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UNIVERSIDAD DE GUANAJUATO

DEPARTAMENTO DE INGENIERA QUMICA

CIENCIA Y TECNOLOGA AMBIENTAL (SEPTIEMBRE 2014)

ATMOSPHERE EXERCISES

1. In general terms, what is meant by "photochemical smog"? What are

the initial reactants in the process? Why is sunlight required?

2. What is meant by a "primary" pollutant and by a "secondary" pollutant?

Give examples.

3. What is the chemical react ion by which most atmospheric NO initially

is produced? From which two sources do most urban NOarise?

4. Describe the strategies by which reduction of urban ozone levels have

been attempted. What difficulties have been encountered in these

efforts?

5. Describe the processes bv which the "three-way catalyst" works to

transform air pollutants released by an automobile engine.

6. Define the term aerosol, and differentiate between "coarse" and "fine"

particulates. What are the usual origins of these three types of

atmospheric particles.

7. What are the main sources of formaldehyde in indoor air? What are

its effects?

8. What are the main sources of nitrogen dioxide and of carbon monoxide in

indoor air?

9. What are the two forms of asbestos? Why is asbestos of environmental

concern?

10. What is the two-step mechanism by which the hydroxyl free radical is

produced in clean air?

11. Explain why OH reacts more quickly to abstract hydrogen from

other molecules than does HOO.

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12. What is the fate of OH radicals that react with NO? with

NO2? with other OH?

13. What is the fate of NO2 molecules that photodissociate? that react

with ozone? that react with RC(O)OO radicals?

14. Why does the production of high concentrations of NO lead to an

increase in ozone levels in air? Why does this not occur if much NOis

present?

15. Describe both the homogeneous and the heterogeneous mechanisms

by which sulfur dioxide is oxidized in the atmosphere. What are the

oxidizing agents? Are any of the processes affected by pH?

16. What is the nature of the radioactive emissions and particles?

Why are the former more dangerous to health?

17. Explain the origin of radon in buildings.

18. Explain why the "daughters" of radon are more dangerous to health

than is radon itself.

19. Explain the chain reaction for stratospheric ozone depletion.

20. Deduce the formulas for the CFCs 12, 113, 123, 134.