Characteristics of the NO-NO2-O3 system in different chemical regimes during the MIRAGE-Mex field campaign
1Department of Environmental Engineering, Dong-Eui University, 995 Eomgwangno, Busan 614-714, Republic of Korea
2Atmospheric Chemistry Division, National Center for Atmospheric Research, P.O. Box 3000 Boulder, CO 80307, USA
3School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30318, USA
Abstract. The NO-NO2 system was analyzed in different chemical regimes/air masses based on observations of reactive nitrogen species and peroxy radicals made during the intensive field campaign MIRAGE-Mex (4 to 29 March 2006). In general, NO2/NO ratios, which can be used as an indicator to test current understanding of tropospheric chemistry mechanism, are near photostationary state. The air masses were categorized into 5 groups: boundary layer (labeled as "BL"), free troposphere (continental, "FTCO" and marine, "FTMA"), biomass burning ("BB"), and Tula industrial complex ("TIC"). The time- and air mass-dependent NO2/NO ratios ranged from 2.35 (TIC) to 5.18 (BB), while the NOx/NOy ratios varied from 0.17 (FTCO) to 0.54 (BL). The ozone production efficiency for the 5 air mass categories ranged from 5.0 (TIC) to 10.2 (BL), indicating photochemically young and reactive air masses.