Homework Questions for Chapter 18 - Air Pollution

Consult Syllabus for Due Date

Questions 1 and 2 will be turned in for a grade. Questions 3-9 will be discussed by the discussion groups in class so please look them over before the discussion session.

Follow the Problem solving steps discussed in class

1. a.  Mathematically, how do you define the percentage change of any quantity?

b.  Let's assume that the density of ozone in the LA basin area on a given summer morning is 1 gram m-3 at 10 AM.  Also assume that the mixing height is 0.5 km.  Within the next hour, the mixing height increases to 1.5 km while the mass of ozone in the LA basin area is constant.  What is the percentage change in ozone density from 10 AM to 11 AM?

2.  Given a surface temperature of 30 degrees Celsius.  Write down equations for the vertical profile of environmental temperature that would support the following plume patterns:

• fanning
• coning
• looping

For each plume pattern, what is the environmental air temperature at 2 km?

3.

a. Suppose clouds of nitrogen dioxide drift slowly from a major industrial complex over a relatively unpopulated area. If the area is essentially "free" of hydrocarbons, would you expect high levels of tropospheric ozone to form? Explain.

b. Now suppose that the clouds of nitrogen dioxide drift slowly over an area that has a high concentration of hydrocarbons from both natural and industrial sources. Would you expect high levels of tropospheric ozone to form under these conditions? Explain your reasoning.

4. For least-polluted conditions, what would be the best time of day for a farmer to burn agricultural debris? Explain why you chose that time of the day.

5. Why are most severe air pollution episodes associated with subsidence inversions rather than radiation inversions?

6. What surface and upper-air conditions lead to atmospheric stagnation?

7. Urban areas tend to be more cloudy than the surrounding rural areas. Since clouds reflect incoming short wave radiation, why are urban areas generally warmer than the surrounding rural areas?

8. Why do we want to reduce high ozone concentrations at the Earth's surface while also wishing to increase ozone concentrations in the stratosphere?

9. Acid snow can be a major problem. In the high mountains of the western U.S., especially downwind of a major metropolitan or industrial area, explain why, for a high-mountain lake, acid snow can be a greater problem than acid rain, even when both have the same pH.

10. What atmospheric conditions would produce a lofting smoke plume pattern during the middle of the afternoon?