Observations of APAN during TexAQS 2000

Measurements of peroxycarboxylic nitric anhydrides (PANs) made in Houston, Texas during TexAQS (Texas Air Quality Study) 2000 showed a relatively abun dant PAN compound that had not been identified in previous studies in North America [cf. Williams et al., 2000]. This compound was hypothesized to be peroxyacrylic nitric anhydride {CH2=CHC(O)OONO2, APAN} based on the work of Tanimoto and Akimoto, [2001]. APAN was synthesized and characterized on on e of the two GC systems used to make those measurements, subsequent to the TexAQS 2000 field study, confirming that APAN was observed during TexAQS 20 00, both on the ground and in airborne measurements. Mixing ratios of APAN were estimated from the response of the system to PAN and PPN and ranged up to 502 pptv, which was 30% of PAN. High APAN values were associated with t he precursor species 1,3-butadiene and acrolein, which had local petrochemi cal sources. The presence of APAN at these unprecedented levels demonstrate s the impact of these reactive VOC species, and may have associated health effects.