1. Guided Notes about Air Resources
Chapter 25, Section 3

2. 1. Air contains substances that all organisms need to survive, including nitrogen, oxygen, carbon dioxide, hydrogen, methane, and ozone.

3. 2. Early life forms in the oceans used carbon dioxide during photosynthesis and released oxygen and water vapor. Over time, oxygen built up to levels that allowed the evolution of organisms that required oxygen for life processes.

4. Describe the balanced gas exchange of the Earth’s atmosphere:
Volcanic eruptions release various gases and dust particles into the atmosphere
Photosynthetic organisms take in carbon dioxide and release oxygen
Other organisms take in oxygen and release carbon dioxide

5. 4. The human alteration of the carbon cycle has the potential to change global climate and therefore the environments of food-producing regions.

6. 5. By burning fossil fuels and using fertilizers that contain nitrogen, humans release about three times as much nitrogen oxide and ammonia gas into the atmosphere as do the natural processes of the nitrogen cycle.

7. 6. Nitrogen oxides are converted to nitric acid, which returns to Earth in acid precipitation.

8. 7. Human activities also release sulfur into the atmosphere when coal and oil are burned to produce electricity. Sulfur in the atmosphere is converted to sulfuric acid.

9. 8. Air pollution results when pollutants in air occur in quantities that become harmful to human health and the health of the environment.

10. 9. The single largest source of air pollution in the U. S
9. The single largest source of air pollution in the U.S. is the exhaust from motor vehicles that burn fossil fuels in the form of gasoline.

11. 10. Carbon monoxide interferes with the body’s ability to absorb oxygen and causes headaches, chest pains, and nausea.

12. 11. Some pollutants undergo photochemical changes that are triggered by reactions with ultraviolet (UV) radiation. An example is photochemical smog, which forms when a mixture of nitrogen oxides and volatile organic compounds interact under the influence of sunlight.

13. 12. When 20% of the occupants of a building experience symptoms caused by indoor air pollutants, the building is said to be “sick”. New buildings are more likely to be “sick” because they are more airtight, in order to keep heating and cooling costs lower.

14. 13. Usually radon gas seeps upward through the soil and is released into the atmosphere, where it is diluted to harmless levels.

15. 14. When buildings are constructed with hollow concrete blocks, or if they have cracks in their foundations, radon gas can enter and build up to high levels indoors.