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28.
Simultaneous Collection of Ambient Aerosol to Measure PAHS, Trace
Elements, EC-OC, Ions AND PM2.5 Mass
Arantzazu
Eiguren-Fernandez, Suresh Thurairatnam and Antonio H. Miguel
Southern California Particle Center and Supersite, University
of California Los Angeles, 650 Charles E. Young Dr., Los Angeles,
CA, 90095
We used an integrated sampling system to simultaneously collect
aerosols to measure PM2.5 mass, EC and OC, ions, metals, and organics.
The system, model LS-TM-XAD (L. Sheetz Enterprises, Reno, NV)
has a PM2.5 cut cyclone inlet and runs at a total flow rate of
113 lpm. After passing through the cyclone, the air flow is divided
into three different branches or legs, each consisting of individual
flow adjustment valves and TSI mass flow meters. The first leg
collects aerosol particles on a 47 mm quartz filter for EC-OC
measurements; the second collects samples on a 47 mm Teflon filter
for PM2.5 mass, ions and trace elements; the third leg collects
particles on a 10 cm dia. Teflon coated fiber filter for particulate
organics (PAHs and Oxy-PAHs) and, downstream, 20 g of XAD-4 resin
for vapor-phase organics. This PUF-less system is a modification
of the “PUF-XAD-PUF” system, and improves sample analysis
by reducing blank levels from PUF interferents.
We evaluated the performance of this new sampling arrangement
on December 11-12, 2003, during a two-day intensive experiment
conducted at the South exit of the Sepulveda Tunnel, located under
a runway at LAX airport, in Los Angeles. Samples were collected
from 2:00 pm to 6:30 pm at approximately one hour intervals. We
used 20 lpm flow rates for the 47 mm legs and 73 lpm for the vapor-
and particle-phase leg.
We will discuss the results in light of the effects of traffic
density on the measured target species, and the advantage of this
PUF-less sampling system.
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