THE SUBSTANCES THAT CAUSE ACID RAIN AND THE EFFETCS OF ACID RAIN

PREFACE

I have always loved science since I was a kid. I have always thought that dealing with chemicals would be really interesting, mysterious and also a little bit dangerous. This idea may have come from the movies that I watched. Not only mixing some chemicals, but also doing some calculations is absolutely fun! That’s why I love chemistry and the lessons. I am looking forward to coming school and join the lessons alive.

In this project I have learned lots of new things about acid rain. While doing this project’s research, I had a really great time. Unfortunately, “acid rain” is a very important topic that the whole world should be concerned about. By doing this project, I have learned how I can prevent acid rain a little bit with some changes in my life. I hope that everybody could take some precautions about it.

Suzan R. Hofstede, 2021

SUMMARY

Acid rain is a worldwide problem at the moment. As this problem is that huge, we should immediately take action in order to prevent or decrease the bad effects of acid rain.

To prevent the effects of acid rain, first of all we should know its meaning. Acid rain is mainly the result of pollution that we make. Air pollution and water pollution goes in a cycle and it is getting worse every moment.

In order to take some precautions we should also know what causes air pollution. We all know that day by day we use more fossil fuels, and the environment is getting dirtier. Not only fossil fuels, but also some chemicals cause those bad effects. The simpliest example is the smoke that comes from the fabrics and the houses, or the fumes that are released by cars and other transportation vehicles.

Lastly, the precations that we can take have a great importance. The easiest precaution is using more renewable energy and planting some flowers and trees. By doing these little and simple things, we can change the World really quick.

INTRODUCTION

By doing this project, I would like to learn some new information about acid rain. All the pupils are thought that “acid rain is a serious problem”, but when I think about what “acid rain” really is I cannot find a proper answer. Therefore I wanted to do a research about this interesting topic.

I want to learn the components that cause acid rain. While learning those components, I will also learn about how to write an equation in chemistry. As I love chemistry so much, I have always wanted to learn how those equations form since I was at the secondary school.

While doing this project my aim is to do a research about the acid rain. Mainly I will analyze what acid rain is, the causes of acid rain, the substances that cause acid rain, the effects of the acid rain on both humanity and environment, and lastly how we can prevent the acid rain.

WHAT IS ACID RAIN?

Acid rain is a type of rain that is unusually acidic. This aciditicy comes from the substances that humans use. When something is acidic, that thing should have high levels of hydrogen ions, which is usually called as a low pH. A low pH can be absolutely dangerous and harmful for both the environment and the humanity. Therefore it is really a serios problem that we all should be concerned about.

Acidity is measured with the pH scale. In total there are fourteen pH degrees. The middle point, which is number seven, symbolizes the neutral state. Distilled water is the water that the carbon dioxide has been removed from. Its pH degree is seven which means it is neutral. Between zero and seven the acidity is more than alkalineness. (The word “alkaline” is the opposite of the “acidic”.) A low pH is nearer to number zero. Between seven and fourteen, the alklineness increases.

Acid rain is the precipitation which has a pH degree about 5.2 or below. Generally it has pH is between 4.4 and 4.2. Normal rain’s pH degree is about 5.6 and 5.7. It can be understood that normal rain is also a little bit acidic. Carbon dioxide and water react with each other to form carbonic acid, which is a weak acid.

The following reaction symbolizes this statement: H2O (l) + CO2 (g) → H2C O3 (aq)

The more acidic components combine with water (rain), the lower pH the rain gets.

Acid rain can be also called as acid deposition or acid precipitation, as it does not always manifest itself in the form of rain. The precipitation can be in different types such as rain, snow, fog, hail or dust.

It is generraly caused by the over usage of fossil fuels which produces the emission of mostly sulfur dioxide (SO₂) and nitrogen oxides (NO and NO₂= NO_x). These components combine with other components and some other harmful components occur. For instance, sulfuric acid (H₂SO₄) and nitric acid (HNO₃).

The phrase “acid rain” was first used in 1852 by Robert Angus Smith. When we think about the time “1852”, we see that it was a time that was 168 years ago. Although it is such a long time before, there was a notion called “acid rain”. In the eighteenth century the first industrial revolution was began, which means the industry forms the “acid rain”. In 1960’s it was recognized that acid rain did not occur only in Europe and in North America, but everywhere. This means that it is a global problem. In my opinion, this emphasizes the importance and danger of acid rain.

THE CAUSES OF ACID RAIN

Acid rain can be wet or dry, both containing acidic substances. The image below shows the way that how acid rain occurs and gives harm to our environment.

· (1) The emissions of SO₂and NO_X are released into the air.

· (2) The pollutants combine with water and can be transported very long distances that we even cannot imagine. The wind can blow those pollutants over really long distances, so acid rain is not only a problem for who live close to these industrial sources, but everyone.

· (3) The precipitation of acid rain may not only ocur as rain, but also different forms like snow and fog.

· (4) The acid rain has a very huge effect on both humanity and especially the environment such as plants, aquatic animals and the infrastructure.

These dangerous and terrifying effects have some specific causes like the combustion of fossil fuels. The causes are generally because of the human activities. The usage of fossil fuels has been increasing day by day since the industrial revolution. This industrial revolution had not only occured in some specific areas like England and North America but everywhere. While these circumstances have been a part of our lives, we also should not ignore the dreadful effects on us.

The usage of vehicles and some heavy equipment such as cars, and trucks have also a big impact on the formation of the acid rain.

Electric power generators also have a big role in the creation of acid rain. While generating the combounds SO₂and NO_Xis released into the air.

Manufacturing and other industries also cause acid rain. Especially oil refineries have a huge impact on this problem.

The acid rain, of course, does not occur only by human activities. Also volcanoes release some gases while exploding which gives an enormous harm on environment by polluting the air. The lightning strikes also gives harm.

THE SUBSTANCES THAT CAUSE ACID RAIN

A rapid growth in population, a poorly planned urbanization, the usage of fossil fuels for domestic heating and to get energy for electricity, the heavy traffic, the volcanic eruptions and the industrial activities cause air pollution. Furthermore, while doing some tests about nuclear reactions, chemical and biological weapons and agricultural medicines are polluting the air and the environment. This air pollution occurs as a result of the reaction of some substances with water. Some of these compounds are:

1- Sulfur dioxide (SO₂),

2- Nitrogen dioxide (NO₂),

3- Hydrocarbons (It is an organic chemical compound composed of hydrogen and carbon atoms. They occur naturally and formed by crude oil, natural gas, coal and other energy sources. Simply, they are generated from the substances that are not renewable.),

Some industrial gases such as chlorine, ammonia (NH₃), carbon dioxide and methane.

These gases can be suspended in the air for two to seven days, can be reacted and can be carried for hundreds of kilometers away. Gases such as SO₂, SO₃, NO₂ and NO₃can combine with water molecules which is in the atmosphere and that water returns to the Earth as the acid rain.

By looking at a chart of “Mean acidifying emissions (air pollution) of different foods per 100g of protein”, it can be understood that air pollution has a huge impact on the acid rain. Besides, there are some other substances that cause the air pollution. While manufacturing and consuming these ingredients humans give harm to the environment once again.

Acid rain has two different types: wet acid rain and dry acid rain. There are two types of acid rain, dry and wet. Dry deposition refers to acidic gas and particles. About half of the acidity in the atmosphere returns to earth as dry deposition. Wind carries these acidic particles and gases to buildings, cars, homes, forests and ground. Wet deposition means rain, snow and dew. Both these types give a huge harm to the environment and both of them cause nearly from the same substances.

Some of the main reactions are:

NO₂ (g) + OH (g) → HNO₃ (g)

2SO₂ (g) + O₂ (g) g → 2SO₃ (g)

SO₂ (g) + OH (l) g →HOSO₂ (g)

2NO₂ (g) + H₂O (l) → HNO₃ (g) + HNO₂ (g)

SO₃ (g) + H₂O (l) g→ H₂ SO₄(l)

NO (g) + 1/2O₂ (g) → NO₂ (g)

HOSO₂ (g) + O₂ (g) → HO₂ (l) + SO₃ (g)

SO₃ (g) + H₂O (l) → H₂SO₄ (l)

[1]	This chart above describes the major causes of acid rain. It shows the percentages of the causes that create acid rain in the United States. The usage of coal, oil and natural gas - generally the burning of the fossil fuels - creates the substances that cause acid rain.

Mainly, the electic utilities compose the compound “SO₂”. In addition, the vehicles such as automobiles and trains has a great importance on the acid rain. For the formation of NO_Xgases, mostly the usage of vehicles and then the electric utilities play a big role. In the “other” section; manufacturing, generally industries, volcanic eruptions and the usage of chemical items such as deodorants are considered.

Here is another chart that is almost the same with the other one. In this chart, the industrial combustions are included as a serios problem. All in all, the human activities generate the acid rain.

[2]

THE EFFECTS OF ACID RAIN

As we have learned what acid rain is, and the substances that cause acid rain, now it is time to have a look at the effects of acid rain.

It generally has too many effects on both humanity and especially environment. It has a serios impact on the buildings, the water, the soil, the trees and the other creatures who live on Earth.

In this section, the effects of acid rain on water, on trees and forests, on buildings and other arquitectural items will be analyzed.

However, one does not need to worry about the effects of the acid rain and air pollution that much! In the next pages you will read about “how we can perevent these serious and dangerous effects of acid rain”. By carrying out those precautions, we can overcome these dreadful effects immediately.

THE EFFECTS ON WATER

Sulfur dioxide cools the atmosphere. Therefore, it is not the main cause of the climate change. Nitrogen oxides has also an impact on the formation of the ozone layer. Next to their positive effects on the environment, they also have some adverse effects on the environment and the human health.

For instance, both these gases cause some health problems such as the irritation of the eyes and asthma. Not only human health is affected by them, but also the water and the ecosystem inside the water are impacted.

The aquatic habitates are the most effected places by the acid rain. Day by day, the acidity of the lakes and the rivers increases and the number of animals that inhabitate decreases. Some types of plants and animals are however able to survive in these conditions. Snails and shrimps are the most affected animals in that ecosystem. Sometimes the acidity does not affect directly, but the release of some substances, such as aluminium, affects much more seriously. Another serious problem arises when some species become extinct, as a result of which the other species will also become extincted as the ecosystem malfunctions.

When limestone is added to water, it neutralizes the water. This process is called “liming”. By using this technique, we can prevent and reduce some of the dreadful effects of acid rain on water.

THE EFFECTS ON TREES AND FORESTS

It is believed that the acid rain decreases the speed of the growth of the trees. Sometimes the acid rain can cause their death which is as serious as the effects on water, for the ecosystems. Trees can be affected in different ways. When some of the minerals and nutrients in the soil are lost, then the trees cannot grow. Some harmful substances can be released to the soil and can cause the death of the trees. Sometimes the trees can lose their ability to do photosynthesis and can be damaged very seriously.

Acid rain does not only affect the trees but also the soil and other agricultural products. Usually, when the soil is acidic, then the water also gets affected by and becomes acidic. As one can consider, when ecosystem is damaged, this will harm every organism which live there.

Besides, there are some types of soil that can neutrilize the acid. This quality is called as the “buffering capacity”. Some of the soil types are sensitive to the acid rain because they may already be a little bit acidic.

THE EFFECTS ON BULDINGS AND OTHER ARCHITECTURAL ITEMS

Acid rain can also damage some buildings, sculpture, historic buildings and statues. The damage in these constructions is mostly seen when the material of the buildings are limestone and/or marble (calcium carbonate).

Acid rain does not only affect calcium carbonate, but also iron, steel, copper and bronze. One may think that these materials can also affected by the environmental issues such as wind, water, snow and ice. That is absolutely correct! However, when acid rain also become included in these groups, the process becomes much more progressive than usual.

Nearly everything around us suffer from the acid rain such as the buildings, the statues and even the vehicles! The vehicles, first cause these problems and then they get affected by them in turn. As everybody can guess, the worstly affected things are made from limestone and sandstone.

Some real life examples are the “Taj Mahal” and the “Statue of Liberty”.

The Statue of Liberty is made of copper and it is oxidated from acid rain. Fortunately, it is becoming greener and greener.

Taj Mahal is also affected by acid rain very seriously. In India, the industries release many substances into the air and this affects this gorgeous construction. People also use lots of coal and firewood in that area and this increases the acid rain. The acid rain reactes with calcium carbonate (marble), the material of Taj Mahal as the following equation:

CaCO₃ + H₂SO₄→ CaSO₄+ H₂O + CO₂

HOW CAN WE PREVENT ACID RAIN?

As the effects of the acid rain is very harmful to both ecosystems and the humanity, we should start taking some precautions.

The first precation is the reduction of the emissions. Unfortunately, the usage of fossil fuels is increasing as it is the cheapset energy source. But, if we start using the “renewable energy sources” then we can prevent many things, before some serious effects hit Earth.

Also the governments should take some precautions and spare some budget on this situation. If we can control and reduce the air pollution, the ecosystems will not be affected by the acid rain and can get better in a few years.

As I mentioned before, sulphur can be cleaned from the water with limestone. By using the “liming” technique we can reduce the water acidity and the water pollution. Some filters should be used in the factory chimneys. This will absolutely decrease the air pollution.

Instead of using the motorvehicles we can walk or cycle to our schools or jobs. Both the environment and the humanity will win! In addition, we will be able to do sports in our daily life as a routine and the pollution will be decreased.

All in all, there are lots of things that we can do to prevent the acid rain.

[3]

[4]

Here is a graph about the emissions that are decreased after the acception of several agreements and protocols in the United States (This graph is numbered as 23). After the Second World War, there was a huge increase in Europe and North America. The emissions, the power stations and the vehicles are being controlled, in order to reduce the air pollution and the acid rain. Unfortunately, the air pollution and the acid rain are increasing in the areas where intensive agriculture is done. In the second graph which is numbered as 26, we can evaluate that the amount of emissions has significantly decreased in both North America and Europe. The H⁺ concentration has been reduced about 86% in the United States between the mid-1960s and 2016. Unfortunately, the recovery of the ecosystems is getting slower.

CONCLUSION

Acid rain is a huge problem that each continent has been affected by seriously. Acid rain is a type of rain that is unusually acidic.

It is generraly caused by the over usage of fossil fuels which produces the emission of mostly sulfur dioxide (SO₂) and nitrogen oxides (NO and NO₂= NO_x). These components combine with other components and some other harmful components are produced, such as sulfuric acid (H₂SO₄) and nitric acid (HNO₃).

Mostly the human activities cause the acid rain but some natural events such as volcanic eruptions and the effects of lightnings can cause the acid rain.

The acid rain gives lots of damages and harm to the environment and human-made things. For instance, the water such as lakes and rivers, the soil, the trees, some sculptures and eventually all species are affected adversely by the acid rain.

All in all, if we reduce the usage of non-renewable energy then the acid rain may be prevented.

Suzan R. Hofstede, 2021