Semivolatile Particulate Matter Study (March 2005,
Lindon, UT)
One major issue in the sampling of aerosol particles is what technique
is best? One problem for many analytical methods is that many components
of fine particulate matter are "semi-volatile", that is they can change forms
between the particle phase (solid/liquid) and the gas phase. (vapor) This
is a significant issue in sampling particles and getting the "right" answer
because some methods can miss particle components (a negative artifact).
This could happen for instance, if a compound were collected and then
the compound converted into its gaseous form before analysis. To answer
this, we initiated a study to observe how the particulate concentrations
and composition in school environments varied with the outdoor levels. During
March, 2005, we moved our
aerosol mass spectrometer
to Lindon, Utah in a collaborative project with
Professor Delbert Eatough
of BYU. Dr. Eatough has long had an interest in characterizing the
semivolatile components of airborne particles. In order to characterize
these components, you need analytical methods with a fast time response.
Professor Eatough arranged to get several techniques at his sampling
site, and we provided the AMS which also can sample with rapid time response.
Lindon Site:
The Lindon sampling site is located at the back of an elementary school in
Lindon, UT. On the left, you can see the sampling shed that belongs
to the Utah Division of Air Quality. Like all of their sampling site,
they provide real-time data to the web from the Lindon site. You can
access the DAQs current data for
Lindon here
. The sampling shed on the right is Dr. Eatough's shed which housed
the AMS and many other state-of the art instrumentation for rapid analysis
of aerosols. The inside of the trailer was quite cramped as you can
see below! But this is good because it meant we have lots of data to
compare too. Inside the trailer, we have an real-time
EC/OC analyzer for quantifying organic and elemental carbon in particles.
We also have a TEOM and an FDMS TEOM (figures out volatile portion
of the particle mass loadings.) In addition, a semi-continuous ion
chromatograph developed by
Professor Sandy Dasgupta
at Texas Tech University is used for determination of ammonium, sulfate,
nitrate,and chloride in the gas and particle phase.
Data analysis of the Lindon data set is ongoing. Because of delays
in getting some of the instrumentation and because our study in Logan went
late, we did not get to Lindon until March. As this time was past the
inversion season, we did not see very high concentrations of fine particles.
However, we still have many instruments to compare our acquired data
too, so we are busy analyzing this data set. Below is simply an overall
mass concentration plot from our study in Lindon. Most of the particle
mass detected was in the organic carbon fraction, with nitrate the second
biggest component.
We want to thank the Eatough research group for inviting us on this study
and especially Delbert and Norman Eatough and the USU moving crew for helping
us get into and out of the trailer which was a tight fit!
This page was last updated: June 30, 2005
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