1. Environmental Chemistry

2. Homework/Quizzes. 25% Class Participation
Homework/Quizzes           25% Class Participation             15% Midterm Exam  (Week of 3/19)    15%
Research Paper 20% Final                                       25%
Homework = 15%
Quizzes = 10%
8 total quizzes, 3 are dropped = 5 counted
Each quiz is 2 pts toward overall grade
I will weight individual part 25% and team part 75%
As of now, the class average quiz score is 84% (1 of 4 dropped)

3. Climate in the news…
warming.html?hp&action=click&pgtype=Homepage&clickSource=story- heading&module=second-column-region&region=top- news&WT.nav=top-news

5. Stratospheric Chemistry
The Ozone Layer - Shield against dangerous incoming radiation
How does radiation interact with molecules in the stratosphere?
What processes form and maintain the ozone layer?
How much ozone is there, and how is it distributed? How do we know?
How have human activities altered ozone chemistry and the ozone layer itself?
What controls have been put in place to protect the ozone layer?
Ozone is a “success story” in environmental chemistry – what lessons can we learn from it?
The stratosphere is also a good “case study” in how atmospheric chemistry works

6. Ozone layer characteristics

7. Global ozone
Ozone column – total amount of ozone between ground and top of atmosphere
Dobson Unit – an amount of ozone equivalent to a mm thick layer of ozone when brought to ground level
300 DU = 3 mm ozone colum

8. How is ozone measured?

9. Ozone Update NASA OzoneWatch: http://ozonewatch.gsfc.nasa.gov/
NOAA ESRL Global Monitoring Division Webpage:

10. Air circulation in the stratosphere
Air enters the stratosphere through the tropopause in the tropics
T is very low (200 K), so air in strat is DRY (~ 5 ppmv H2O)
T increases with alt so air is stratified – no vertical motion
Air stays in stratosphere for ~5 yrs before returning to troposphere

11. Solar spectrum

13. O2 Absorption Spectrum Graedel and Crutzen, Atmospheric Change, 1993
Schumann-Runge continuum
ionization continuum
Herzberg continuum
Schumann-Runge bands
Graedel and Crutzen, Atmospheric Change, 1993

14. Ozone UV absorption spectrum
Graedel and Crutzen, Atmospheric Change, 1993

15. Actinic Flux O2 O3

16. Comparing to observations
Ozone concentrations are lower than predicted based on oxygen-only chemistry

18. Global ozone
Ozone column – total amount of ozone between ground and top of atmosphere
Dobson Unit – an amount of ozone equivalent to a mm thick layer of ozone when brought to ground level
300 DU = 3 mm ozone colum

19. https://www. researchgate