Air Resources and Air Pollution Our Atmosphere

17_00CO.JPG Figure 17-00CO Title: View of Earth's atmosphere from space. Caption: Notes: Keywords: atmosphere, clouds

17_01.JPG Figure 17-01 Title: Earth's atmosphere. Caption: Earth's atmosphere consists mostly of nitrogen, secondarily of oxygen, and lastly of a mix of gases at dilute concentrations. Permanent gases are fixed in concentration. Variable gases vary in concentration as a result of either natural processes or human activities. Data from Ahrens, C. D. 2007. Meteorology today, 8th ed. Belmont, CA: Brooks/Cole. Notes: Keywords: atmosphere, gases, carbon dioxide, water vapor, methane, greenhouse gases, global warming, climates

STRUCTURE AND SCIENCE OF THE ATMOSPHERE The atmosphere consists of several layers with different temperatures, pressures, and compositions. Figure 19-2

Atmospheric pressure (millibars) Temperature Pressure Thermosphere Mesopause Heating via ozone Mesosphere Altitude (kilometers) Stratopause Figure 19.2 Natural capital: the earth’s atmosphere is a dynamic system that consists of four layers. The average temperature of the atmosphere varies with altitude (red line). Most UV radiation from the sun is absorbed by ozone (O3), found primarily in the stratosphere in the ozone layer 17–26 kilometers (10–16 miles) above sea level. QUESTION: How did living organisms lead to the formation of the ozone layer? Altitude (miles) Stratosphere Tropopause Ozone “layer” Heating from the earth Troposphere Pressure = 1,000 millibars at ground level (Sea level) Temperature (˚C) Fig. 19-2, p. 440

STRUCTURE AND SCIENCE OF THE ATMOSPHERE The atmosphere’s innermost layer (troposphere) is made up mostly of nitrogen and oxygen, with smaller amounts of water vapor and CO2. The ozone layer (stratosphere) filters out most of the sun’s UV radiation that is harmful to us and most other species.

17_02.JPG Figure 17-02 Title: Temperature profile of the atmosphere. Caption: Temperature drops with altitude in the troposphere, rises with altitude in the stratosphere, drops in the mesosphere, then rises again in the thermosphere. The tropopause separates the troposphere from the stratosphere. Ozone reaches a peak in a portion of the stratosphere, giving rise to the term ozone layer. Adapted from Jacobson, M. Z. 2002. Atmospheric pollution: History, science, and regulation. Cambridge: Cambridge University Press; Parson, E. A. 2003. Protecting the ozone layer: Science and strategy. Oxford: Oxford University Press. Notes: Keywords: atmosphere, temperatures

17_03.JPG Figure 17-03 Title: As one climbs higher through the atmosphere, gas molecules become less densely packed. Caption: As density decreases, so does atmospheric pressure. Because most air molecules lie low in the atmosphere, one needs to be only 5.5 km (3.4 mi) high to be above half the planet's air molecules. Adapted from Ahrens, C. D. 2007. Meteorology today, 8th ed. Belmont, CA: Brooks/Cole. Notes: Keywords: atmosphere, air pressures, atmospheric pressures

Core Case Study: When Is a Lichen Like a Canary? Lichens can warn us of bad air because they absorb it as a source of nourishment. Figure 19-1

Core Case Study: When Is a Lichen Like a Canary? Some lichen species are sensitive to specific air-polluting chemicals. After Chernobyl, more than 70,000 reindeer had to be killed because they ate highly radioactive lichens. Because lichens are widespread, long-lived, and anchored in place, they can help track pollution to its source.