IBES&S Chapter 6 - intro to our atmosphere

1. What two layers of the atmosphere are most important to life?

Stratosphere and troposphere.

2. What 2 main gases make up our atmosphere (%)?

Oxygen and nitrogen.

3. What 2 abiotic factors influence climate the most?

Temperature and precipitation.

4. How do we measure the gases from our ancient atmosphere?

We can measure temperature both directly and indirectly. Also we can measure atmospheric gas concentration in bubbles trapped in ice. 

5. Describe (briefly) how temperature has changed in the past.

Before pants evolved to photosynthesis there was no free oxygen in the atmosphere. The average temperature on Earth was 20 degrees celsius and it went to 15.

6. Why is the greenhouse effect good?

It is a natural and necessary phenomenon that maintains a suitable temperature for living systems.

7. Explain how the greenhouse effect works.

It is caused by gases in the atmosphere reducing heat losses by radiation back into space. They trap heat energy that is reflected from the Earth's surface and reradiate some back to space and some to earth.

8. What happens to the solar radiation that reaches the Earth? (give percentages)

Nearly 50% is absorbed, scattered or reflected by the atmosphere and clouds before it reaches the surface of the Earth. Of the 55% of incoming solar radiation that reaches the Earth's surface, 4% is reflected and 51% absorbed. This is used in several processes including photosynthesis, heating the ground and seas, and evaporation. 

9. What are the major greenhouse gases?

Water vapour, carbon dioxide, and methane.

1. Where is most ozone found?

It is found in two layers of the atmosphere, the stratosphere and the troposphere.

2. What is the chemical formula ozone?

O₃

3. Describe the process of ozone forming and breaking apart again.

Under the influence of UV radiation, oxygen molecules are split into oxygen atoms. Oxygen atoms are extremely reactive, and can combine with an oxygen molecule to form ozone. Ozone can also absorb UV radiation and then splits into an oxygen molecule and oxygen atom. The oxygen atom can react with another ozone molecule, making two oxygen molecules.

4. What specific types of UV radiation does the ozone layer protect us from?

UV-C, UV-B, and UV-A.

5. What are some of the potential negative effects of UV radiation?

Cataracts, genetic mutations, skin cancer, and damage to living tissues.

6. What are some of the potential beneficial effect of UV radiation?

Heat and photosynthesis.

7. What are the most important ozone depleting substances?

Halogenated organic gases, chlorofluorocarbons, methyl bromide, and nitrogen oxides.

8. What are the uses/sources of CFCs?

Propellants in spray cans, plastic foam expanders, refrigerants.

9. Explain how CFCs deplete ozone. (Is this positive or negative feedback?)

With CFCs, the chlorine atoms can react with ozone, which results in ozone destruction. They can also react with oxygen atoms, thereby preventing ozone formation. One chlorine atom can thus destroy many molecules of ozone in a chain reaction with positive feedback.

10. Give some examples from each strategy to reduce ODS. (Replace, Regulate, Restore)

We can alter the human activity producing pollution by replacing gas-blown plastics, CFCs with CO2, propane, or air as propellant. We can regulate and reduce pollutants at the point of emission by capturing CFCs from scrap car air conditioner units and recovering/recycling CFCs from refrigerators and AC units. We can clean up and restore by adding ozone or removing chlorine from the stratosphere.

11. What is the Montreal Protocol?

It is an international agreement to phase out the production of ozone depleting substances. 

12. Was the Montreal Protocol a success? Explain.

Yes. Because it has accomplished the reduction of emissions of CfCs and other ozone depleting substances.

1. According to UNEP, what are 4 reasons that air pollution is problematic?

1 billion people are exposed to outdoor air pollutants per year. 1 million people die prematurely due to air pollution. 2% of GDP is lost by air pollution in MEDCs and 5%in LEDCs. Over 90% of our urban pollution in LEDCs comes from old motor vehicles which are poorly maintained. 

2. What are primary pollutants? Give some examples.

Carbon monoxide and dioxide. Urban hydrocarbons. Nitrogen oxides, sulfur dioxide, and particulate matter. 

3. What are secondary pollutants? Give some examples.

Tropospheric ozone, particulates from primary pollutants, and PANs. 

4. Describe how ozone is formed in the troposphere.

NO reacts with oxygen to form NO2. This contributes to urban haze. Hydrocarbons and carbon monoxide accelerate the formation of nitrogen oxide. Sunlight is absorbed and it breaks up into nitric oxide and oxygen atoms. The oxygen atoms subsequently react with oxygen molecules forming ozone. 

5. What are the possible effects of tropospheric ozone?

It can cause damage to cars, plants, humans, and materials/products. 

6. What processes lead to the formation of particulates?

Burning almost any organic material or fossil fuel releases small particulates of carbon and other substances. 

7. What are some of the dangers of particulates?

Our respiratory filters cannot filter them which can lead to asthma, lung cancer, and premature death. Many are carcinogenic. Agriculture areas by industry can cause crops to have a lower productivity. 

8. What is photochemical smog mostly composed of?

Mainly NO2 and ozone but also a mixture of primary and secondary pollutants. 

9. How does photochemical smog usually form in cities?

Mainly from motor vehicle exhausts. 

10. Why is smog usually at its maximum in the early afternoon even though most people drive in the morning?

This is due to the fact that the important smog causing reaction is a photochemical reaction, so it reaches its peak in the afternoon sun. 

11. What factors govern photochemical smog?

Local topography, climate, population density, and fossil fuel use.

12. Explain how “thermal inversions make things worse.”

It’s worse because on warmer days a warmer layer of air on top of the warm polluted air can cause this air rising, trapping the pollution at ground level. 

13. Give some examples from each strategy to reduce smog. (Replace, Regulate, Restore)

Consume less, burn less fossil fuels. Government regulation/taxation. Re-greening of cities, more trees, more plants.

1. Define an acid in terms of the pH scale.

Acids are chemicals that are able to give a hydrogen ion away. On the pH scale, 7 is neutral, below indicates acidity, and above indicates basic solutions. 

2. What is the pH of “normal rain”?

About 5.6.

3. Is acid deposition a primary or secondary pollutant? Explain.

It's a secondary pollutant because the primary pollutants can react to form secondary pollutants. 

4. What are the 2 main primary pollutants that lead to acid deposition?

Sulfur dioxide and nitrogen oxides.

5. What are some common sources of sulfur dioxide?

Naturally it is produced by volcanic eruptions and nitrogen oxides by lightning.

6. What are some common sources of Nitrogen oxides?

They are formed by reacting with oxygen and nitrogen from the air, which readily takes place at the high temperature during combustion of fossil fuels. 

7. What are some direct effects of acid deposition?

It can weaken tree growth, acid falling on lakes and ponds decreasing pH of the water and affecting aquatic organisms.

8. What are some indirect effects of acid deposition?

It can increase solubility of metal ions such as aluminium and can leach nutrients.

9. Describe how forests are affects by acid deposition.

Leaves and buds yellow. Can reduce growth and allows nutrients to leach out and be washed away. Symbiotic root microbes are killed and it reduces the availability of nutrients. Reduces ability of soil particles to hold on to nutrients. 

10. Describe how acid deposition relates to aluminum ions.

Acid depositions decrease the soils pH which makes aluminum more soluble. The aluminum is released from the soil and it eventually ends up in streams and rivers. In aquatic environments, fish and aquatic organisms are sensitive to aluminum in water. Fish productivity is decreased.

11. Describe how acid deposition relates to lichens.

They are sensitive to gaseous pollutants like sulfur dioxide and are used as indirect measures of pollution. These are indicator species of high levels of air pollution. As the distance from the source of pollutants increases more and more species are able to survive. 

12. Describe how acid deposition relates to soil fertility.

Acid deposition affects the soil by reducing the ability of soil particles to hold on to nutrients, which are then leached. It also inhibits nitrogen fixing bacteria and affects their ability to add nitrate ions to the soil.

13. Describe how acid deposition relates to buildings.

Limestone buildings and statues react with acid and simply dissolve. 

14. Describe how acid deposition relates to peat bogs.

Peat bogs have produced up to 40% less methane than before because of acid rain. This reduction in methane production reduces methane, a GHG in the atmosphere.

15. Describe how acid deposition relates to human health.

Dry acid deposition is in the form of small particles and these can penetrate into houses and our lungs. Premature deaths from lung disease such as asthma and bronchitis can result from this.

16. Give some examples from each strategy to reduce acid deposition. (Replace, Regulate, Restore)

Use low sulfur fuels, remove sulfur before burning, or burn mixed with limestone. Catalytic converters convert nitrous oxides back to nitrogen gas. Liming acidified lakes and rivers. 

17. Summarize Europe’s approach to solving this problem. Include information on the Convention on Long Range Transboundary air Pollution and the Sofia Convention.

Acid rain was becoming more of a concern with the negative effects on German forests and lake biodiversity. Un Convention on Long Range Transboundary Air Pollution was created which was modified and many agreed to cut sulfur emissions by 30% of 1980 levels by 1993. 30 countries adopted the Protocol on the Reduction of Sulfur Emissions which reduced emissions by 30%. Sofia convention reduced nitrogen oxides by 30% of 1987 levels by 1998. 27 countries signed up foto new protocol on Long range Transboundary Air Pollution to reduce and prevent air pollution.

18. Summarize The United States’ approach to solving this problem. Include information on the Clean Air Act.

The Clean Air Act target was to reduce sulfur dioxide emissions. Mostly affected coal-burning power stations in eastern states. Allowance trading scheme led to producers of acid deposition gases allocated allowances to emit an amount of sulphur dioxide. 

19. Summarize how the effects of acid deposition can be “neutralized” by…

    1. Liming Lakes

The pH of treated lakes is quickly raised but short-lived because of the acidic nature of the inflow of water. Liming only treats the symptoms and not the cause. Biodiversity was not immediately restored but the lime seemed to affect the nutrient balance as nutrients other than calcium were absent.

2. Reducing Emissions

Reducing the need for electricity, use of cars, developing more efficient or electric-powered cars and switching to alternative energy sources. Also biofuels and nuclear power generation will reduce SO2 and NOx emissions.

3. Pre-combustion Techniques

It aims to remove SO2 before the combustion. It can be obtained in several useful forms in which sulphur can be used in the chemical industry as gypsum, or as sulfur dioxide which can be used in the production of sulfuric acid.

4. End of pipe Measures

It removes the sulfur dioxide and nitrogen oxides from the waste gases. Waste gas scrubbers are intended to remove sulfur dioxide. The catalytic converter removes nitrogen oxides, together with other pollutants.