesium in the soil and foliage were the lowest and stress from insect defoliation and/or drought was high. In northwestern and north central Pennsylvania, soils on the upper slopes of unglaciated sites contain low calcium and magnesium supplies as a result of the leaching of these elements by acid deposition combined with more than half a million years of weathering. Low levels of these base cations can cause a nutrient imbalance and reduce a tree’s ability to respond to stresses such as insect infestation and drought.

Trends in acidification

In the United States, governmental regulatory controls of the emissions of sulfur dioxide and nitrogen oxides, initiated in the 1970s and 1990s, have resulted in significantly reducing the acidification of soils, lakes and streams. Especially important is the "Acid Rain Program" in the U.S. Clean Air Act which has the goals of:

• lowering the annual emissions of sulfur dioxide to half of 1980 levels, capping them at 8.95 million tons starting in 2010 and
• lowering the annual emissions of nitrogen oxides to 2 million tons lower than the forecasted level for 2000, reducing annual emissions to a level of 6.1 million tons in 2000.

Over the past few decades:

• Ambient sulfur dioxide and sulfate levels are down more than 40 percent and 30 percent, respectively, in the eastern United States.
• Wet sulfate deposition has decreased about 40 percent in the northeastern United States and about 15 − 20 percent in the southeastern United States (see the two maps below).
• Some modest reductions in inorganic nitrogen deposition and wet nitrate concentrations have occurred in the Northeast and Mid-Atlantic regions of the United States, but other areas have not shown much improvement.

These trends indicate significant progress, but acid rain remains a significant long-term issue in the United States and elsewhere. Importantly, the emission and atmospheric deposition of base cations that help counteract acid deposition have declined significantly since the early 1960s with the enactment of air pollution controls on particulate matter, and the ability of ecosystems to neutralize acid deposition has decreased in some regions. Consequently, lakes, streams, and soils in many parts of the northeast are still acidic and exhibit signs of degradation linked to acid deposition.

The decrease in wet sulfate deposition between the periods of 1989 − 1991 and 2005 − 2007

Ecosystem recovery from acid deposition

Recovery from acid deposition requires decreases in acid gas emission which to reductions in acid deposition and allow chemical recovery. Chemical recovery is characterized by decreased concentrations of sulfate, nitrate, and aluminum in soils and surface waters. If sufficient, these reductions will eventually lead to increased pH and acid-neutralizing capacity (ANC), as well as higher concentrations of base cations. As chemical conditions improve, the potential for the second phase of ecosystem recovery, biological recovery, is greatly enhanced.

Biological recovery is likely to occur in stages, since not all organisms can recover at the same rate and may vary in their sensitivity to acid deposition. The current understanding of species’ responses to improvements in chemical conditions is incomplete, but research suggests that stream macro-invertebrates may recover relatively rapidly (i.e., within 3 years), while lake zooplankton may need a decade or more to fully re-establish. Fish populations in streams and lakes should recover in 5-10 years following the recovery of the macro-invertebrates and zooplankton which serve as food sources. It is possible that, with improved chemical conditions and the return of other members of the aquatic food chain, the stocking of streams and lakes could help to accelerate the recovery of fish.

Recovery of the forests and soils that have been acidified is more difficult to project than aquatic recovery. Given the life span of trees and the delay in the response of soil to decreases in acid deposition, it is reasonable to suggest that decades will be required for affected trees on sensitive sites to recover once chemical conditions in the soil are restored.

The time required for chemical recovery varies widely among ecosystems in the northeastern United States, and is primarily a function of:

• the historic rate of sulfur and nitrogen deposition
• the rate and magnitude of decreases in acid deposition
• the extent to which base cations such as calcium have been depleted from the soil
• the extent to which sulfur and nitrogen have accumulated in the soil and the rate at which they are released as deposition declines
• the weathering rate of the soil and underlying rock and the associated supply of base cations to the ecosystem
• the rate of atmospheric deposition of base cations

Affected areas

Acid rain symptoms have been reported in many locations worldwide.

Europe

During the latter half of the 20th century, pH values in the groundwater of Northern and Central Europe fell. The effect was especially pronounced in Finland, Sweden and Poland as shown in the map below:

Acid rain in Europe

Asia

Acid rain is an important issue in China and Japan. Given the area's generally increasing energy usage, the annual SO2 emissions in Asia could reach 110 million metric tonnes if action to reduce emission is not taken. Especially the escalating coal power production, mainly in China, is a major concern

ACID RAIN AND GEOLOGY : (Teacher's guide)

Level: Upper elementary to senior high

Anticipated Learning Outcomes

Students will become aware of acid rain, an important environmental problem.

Students will learn about the pH scale.

Students will determine the acidity of their local rain water.

Students will learn a little about the types of rocks in their state/region.

Students will discover how the types of rocks in an area can mitigate the effects of acid rain.

Background: Given on student handout.

Materials

Clean, plastic containers (the number needed depends on how many rock types you choose--see item 6). Don't use glass containers. Acidic solutions can leach bases from glass; the bases will neutralize the acid solution.

Acidified water. Collect some rain water, which will naturally be acidified. If you can't collect rain water, you can add sulfuric acid to distilled water to pH 4 or 5. Diluted hydrochloric acid (HCl) or vinegar, which contains acetic acid (CH3COOH), could be substituted for sulfuric acid. Substitution of hydrochloric acid or vinegar will not change the observed results.

Some method to measure pH (short-range pH paper that covers pH 3 to 8, or a pH meter).

Stirring rods (popsicle sticks or plastic spoons should suffice).

Plastic wrap.

Three or four kinds of rocks, preferably crushed. Crushing exposes more surface area to the solution and thus speeds up the reaction. Try to choose rocks that are common in your state or region. One rock type, however, must be limestone, dolomite, or marble.

Geologic map of your state/region (optional). If the rock types you choose can be keyed to a geologic map, the exercise will be more relevant.

Procedure: Given on student handout.

Results and Discussion

Only the limestone, dolomite, or marble will react. This assumes that none of the other rock types selected contains carbonate minerals like calcite or dolomite. When placed in the acidic solution, the calcite or dolomite will effervesce; the reaction will be more apparent with calcite than with dolomite, more apparent with a strong acid than a weak one. The bubbles that are produced are carbon dioxide (a gas), one of the products of the reaction. As the calcite or dolomite continues to react, the pH of the solution should approach 7.

This kind of reaction may be familiar to those students who bake. Many recipes call for vinegar (acetic acid) and baking soda (sodium bicarbonate, a base). Students may recall that when the two are mixed, they bubble. Just as in the case of limestone and acid, the reaction between vinegar and baking soda produces carbon dioxide as one of the products. The neutralizing effect of baking soda makes this common household product an effective remedy for "acid indigestion."

All rock types that do not contain calcite or dolomite (or any of the less common carbonate minerals that you should not have to worry about) should not react with the acid, and thus should not effervesce or cause a change in the pH.

The main goal of this exercise, therefore, is to show that lakes or rivers in areas with calcite-rich rocks should not be in danger of acidification, even if the rain is very acidic. For example, dolomite-rich rocks occur in southern Wisconsin, but not in the northern part of the state; only the lakes in the north are in danger of being acidified. Have the students study any geologic maps you might have to determine other danger areas.

Another interesting consequence of acid rain can be brought into the discussion. Many buildings and statues are constructed of limestone or marble; concrete also typically contains calcite. Such buildings and statues in acid rain areas are slowly deteriorating because the gypsum (one of the products of the reaction) is 100 times more soluble than calcite, and therefore gets washed away with the rain water. In Europe and Asia, some structures have been standing for tens of centuries. Will they survive long under the threat of acid rain?

         ACID RAIN AND GEOLOGY

                     (handout)

Background

1. The pH scale. Acidity of a solution is typically reported as a number that ranges from 0 to 14. The middle number, 7, designates a neutral solution, neither acidic nor basic. Numbers less than 7 refer to acidic solutions and higher numbers refer to basic solutions. The pH scale is not a linear scale; rather, it is logarithmic (base 10). For example, a change from 3 to 2 (a difference of just one) means that the resultant solution is ten times as acidic.
   
   
   The pH of some natural waters and common household solutions are depicted on the scale below. Note that unpolluted rain water is typically slightly acidic due to equilibration with atmospheric carbon dioxide (CO2).
   
   
   
2. Acid rain. Acid rain is a complex problem that requires an interdisciplinary approach in order to understand its generation and potential harm to the environment. Ecologists, chemists, geologists, and climatologists all study various aspects of the problem.
   
   
   Natural processes of respiration, decay, lightning-induced forest fires, and volcanic eruptions release numerous compounds into the atmosphere. During the past century, human activities have been responsible for ever larger amounts of these compounds into the atmosphere, primarily through the burning of fossil fuels (oil, natural gas, and coal). We refer to these compounds as pollutants if their concentrations exceed or approach the tolerance limits of organisms. Once in the atmosphere, many of these compounds, whether natural or human made, go through complex chemical reactions that produce new compounds. Two of these new compounds are sulfuric acid (H2SO4) and nitric acid (HNO3). When it rains (or snows), these two acids are washed out of the atmosphere and, in the process, acidify the rain water. Hence, rain water falling from a polluted atmosphere is more acidic, typically between pH 4.1 and 5.6.
   
   
   Coal- and oil-burning industries, exhaust from automobiles, and some smelting industries emit many sulfur and nitrogen oxides that greatly contribute to acid rain. Because of the ever increasing quantity of sulfur and nitrogen oxides, rain falling from polluted atmospheres is becoming more and more acidic. In the United States, most industry can be found in the eastern part of the Midwest and in the Northeast. Therefore, one might expect acid rain problems in those areas. Not so simple. Climatic patterns modify the distribution of the pollutants, and thus the distribution of acid rain. For example, areas downwind from some industries might be in greater danger of acid rain than the areas immediately surrounding the industry that produced the air pollutants.
   
   
   When the acid rain falls, it is incorporated in our rivers, lakes, and soil. The acids in the rain cause numerous complex chemical reactions to occur, thus further modifying the river, lake, or soil chemistry. Many organisms can not live in acidified waters. For example, game fish such as trout, bass, and perch do not thrive in water below pH 5. Thus, acid rain causes a decrease in diversity of organisms, an ecologic problem. Because the numbers and types of game fish decrease, there is an economic consequence also.
3. Effects of geology. If acid rain falls over a large area, why aren't all the lakes acidified? In part, the answer is geology. Some types of rocks can reduce (neutralize) the acidity of the rain, whereas other rocks have no effect. Calcite (CaCO3) and dolomite [CaMg(CO3)2] are two minerals that greatly mitigate the effects of acid rain; calcite and dolomite are the principal minerals that make up the rocks limestone and dolomite, respectively, as well as marble. For example, the case of sulfuric acid falling on limestone can be summarized by the following reaction:

H2SO4 + CaCO3 --> CaSO4.H2O + CO2

The sulfuric acid is neutralized as the mineral gypsum (CaSO4.H2O) and carbon dioxide are produced. Lakes located on, or rivers flowing through, limestone terrains will be neutralized; they will not suffer the consequences of acid rain. The same would be true in dolomite or marble terrains.

Procedure

1. Record selected rock types on the data sheet.
2. Add about 125 ml (1/2 cup) of acidified solution to each plastic container.
3. Record the pH of the starting solution above "time elapsed = 0" for each rock type on the data sheet.
4. Slowly add about two teaspoonfuls of crushed rock to the acidified solution and stir with a stirring rod.
5. Note any reactions or lack thereof.
6. Loosely cover each container with plastic wrap to prevent evaporation of the water.
7. At the end of the class period or at the end of the day (whichever best fits your school schedule), record the time elapsed and the pH.
8. Record time elapsed and the pH on a daily basis until the pH no longer changes.

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What To Know About Single Ply Roofing Systems

Here are the basics of single ply roofing systems. 

When you are talking about getting a single ply roof, there are quite a few things you are going to want to take into consideration. Although these roofs are chemically superior to other roofs, they also happen to be much thinner and susceptible to puncture should someone drop a hammer or throw a bottle up there. It is important that people weigh the pros and the cons of single ply roofs before deciding what is going to be the best option for their own building. 

The biggest downside to single ply roofs is that they can get punctured easily. If somebody is walking on the roof, or if somebody drops a hammer or a knife when they are on it, then you are going to have a leak. So that is a problem, especially with lower buildings where people can easily throw things up there. 

If you are building a one-story, fourplex home, where people might be climbing up on the roof and making a mess, then you definitely do not want to go with a single ply roof. In that case, you are going to want to choose a two or three ply built up roof or a modified roof simply because those options are physically stronger. There are multiple layers to those roofing styles, which means they can physically take more abuse before wearing out or causing leaks. 

Because single ply roofs are chemically superior, though, they can be a great alternative to restaurants that might have animal fats building up on the roof. The chemical properties of these roofs allow them to stand up well to things like animal fats or acid rain, along with inclement weather like wind, snow, or extreme sun. So all of those are reasons why a business would certainly choose a single ply roofing option. 

Another industry that commonly asks for a single ply roofing system is hospitals. If you are a hospital, you really dont want a hot tar roof material that is going to be seeping through and producing noxious fumes, especially once heat and temperature changes are taken into consideration. So instead, what you would be looking for in that type of situation is a single ply roof that is going to be chemically superior and cleaner at the same time. 

There are many grades of single ply roofs, and depending on which grade you have chosen, you may need to get your roofing maintenance done more or less often. Generally, you can get a good 10- or 15-, even 20-year manufacturer warranty on commercial projects with these roofs. 

Meanwhile, the average life span for a single ply roof is no more than 16 years on average. And after 16 years, people should plan on needing to do some re-roofing or some other type of major repair. One good aspect to single ply roofs, in this regard, is that the roofs lightness means that you can overlay the roof a lot of times before needing to tear it off entirely and start over. So people who have a single ply roofing system in place can just go over the areas where they need additional layers of roofing, which can be cost-effective. 

There are a million factors why you would or wouldnt choose a single ply roof, and all of the above reasons only start to touch on those factors. Most important, though, is that each homeowner or building owner knows the specific needs of his building, because that will be the biggest determination when choosing between a single ply or another roofing system.

Fossil Fuel Power Plants Have Provided Electricity For Years

Fossil Fuel Power Plants Have Been the Standard Electricity Production for Years

Though unpopular, fossil fuel power plants provide many countries of the world with electricity. These plants generate electricity through the burning of fossil fuels, such as oil or coal. How the fossil fuel is converted into electricity is a complicated process.

How Do Fossil Fuels Get Converted into Electricity?

The first step is that the fossil fuel must make its way from its source to the plant. Some plants are purposefully built next to a source of fossil fuel, but many plants need to have their fuel delivered. The fossil fuels can be delivered by truck, rail, or boat. Often delivery involves a combination of the three. Delivery methods for oil are generally the same as coal, with the exception that it can be transported by pipeline.

Once at the plant, the fossil fuel is burned to generate heat. This heat is used to heat water and create steam. The steam then rises through a turbine which transfers the thermal energy of the steam to mechanical energy. These turbine generators is attached to a generator, and the spinning of the turbine leads to the generation of electricity in the generator.

Waste Products of Fossil Fuel Power Plants

This is a streamlined description of how fossil fuel is turned into electricity. There is much more to how coal fired power plants work, however. For starters, there is the issue of waste products.

The waste from the burning of the fuel is the reason for much of the controversy surrounding fossil fuel power plants. Burning fossil fuel releases carbon dioxide into the atmosphere, which is believed to be a factor in global warming. Additionally, the burning of coal releases nitrogen oxides and sulfur dioxide into the air. When these mix with the atmosphere, they can cause acid rain. The U.S. and Europe have passed stricter emission laws to curb these effects.

Another hazard that has arisen is the effects of particulate matter. Particulate matter, often simply referred to as particulate, is tiny particles suspended in liquid or air. Previously, particulate was released when coal was burned. It would hang around in the air, and become inhaled. This was found to lead to asthma, chronic bronchitis, and airway obstruction. Because of these effects, various methods have been developed to reduce particulate.

The End of Fossil Fuel Power Plants?

While fossil fuel power plants have adapted to these changes, their days may be numbered. With the increased use of wind, solar, and nuclear power, fossil fuels are being phased out.

The Importance Of Rust Removal In The Home

While oxidation of metals may be a health hazard in many cases, for homeowners it is just plain ugly and detracts from the look of a property as well. It is a common problem, and one that many people simply accept as a fact of life. For those that choose to fight back, finding workable rust removal methods is the best option.

The success of a rust remover often depends on the extent of the problem. Different methods will produce varying degrees of success. The size and location of the items also impacts effectiveness.

What Causes Rust?

It comes as no surprise that this is a commonly encountered problem. In fact, it is difficult to imagine any home that has not dealt with this at one time or other.

It is basically a reaction of iron or steel to the presence of moisture. When the metal becomes wet, oxygen acts on the surface of the metal.

This produces what is known as iron oxide. This eats away at the metal, causing significant damage if allowed to go unchecked.

Despite the best efforts of homeowners oxidation is difficult to prevent. Leaking pipes, rain and any number of water sources can cause metal to become wet.

Realistically, it is impossible to protect metal at home from contact with water. This makes rust removal an important consideration for homeowners. It should be part of any home maintenance schedule.

How To Perform Rust Removal

In some cases, simply tossing out rusted items is the best solution. This is not an option for everyone. When valuable or irreplaceable items are involved, the decision to dump them is difficult. The cost of replacing these items makes it difficult to do. For others, the sentimental value of the piece is important.

Whatever the reason, many corroded items can be saved. If the problem is not extensive, some simple remedies might help, including:

* Soaking the items in vinegar: This may take some time and it is not feasible for large objects. After the rust is satisfactorily removed, oil should be applied to minimize the chance of the problem recurring. This method works best with light corrosion.

* Scrubbing with a cola-type soft drink: This popular drink contains an acid that can be used in dealing with corroded metal. For best results it is suggested that the area be scrubbed with aluminum foil after the soda is applied.

This solution is not recommended for complex or large jobs. Plus, working on hard to move items in small spaces isn't easy either.

* Commercial rust removers: these are products that can generally get rid of oxidation quickly and easily. While toxicity and skin reactions can occur, many newer products have eliminated these problems. Finding environmentally friendly commercial products is easy.

Rust removal is necessary to protect treasured items. It also helps maintain the desired look of the home. Using industrial strength removers is generally the method of choice for cleaning large pieces. There are products available that will deal with this common problem safely.