8.1
Ambient measurements of N2O5 during SHARP using cavity ringdown spectroscopy
Justine N. Geidosch, Texas A&M University, College Station, TX; and K. C. Perkins and S. W. North
The formation of N2O5 provides the major pathway for NOx removal at night, and the quantization of urban ambient concentrations will help to complete the total nitrogen budget. Nocturnal ambient measurements of N2O5 were performed during the SHARP field campaign from 15 April through 31 May 2009 in Houston, TX. Utilizing cavity ringdown spectroscopy (CRDS), N2O5 was detected through thermal decomposition to NO2 and NO3 followed by absorption of 662 nm radiation by the nitrate radical. Texas A&M's dual cell CRDS instrument was located on top of Moody Tower, an 18-story building approximately 5 km southeast of downtown Houston. Attempts were made to quantify NO3 concentrations, however none was observed. Preliminary results show N2O5 was observed in varying concentrations ranging to a maximum of 300 ppt. Discussion of the results in the contexts of the SHARP scientific mission will be presented.
Session 8, The Study of Houston Atmospheric Radical Precursors (SHARP) - III
Thursday, 21 January 2010, 1:30 PM-3:00 PM, B315
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