Aircraft and ground-based measurements of hydroperoxides during the 2006 MILAGRO field campaign

L. J. Nunnermacker (1) , J. B. Weinstein-Lloyd (2) , B. Hillery (2) , B. Giebel (3) , L. I. Kleinman (1) , S. R. Springston (1) , P. H. Daum (1) , J. Gaffney (4) , N. Marley (4) , G. Huey (5)

1 BNL - Brookhaven National Laboratory [Upton, NY]
2 Chemistry/Physics Department
3 RSMAS - Rosenstiel School of Marine and Atmospheric Science
4 Department of Chemistry
5 School of Earth and Atmospheric Sciences [Atlanta]

Mixing ratios of hydrogen peroxide and hydroxymethyl hydroperoxide were determined aboard the US Department of Energy G-1 Research Aircraft during the March 2006 MILAGRO field campaign in Mexico. Ground measurements of total hydroperoxide were made at the T1 site at Universidad Technologica de Tecámac, about 35 km NW of Mexico City. In the air and on the ground, peroxide mixing ratios near the source region were generally near 1 ppbv, much lower than had been predicted from photochemical models based on the 2003 Mexico City study. Strong southerly flow resulted in transport of pollutants from the T0 to T1 and T2 surface sites on several flight days. On these days, it was observed that peroxide concentrations slightly decreased as the G-1 flew progressively downwind. This observation is consistent with low or negative net peroxide production rates calculated for the source region and is due to the very high NO_x concentrations above the Mexico City plateau. However, relatively high values of peroxide were observed at takeoff and landing near Veracruz, a site with much higher humidity and lower NO_x concentrations.

Domaines: Océan, Atmosphère

L. J. Nunnermacker, J. B. Weinstein-Lloyd, B. Hillery, B. Giebel, L. I. Kleinman, et al.. Aircraft and ground-based measurements of hydroperoxides during the 2006 MILAGRO field campaign. Atmospheric Chemistry and Physics Discussions, 2008, 8 (3), pp.8951-8995. ⟨hal-00304164⟩