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AIR


Click on the links below to view specific sections of the sample material:

OVERVIEW

As with water, air is an essential requirement for life on Earth and by extension, critical for human
society. The atmosphere is a complex, dynamic and inherently unstable system, and one that is
constantly changing in time and space. To understand the impact of human activities on the
atmosphere it is useful to consider the basic principles of the system since these help to
explain the relationship between the atmosphere and the water, land and life of the globe.

Chapter 2 identified some of the key characteristics of the atmosphere, particularly those relevant for an understanding of human impacts. The nature of the atmosphere is changeable over time due to natural drivers, but it is also true that human activity has created change. Some of the most important changes have been in relation to our influence on the chemical composition of the
atmosphere, and this chapter will explore these elements in detail.


LEARNING OUTCOMES

After reading this chapter, you should be able to build on the ideas about the atmosphere in
Chapter 2 to better appreciate what the atmosphere is and how it works as well some of
the ways in which humans interact with it. In particular:

• Energy and the atmosphere – how and why air moves
• Pollutants and the atmosphere – sources, characteristics and impacts
• A number of key environmental issues primarily associated with the atmosphere – acidification, air pollution and climate change.
  

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SUMMARY

This chapter continued from the introduction to the atmosphere given in Chapter 2 and considered the processes of movement in the atmosphere. Since the troposphere is where most of the impacts of human activity are felt, at least initially, this was the focus of the discussion. The chapter went on to consider trends in concentrations associated with different constituents of the lower atmosphere. The sources, trends and characteristics of greenhouses gases in terms
of climate change, and reactive species in terms of urban pollution and acidification, were presented in some detail. The chapter ended with a broader consideration of these environmental issues, looking at air quality across the globe’s megacities and the likely impacts of climate change.

QUESTIONS

1. Describe the structure of the atmosphere.     How does this help with the notion that     pollution is just matter out of place? 5. Using the Global Sulfur Emissions      Database, plot a chart demonstrating the     reduction of emissions of sulphur dioxide     for one location over time. What     improvements for the environment and     human health do you think will have     happened as a result of the changes you     observe? 2. What are the key drivers and modifiers of    atmospheric movement in the troposphere? 6. Why were dilute and disperse policies not    a successful means of overcoming    problems associated with acidification? 3. Compare and contrast air pollution     problems in two locations around the     globe in contemporary times. How do     these differ to conditions 50 years ago? 7. With reference to the suggested texts and     references in this section, outline the     implications of climate change for your     continent, your country and your nearest     city. 4. Using the data from the internet, plot a    graph of carbon dioxide concentrations    over time. Click here to view the suggested     website for this work

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FURTHER READING
The text in this chapter has drawn heavily on a number of introductory texts describing different
aspects of the atmosphere. These are recommended as starting point for further study
and to provide greater depth to the ideas that have been introduced in this section. Although all are introductory texts, they differ in terms of overall focus and level of detail. They are listed in order of the author’s assessment of the general level, accessibility and detail of material they contain:

• Crutzen, P. J. and Ramanathan, V. (2000) ‘The ascent of the atmospheric sciences’. Science 290, 299–304.
  A paper that summarizes the key research findings that have developed humankind’s understanding of the atmosphere.
  
• Ahrens, C. D. (1998) Essentials of Meteorology: An Invitation to the Atmosphere. Belmont, USA: Wadsworth Publishing.
  A readable, richly illustrated introductory text covering the principles of the atmosphere and their relationship to meteorology.
  
• Lutgens, F. K. and Tarbuck, E. J. (1998) The Atmosphere: An Introduction to Meteorology. Upper Saddle River, New Jersey: Prentice Hall International Inc.
  Another nicely illustrated introductory text covering a wide range of issues and concepts associated with the atmosphere.