NH4/NO3/SO4 Zero Filter Check

Purpose: The NH4/NO3/SO4 system measures particulate SO4 and NH4NO3 by reducing these aerosols down to their gaseous precursor species, SO2 and NO, respectively. After a series of denuder differences, these gasses are measured in the TEI trace gas analyzers. To test that the systems are operating correctly, a zero filter check can be done to eliminate all the particulate from the sample air.

Required Equipment: BIOS tubing; large blue Balston filter; adapter (identical to the Aeth/Neph adapter)

Reference: SOPMAN

1. Down the NH4NO3 and SO4 channels

2. Remove the sharpcut cyclone from the NH4/NO3/SO4 inlet.

3. Connect the Balston filter to the inlet using the adapter and BIOS tubing.

4. Let the instruments sample for 15 minutes.

5. Open Data query (1 minute average).

6. Record the last 3 minute averages into the site log and any form attached to the Track Ops ticket.

7. Remove filter assembly from inlet and replace Cyclone.

8. Up the NH4NO3 and SO4 channels.