SO2 Artifact testing

15:18 Begin std add with SM UHP air above canopy
15:30 End std add, remain above canopy; peak ~0.5 ppb, So2 artifact ~0.1-0.15 ppb
15:36 Resume sample switching, begin above canopy

16:18 Begin std add with SM UHP air above canopy; peak ~0.1 ppb
16:30 End Std add, remain above canopy; artifact difficult to discern
16:36 Resume Sample switching, begin above canopy

17:18 Begin std add with SM UHP air above canopy
17:30 End Std add, remain above canopy; peak and potential artifact similar to previous hour
17:36 Resume Sample switching, begin above canopy

17:18 Begin std add with SM UHP air above canopy
17:30 End Std add, remain above canopy; peak and potential artifact similar to previous hour, hard to distinguish from ambient
17:36 Resume Sample switching, begin above canopy

Plan to go to tower after dinner and switch to stainless line and set up for regular overnight cal.

JF