Chapter 17 Online Study Guide

Miners used canaries in coal mines as indicators of air quality because canaries are highly sensitive to toxic gases such as carbon monoxide and methane. These gases are often present in coal mines and can be deadly to humans. By observing the behavior of the canaries, miners could determine if the air was becoming dangerous and take necessary precautions to protect themselves. If the canary showed signs of distress or died, it was a clear warning sign for the miners to evacuate the area immediately.

Lichen is the correct answer because it is a mutualistic relationship between an alga and a fungus. The alga provides food through photosynthesis, while the fungus provides a protective structure and absorbs water and nutrients for both organisms. This symbiotic relationship benefits both the alga and the fungus, making it an example of mutualism.

Exposure to radon, a colorless radioactive gas, is a significant concern for indoor air pollution. It is particularly prevalent in houses with attached garages, as carbon monoxide from cars can seep into the house through door jams. Radon is a known carcinogen and can cause lung cancer. Therefore, radon is the correct answer to the question.

Nitrogen dioxide is responsible for the brownish haze in photochemical smog. When sunlight reacts with nitrogen oxides and volatile organic compounds (VOCs) emitted from vehicles, power plants, and industrial processes, it leads to the formation of nitrogen dioxide. This brown-air smog is a result of the chemical reactions between nitrogen dioxide and other pollutants in the atmosphere, creating a mixture of harmful gases and particles that contribute to air pollution and respiratory issues.

If 400 million Chinese drivers drive cars by 2050 as projected, the resulting photochemical smog could cover the entire western Pacific in ozone, extending to the United States. This suggests that the increase in car emissions from a large number of drivers would contribute to the formation of smog and ozone pollution, which could have far-reaching effects on air quality and public health.

The thermosphere is the topmost layer of our atmosphere. It is located above the mesosphere and stratosphere. This layer is characterized by extremely high temperatures and contains ionized gases. It is also where the auroras occur due to the interaction of solar particles with the Earth's magnetic field. The thermosphere plays a crucial role in protecting the Earth from harmful radiation and is home to the International Space Station.

The correct answer is 33%. On page 421, it discusses the percentage of different pollutants released from coal-burning power plants, including mercury. It states that 33% of the mercury released by humans comes from coal-burning power plants. This indicates that coal-burning power plants are a significant source of mercury pollution.

Photochemical smog is formed when sunlight reacts with pollutants like nitrogen oxides and volatile organic compounds. These pollutants are released from various sources such as vehicles, industries, and power plants. In Fort Worth, the problem with photochemical smog would be the worst in August. This is because August is typically a hot and sunny month, providing favorable conditions for the formation of photochemical smog. The intense sunlight and high temperatures accelerate the chemical reactions between pollutants, leading to the accumulation of smog in the atmosphere.

Rain and snow can actually reduce air pollution because they act as natural cleaners by washing away pollutants from the air. When rain or snow falls, it captures and removes particles and gases such as dust, pollen, and pollutants like sulfur dioxide and nitrogen oxides from the atmosphere. This process is known as wet deposition, and it helps to improve air quality by reducing the concentration of harmful substances in the air. Therefore, rain and snow are effective in reducing air pollution.

Both sulfur and nitrogen cycles contribute to acid rain. Acid rain is formed when sulfur dioxide (SO2) and nitrogen oxides (NOx) are released into the atmosphere from human activities such as burning fossil fuels. These gases react with water, oxygen, and other chemicals in the air to form sulfuric acid and nitric acid, which then fall to the ground as acid rain. Therefore, understanding the sulfur and nitrogen cycles is important in comprehending the causes and effects of acid rain.

The ozone layer is located in the stratosphere. This layer is situated above the troposphere and below the mesosphere. The ozone layer plays a crucial role in protecting the Earth by absorbing harmful ultraviolet radiation from the sun.

The four layers of the atmosphere are determined by temperature because as altitude increases, the temperature changes. The layers are divided based on these temperature variations. The first layer, the troposphere, is the lowest and has decreasing temperatures with altitude. The second layer, the stratosphere, has increasing temperatures due to the presence of the ozone layer. The third layer, the mesosphere, experiences decreasing temperatures again. Finally, the thermosphere, the outermost layer, has increasing temperatures due to the absorption of solar radiation. Therefore, temperature is the primary factor used to determine the layers of the atmosphere.