POLLUTION - ENERGY - The Handy Chemistry Answer Book (2014)

The Handy Chemistry Answer Book (2014)

ENERGY

POLLUTION

What are the potential dangers of nuclear energy?

The main risks associated with nuclear energy have to do with health hazards of radiation poisoning. This isn’t the same type of radiation we’re talking about with light and microwaves (that type is electromagnetic radiation). The radiation associated with nuclear energy involves subatomic particles, like neutrons, given off from nuclear decay processes. Exposure to this type of radiation can cause cancer or genetic defects, among other problems. Since the fission processes used to generate energy are normally well controlled, though, nuclear energy is generally one of the cleanest energy sources available. Nuclear reactors only become dangerous in the event of a meltdown or other disaster, but the chances of these happening are extremely small. Modern nuclear power plants are built with a series of fail-safes such that a series of multiple, extremely unlikely events would have to happen, one after another, for a meltdown to occur.

What pollutants do nuclear power plants generate?

Not many, unless something goes wrong. No greenhouse gases (like carbon dioxide) are generated in nuclear power plants, and each only produces roughly one cubic meter of waste per year. As long as this is properly taken care of, nuclear power plants are one of the cleanest forms of energy.

What pollutants do coal power plants generate?

Burning coal introduces pollutants such as nitrogen oxides, sulfur dioxide, and mercury into the atmosphere. A large amount of carbon dioxide, the principal pollutant implicated in global warming, is also produced by coal power plants. Aside from global warming, many of the pollutants from coal power plants are bad for human health and also cause smog, soot, and acid rain. The solid waste produced by burning coal can also be harmful to the environment. The ash from coal power plants is typically composed of about 5% pollutants or dangerous substances such as arsenic, cadmium, chromium, lead, and mercury. This can also cause pollution in water if it is not disposed of properly, and there have been many cases of water contamination caused by improper disposal of this ash.

Which energy sources produce the most CO2?

By far, it’s the fossil fuels: oil, gas, and coal. It’s the CO2 from all those combustion reactions that makes up about 96.5% of all the carbon dioxide emissions.

Which countries produce the most CO2?

Based on data for the year 2009, the top twenty-five, in order, are:

1. China

2. United States

3. India

4. Russia

5. Japan

6. Germany

7. Canada

8. South Korea

9. Iran

10.United Kingdom

11.Saudi Arabia

12.South Africa

13.Mexico

14.Brazil

15.Australia

16.Indonesia

17.Italy

18.France

19.Spain

20.Taiwan

21.Poland

22.Ukraine

23.Thailand

24.Turkey

25.Netherlands

How much CO2 production comes from automobiles?

According to the Environmental Protection Agency (EPA), the transportation industry as a whole accounts for 33% of all CO2 emissions in the U.S. Automobiles used for personal transportation account for 60% of this, or 20% of total U.S. CO2 emissions. The remainder comes from other sources of transportation, such as large diesel vehicles and airplanes burning jet fuel.

What is carbon sequestration?

Carbon sequestration and carbon capture are processes to remove carbon dioxide (CO2) from the atmosphere and store it. This is exactly what plants do when they convert CO2 into other molecules like sugars and proteins. Carbon dioxide can also react with water and limestone (CaCO3) to form calcium bicarbonate (Ca(HCO3)2) in an inorganic example of natural carbon sequestration. Generally, though, this term is used today to refer to man-made processes for removing CO2 from the atmosphere or for capturing it before it gets released (like from power plants). A number of approaches to long-term carbon dioxide storage are being, or have been, tried, including pumping the gas deep underground into natural rock formations, scrubbing the CO2 out from flue gas by reacting it with bases, or transforming the CO2 into other useful molecules for making polymers, just to name a few.

What causes smog?

Smog is caused by chemical reactions involving volatile organic chemicals and nitrogen oxides that take place in the presence of sunlight. These pollutants can come from a variety of sources, but in urban areas, a large quantity usually comes from motor vehicles. These are the reasons that smog often becomes a bigger problem when there is heavy traffic and lots of sunlight.

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Trees and other plants are seen here, damaged or killed by acid rain. Acid rain results when water in the atmosphere combines with chemicals like sulfur dioxide, acidifying rainwater.

What causes acid rain?

Similar to smog, acid rain is caused by chemical reactions of pollutants like sulfur dioxide and nitrogen oxides with oxygen and water in the air. The acidic pollutants formed in these reactions are the cause of acid rain. In addition to environmental pollution due to human activities, volcanic activity can also cause acid rain. Acid rain can be harmful to natural plant life, farm crops, animals, and marine life. It can also be damaging to buildings, depending on what materials were used in their construction.

What is the air quality index (AQI)?

The air quality index, or AQI, is a measure describing the amount of particulate matter found in the air. Since this value can vary significantly over short periods of time, the AQI is typically reported for a given city at least once per day. The higher the AQI value, the greater the associated health concerns. Since a few different measures exist out there for characterizing the air quality, we will spare you the details of exactly how the number is calculated. It is worth paying attention to the AQI when you are considering traveling or relocating to new places. Some large cities have developed major ongoing problems with their air quality, and looking at a city’s recent AQI history is a useful indicator of the air quality you can expect to find.

The table below summarizes relevant ranges of AQI values used in the United States and their health implications.

Air Quality Index

Level of Health Concern

Color (AQI)

0-50

Good

Green

51-100

Moderate

Yellow

101-150

Unhealthy for Sensitive Groups

Orange

151-200

Unhealthy

Red

201-300

Very Unhealthy

Purple

301-500

Hazardous

Maroon

What is the ozone layer and why is it so important?

Ozone has the chemical formula O3, and it is a gas that is naturally present in the Earth’s atmosphere. Most of the ozone in the atmosphere exists as part of a layer that sits a few miles above the ground. This is the ozone layer, and it serves to protect the Earth from a significant fraction of the potentially harmful UV light from the Sun. Depletion of the ozone layer means that more harmful UV light reaches the Earth’s surface. Ozone is also a greenhouse gas, which means that it also plays an important role in controlling the Earth’s climate.

What pollutants are dangerous to the ozone layer?

The pollutants principally responsible for depletion of the ozone are volatile halogenated organic compounds. The most well known among these are chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), which used to be used in virtually all air conditioning, refrigeration, and cooling systems. Another is methyl bromide, which is used commercially as an agricultural fumigant.