9.6
Measurements of PANs at the La Porte Supersite during the TexAQS 2000 Houston Intensive Study.
James M. Roberts, NOAA Aeronomy Laboratory, Boulder, CO; and E. J. Williams, B. T. Jobson, P. C. Murphy, W. Kuster, P. D. Goldan, D. D. Riemer, E. C. Apel, and F. C. Fehsenfeld
Peroxcarboxylic Nitric Anhydrides (PANs) are important by-products of hydrocarbon (HC)-NOx photochemistry. The most abundant compound, peroxyacetic nitric anhydride (PAN) is correlated with O3 in urban and regionally polluted atmospheres. Relative concentrations of the minor PANs; peroxypropionic nitric anhydride (PPN), peroxymethacrylic nitric anhydride (MPAN), peroxyisobutyric nitric anhydride (PiBN) can be used to indicate the origin of HCs that participated in O3 formation. The measurements at the La Porte supersite were conducted between August 15 and September 13, 2000. The PANs measured during that time revealed several things; high ozone events were associated with anthropogenic hydrocarbons, and only minor biogenic hydrocarbon chemistry was observed and was not associated with high O3. A new PAN compound, peroxyacrylic nitric anhydride (APAN), was observed in abundances up to 30% of PAN. This compound is thought to result from local chemistry involving petrochemical sources of 1,3-butadiene and acrolein.
Session 9, TEXAQS air Quality Study: Part I
Wednesday, 16 January 2002, 1:30 PM-4:00 PM
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