1. Are we polluting the Ridge’s precipitation? A study by Garrett Porter located on Niwot Ridge, Colorado. Performed on February 6, 2010 and presented on February 27, 2010 Winter Ecology – Spring 2010 Mountain Research Station – University of Colorado, Boulder

2. Topics Background Location Electrical Conductivity and pH Snowflake chemistry Dry and Wet Deposition Pollution Experiment Question Experimentation Results Conclusions Next Time Humans Remember

3. Location Due East of Continental Divide Niwot Ridge, CO Precipitation: Pacific Front 4 Corners Low Westerlies Arctic Blast

4. What is pH and EC? pH: Hydrogen Ion concentration Hydrogen Ion activity EC Dissolved material Salts

5. The Life of a Snowflake EC Rises

6. Dry and Wet Deposition Wet deposition: Snow falling Attach Trapped Rain Gravity Dry deposition: Gravity Heavier particles

7. What Pollution? Nitrate & Nitrite levels on the rise Increases pH Ecology Flora Fauna Aerosols

8. So... Is there actually a problem with pH and EC in snow, our future water? If so, does the depth of the snow during winter play any sort of role in creating a gradient?

9. February 6, 2010 2:00PM MST 42 ° F Low, steady wind Clear Area: Trees Drifts Eastern side of sharp embankment (Saddle)

10. Two snow pits Pit 1: Upslope 6 samples at 20cm intervals Pit 2: Downslope 5 samples at 20cm intervals

11. Results Sample Snow pit EC 1 118.0 2 123.5 3 114.0 4 111.7 5 113.9 6 121.0 7 212.9 8 26.5 9 2 10 243.0 11 224.0

13. Downwind versus Upwind High-low-high trend Largely inconclusive More sampling Better location Conclusions

14. For Next Time Better Area Sheltered Well preserved Better instrumentation More precise On site measurements More Samples Melting patterns Chemical composition Fresh snow Multiple snowfalls Plot versus time

15. So, is it polluted? Not exactly apparent yet Long term records say otherwise Nitrates higher Aerosols Sulfates

16. humans! Largest polluters Industrialization Safety Recreation

17. Remember? pH- Hydrogen concentration, activity EC- Electrical conductivity- dissolved matter Experimentation- Depth of snow versus EC Humans and our pollution

18. References www.epa.gov/acidrain/ http://www.its.caltech.edu/~atomic/snowcrystals/