Ryan Hamilton and Dr. Lawrence Rees, Physics and Astronomy; Dr. Nolan Mangelson, Chemistry; Dr. Delbert Eatough, Chemistry

In an effort at reducing the carbon monoxide levels in the atmosphere, Utah has mandated the use of oxygenated fuels during winter inversions. While the fuel additive has been shown to reduce CO levels by as much as 4%, the unique chemistry of the air in Utah Valley has raised concerns about the oxygenated fuels contributing to air pollution in the form of fine particulate matter–a pollutant recently brought under tighter regulation by the EPA. To diagnose the problem, air samples from around Utah Valley were taken during the winter, both in times of inversion and in times when there was no inversion.

To measure the pollutants in the atmosphere, a known quantity of air is pulled through micropore filter. These filters are designed to stop and trap all of the particles in the air large enough to be of concern. The filters are then stored individually and frozen to keep the more volatile compounds from being lost.

This is where the project stood when I took over. The first step was to prepare the filters for analysis. They were to be analyzed using PIXE methods, by bombarding them with energetic protons courtesy of Brigham Young University’s 2 MeV Van de Graaff proton accelerator. In order for them to be run, the filters had to be thawed, weighed, trimmed, and attached to small aluminum slides.

PIXE stands for Proton Induced X-ray Emission. It is a technique used to determine the trace element content of a sample. First, protons are accelerated and fired into a target. As these positively charged protons come close to the individual atoms in the target, they are often able to strip negatively charged electrons away. Electrons move around the nucleus of an atom in shells of a specific energy level. As the shells get farther away from the nucleus, more energy becomes associated with the electrons in those shells. Whenever a proton comes close enough to the atom to rip away an inner-shell electron, an electron from an outer shell will shed some of its energy and fall into the lower shell. This energy is shed in the form of x-rays. The properties of these x-rays, called characteristic x-rays, are known and unique for each element. Thus they become a “fingerprint” for each element. By collecting and analyzing these x-rays, we are able to determine the elements and their quantities in a given sample.

The elements of particular interest in this study were iron, calcium, silicone, sulphur, and potassium. These were measured and then analyzed by a program called Gupix. Gupix is able to take the information collected on x-rays and compute the amounts of elements in the samples, correcting for uncertainties and even compute the percent error associated with each element. This information is then input into a spread sheet for ease of handling.

At the time of writing this paper, this is where the project stands. Due to equipment failure and scheduling conflicts, the final analysis of this information has not yet been done. I project that it will be completed in the next few weeks.

The final step is to take this data and enter it into a series of lineal equations to obtain our final results. Air pollution can come from many sources, but each has its own unique signature. The equations are designed to determine how much of each element may be attributed to each of the major sources. The major pollution contributors in Utah Valley are the Geneva steel refinery, wood smoke, and auto emissions. Because auto emissions are our primary area of concern, we will use known information to remove the information about Geneva and wood smoke to give us just the information we want. In short, this will be accomplished by normalizing the potassium by the silicone and calcium levels to remove wood smoke, and normalizing the silicone by the iron to account for Geneva. When the chemical processes of burning wood and refining steel occur, proportionate levels of the elements listed above are released into the atmosphere. Thus, even though silicone, for example, may be released by multiple pollutant sources, comparing the silicone levels with the iron levels will give us an accurate measure of the amount of silicone coming from Geneva.

The resulting pollutant levels from automobile exhaust will allow us to draw conclusions about the possible harm that oxygenated fuels are doing to the air quality of Utah Valley. I expect that these results will be published.