The First Day: Oh Boy!

Well, after touring the town of Oak Ridge over the weekend, it was finally time to get down to business and start my internship. I've been pretty light on the topic of what I will actually be working on this summer, but that was mostly because even I didn't know the full extent of it. So here it goes. Some of this may get a bit technical, but just stick with it, I actually think I explained it pretty well!

The ATDD (picture available tomorrow) has installed two separate TEOM particulate monitors within the Oak Ridge/Knoxville region. The TEOM is actually a pretty neat instrument when you figure out how it works. An inlet valve at the top of the instrument takes in air at a rate of 16.7 L/min (via a vacuum pump) and is then diverted into a 3 L/min flow and a 13.7 L/min exhaust flow. Before diverting, however, the instrument is able to filter out particles of certain sizes (in this case greater than 2.5 microns). The inlet valve contains a certain curved geometry that allows for the passage of smaller particles but blocks those larger ones that we are not interested in. By changing this geometry, we are able to change which sizes we filter out.

After the initial filtering process, the 3 L/min flow progresses to what is called the mass transducer. This is simply a small filter that is resting on an oscillating hollow tube. The 2.5 micron particles then collect on this filter. The instrument is able to measure the accumulated mass because of the basic concepts of a mass spring system. By adding mass to the oscillating filter, the frequency of the oscillation must change. Since we know the change in frequency that has occurred, we can compute the mass of particulate matter on that filter. In order to compute a concentration (which we are really interested in), the instrument simply divides the mass by the flow rate (3 L/min) and a constant time ratio to arrive at a number with units of (microgram/m^3). This calculation is done every two seconds and the baseline mass is adjusted each time (so that the mass doesn't just keep adding up as particulates accumulate). This allows for instantaneous data which tells us the concentration of 2.5 micron particles. The instrument, however, computes a whole bunch of different timed averages (15 min, 30 min, 1 hour, 24 hour) in order to make the data more useful for analyzation.

After that long winded and involved description, lets get down to the important stuff. Why are we doing this?

Our first TEOM was installed next to the busy interchange of I-40 and Watt Road. Approximately 10,000 trucks per day pass this site, and trucks are constantly idling at the nearby truck stop. 2.5 micron particles are primarily produced by burning fossil fuels and other anthropogenic (aka human induced) sources. These particles and their health hazards will be discussed in an upcoming post. Therefore, it is believed that the concentration of these particles should be drastically higher along these populated industrial regions than in other areas.

For comparison purposes, a second TEOM was placed in the Walker Branch Watershed in Oak Ridge, TN. Let's just say that this instrument is basically in the middle of a bunch of nothing (aka, mountain ridge surrounded by trees). It is my job to analyze these two machines (in addition to other instruments in the region) and see if our hypothesis holds true.

In addition, daily weather conditions will be noted so that we can gain an increased understanding of how these particles behave in different atmospheric situations. Unstable conditions (think thunderstorm), for example, should allow for the transport and dispersion of these particles and not cause an extreme buildup within the local region. Strong and persistant high pressure, however, which is often common in the summer, should significantly hinder the transport of these particles and could create hazardous air quality levels. I guess we shall see!

My other project this summer involves traveling to Gulfport, MS with the research team for a 2-3 week period. This is a completely unrelated project that has nothing to do with air quality. I really don't know the complete details just yet, but it involves sea breeze circulations. I am actually really excited about this portion of the internship because it entails true field research, which I am extremely interested in.

So, to sum it all up, it looks like I will have 6-7 weeks of data analyzation mixed in with some field work in Oak Ridge, and 2-3 weeks of pure field research along the shores of Gulfport, MS.

In conclusion, this is my heart-felt thank you to all those big rigs and truck drivers who gave me the opportunity to study the byproducts of their amazing contributions to our planet.