Testing the daytime oxidizing capacity of the troposphere: 1994 OH field campaign at the Izaña Observatory, Tenerife

A field campaign was carried out during May 1994 at the Izaña station, Tenerife. This campaign was part of the program Environment and Climate sponsored by the European Commission to study the influence of European emissions on the oxidizing capacity of a clean tropospheric environment. Daytime and also nighttime measurements were made, covering the OH as well as the NO3 chemistry. This paper presents the OH measurements taken with a multipass optical absorption spectrometer (MOAS) and discusses the daytime chemistry in a statistical and therefore more preliminary way. All relevant parameters influencing the OH concentration were monitored. From the data the two main contributions to the OH production can clearly be discerned and are given by the primary production following the ozone photolysis and the O(1D)-H2O reaction and by the catalytic reactions of NOx in the recycling process. The latter processes prove to contribute a dominant part to the OH concentration. The measurements of the nonmethane hydrocarbons (NMHC) especially of the biogenics, indicate a considerable influence of the NMHC on the absolute values of the OH concentration at Tenerife.This work has been financially supported by the European Commission (grant EV5V-CT93-0321), by the DFG, and by the Fonds der Chemischen Industrie, which is gratefully acknowledged

Cross-Lineage Influenza B and Heterologous Influenza A Antibody Responses in Vaccinated Mice: Immunologic Interactions and B/Yamagata Dominance

The annually reformulated trivalent inactivated influenza vaccine (TIV) includes both influenza A/subtypes (H3N2 and H1N1) but only one of two influenza B/lineages (Yamagata or Victoria). In a recent series of clinical trials to evaluate prime-boost response across influenza B/lineages, influenza-naïve infants and toddlers originally primed with two doses of 2008–09 B/Yamagata-containing TIV were assessed after two doses of B/Victoria-containing TIV administered in the subsequent 2009–10 and 2010–11 seasons. In these children, the Victoria-containing vaccines strongly recalled antibody to the initiating B/Yamagata antigen but induced only low B/Victoria antibody responses. To further evaluate this unexpected pattern of cross-lineage vaccine responses, we conducted additional immunogenicity assessment in mice. In the current study, mice were primed with two doses of 2008–09 Yamagata-containing TIV and subsequently boosted with two doses of 2010–11 Victoria-containing TIV (Group-Yam/Vic). With the same vaccines, we also assessed the reverse order of two-dose Victoria followed by two-dose Yamagata immunization (Group-Vic/Yam). The Group-Yam/Vic mice showed strong homologous responses to Yamagata antigen. However, as previously reported in children, subsequent doses of Victoria antigen substantially boosted Yamagata but induced only low antibody response to the immunizing Victoria component. The reverse order of Group-Vic/Yam mice also showed low homologous responses to Victoria but subsequent heterologous immunization with even a single dose of Yamagata antigen induced substantial boost response to both lineages. For influenza A/H3N2, homologous responses were comparably robust for the differing TIV variants and even a single follow-up dose of the heterologous strain, regardless of vaccine sequence, substantially boosted antibody to both strains. For H1N1, two doses of 2008–09 seasonal antigen significantly blunted response to two doses of the 2010–11 pandemic H1N1 antigen. Immunologic interactions between influenza viruses considered antigenically distant and in particular the cross-lineage influenza B and dominant Yamagata boost responses we have observed in both human and animal studies warrant further evaluation

In-situ Measurements of Tropospheric Hydroxyl Radicals by Folded Long-Path Laser Absorption During the Field Campaign POPCORN

Absolutely calibrated in-situ measurements of tropospheric hydroxyl radicals, formaldehyde, sulfur dioxide, and naphthalene (C10H8) were performed by long-path laser absorption spectroscopy during the field campaign POPCORN. The absorption light path was folded into an open optical multiple reflection cell with a mirror separation of 38.5 m. Using a light path length of 1848 m and an integration time of 200 s, the average 1 sigma-detection limits of OH, HCHO, SO2 and C10H8 during POPCORN were 8.710(5) cm(-3): 8.3.10(9) cm(-3), 2.4.10(9) cm(-3), 1.5.10(8) cm(-3), respectively. In total, 392 identifications of OH in air spectra were made in a rural environment between August 5 and August 23, 1994. We present and discuss OH absorption spectra and diurnal OH concentration profiles of three days which are representative for measurements under different pollution conditions during POPCORN. The observed maximum and median OH radical concentrations are 1.3.10(7) OH/cm(3) and 4.0.10(6) OH/cm(3), respectively. The measured diurnal variation of the OH concentration shows a good correlation with the primary formation reaction of OH radicals which is the photolysis of ambient ozone. Deviations from this correlation in the morning and evening hours, when the OH concentration is higher than expected from the ozone photolysis, demonstrate the importance of other photochemical HOx production pathways during POPCORN

Troposphaerische OH Messungen mit Hilfe eines schnell durchstimmbaren Laserspektrometers in Langwegabsorption und Vergleich mit Modellrechnungen Abschlussbericht

The Frankfurt MOAS instrument is a multicomponent laser spectrometer especially designed for the monitoring of tropospheric trace gases, in particular OH. The sensitivity is better than one part in 10"5 (SN = 1) under tropospheric conditions for a 1 min averaging time and a 1.2 km absorption path length folded inside a 6 m multiple reflection system. This sensitivity corresponds to an OH concentration of 2-3x10"5 OH/cm"3. The instrument can be operated simultaneously on the fundamental and the second harmonic performing insitu measurements of tropospheric OH, SO_2, CH_2O and naphtalene in the uv, and NO_2 in the vis. All measurements are made simultaneously with high spatial and temporal resolution inside the same well defined volume. Three field campaigns have been carried out during this BMFT project, two in Germany - in 1991 at the Black Forest and in 1992 at the Taunus Mountains - and the third one in 1993 at Tenerife. The measurements performed at these different sites clearly demonstrate the mobility of the MOAS instrument. The obtained air spectra show unequivocally that the MOAS data provide a proper basis for meaningful tests of model calculations. Correlated short time variations of the OH and of its controlling parameters on a time scale of minutes or less were observed during most registered episodes demonstrating that the air masses were not homogeneously mixed. This is an important result as the chemistry involved is non linear and averaging in time and space will thus introduce errors into the interpretation of the data. The most valuable outcome of the presented project is that the experimentally determined trends of the OH concentrations qualitatively mostly follow the theoretical predictions. The quantitative analysis, however, rises still a number of questions, especially concerned with the completeness of the chemistry taken into account. In particular should be underlined in this context that two special events - a forest fire and a summer smog episode (both observed after the reported project) - are in need of an extended interpretation, and it is very likely that NMHCs play here an important role. (orig.)Available from TIB Hannover: F95B1311+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman