Working with Andreas

Joined: 23 Mar 2004 Posts: 72

Today has been a very science-filled day. I spent the day with Andreas, from the University of California-Irvine. His part of the study is very similar to that of Jack and Kelly. He is taking samples, and analyzing those samples. The difference is that Jack and Kelly were looking for acids in the snow and air, while Andreas is measuring chemicals called hydrocarbons (made up of atoms of hydrogen and carbon) and halocarbons (composed of halogens and carbon). These chemicals are also mostly pollutants. They are also created by cars and power plants.

Hydrocarbons (gases like methane and propane) can be broken apart by a chemical called a hydroxyl radical (OH), which is produced in the snow. This is a good thing, because it helps to get rid of some of the pollutants in the air. What this study seems to be revealing is that when the OH breaks these gases apart, it gets rid of some, but creates others. As a result, there is a constant breaking apart of large hydrocarbons and formation of hydrocarbons in the snow.

In order to determine the amounts of hydrocarbons present in the snow, Andreas has a series of cans in the Bally lab.

Some of these cans are connected by stainless steel tubing (hydrocarbons don’t stick to stainless steel) that comes from the group sampling probe. From there, they are able to collect air samples from within the snow and trap the air in the pressurized cans. These cans are then sent to the UC-Irvine lab where they are analyzed for the amount of hydrocarbons in each can. Another stainless steel tube is suspended above the bridge to collect air from above the snow. We do the exact same process to collect the samples and to analyze them.

Since hydroxides (OH) are known to break these hydrocarbons apart, we need to know how much OH is forming in the snow. There really isn’t an easy way to do this, because hydroxyls change very, very quickly. The test that we did was really an estimation of how much hydroxyl is in the snow.

Andreas took a syringe filled with a gas (SF6) that does not react quickly with OH and pushed it into a probe. There is a clear box with a pump attached at one end to draw the “loaded” air toward one end of the box. As the air moves toward the end of the box, it is drawn up into two probes and samples are pulled from there. Those samples are collected, and put through a machine (gas chromotograph or GC). This GC tells us how long it takes air to move through that chamber. Knowing this will help him estimate how much OH (Hydroxyl radical) is in the snow.

That estimation is made by putting known amounts of hydrocarbons into the chamber, and looking at how many are left when the air is pulled out.

I spent a chunk of the afternoon entering the air samples from this second experiment into this GC. It was kind of fun! I felt like a “real scientist” Smile

FOOD UPDATE: I ATE MUSK OX!!!!! As much as I hate to admit it, it was delicious. Tasted just like a beef roast. The musk ox we had at camp looked sooo much better than the stuff on the pizza!

Nikki