TY - JOUR A1 - Nehr, Sascha A1 - Franzen-Reuter, Isabelle A1 - Kucejko, Catharina T1 - New directions: Future approaches to the standardized assessment of airborne pollutants affecting environmental quality JF - Atmospheric Environment KW - Luftreinhaltung Y1 - 2017 U6 - https://doi.org/10.1016/j.atmosenv.2017.06.051 SN - 1352-2310 VL - 166 SP - 570 EP - 572 PB - Elsevier ER - TY - GEN A1 - Nehr, Sascha A1 - Borowiak, Annette A1 - Herrmann, Hartmut A1 - Wiesen, P. A1 - Zellner, Reinhard T1 - New and emerging technologies: Impact on air quality and climate - 3rd VDI/DECHEMA/GDCh Expert Forum on Atmospheric Chemistry (EFAC 3) T2 - Gefahrstoffe Reinhaltung der Luft KW - Luftreinhaltung Y1 - 2017 VL - 77 IS - 1/2 SP - 15 EP - 18 PB - Springer-VDI-Verl. ER - TY - JOUR A1 - Kaminski, Martin A1 - Fuchs, Hendrik A1 - Acir, Ismail-Hakki A1 - Bohn, Birger A1 - Brauers, Theo A1 - Dorn, Hans-Peter A1 - Häseler, Rolf A1 - Hofzumahaus, Andreas A1 - Li, Xin A1 - Lutz, Anna A1 - Nehr, Sascha A1 - Rohrer, Franz A1 - Tillmann, Ralf A1 - Vereecken, Luc A1 - Wegener, Robert A1 - Wahner, Andreas T1 - Investigation of the β-pinene photooxidation by OH in the atmosphere simulation chamber SAPHIR JF - Atmospheric Chemistry and Physics N2 - Abstract. Besides isoprene, monoterpenes are the non-methane volatile organic compounds (VOCs) with the highest global emission rates. Due to their high reactivity towards OH, monoterpenes can dominate the radical chemistry of the atmosphere in forested areas. In the present study the photochemical degradation mechanism of β-pinene was investigated in the Jülich atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber). One focus of this study is on the OH budget in the degradation process. Therefore, the SAPHIR chamber was equipped with instrumentation to measure radicals (OH, HO2, RO2), the total OH reactivity, important OH precursors (O3, HONO, HCHO), the parent VOC β-pinene, its main oxidation products, acetone and nopinone and photolysis frequencies. All experiments were carried out under low-NO conditions ( ≤  300 ppt) and at atmospheric β-pinene concentrations ( ≤  5 ppb) with and without addition of ozone. For the investigation of the OH budget, the OH production and destruction rates were calculated from measured quantities. Within the limits of accuracy of the instruments, the OH budget was balanced in all β-pinene oxidation experiments. However, even though the OH budget was closed, simulation results from the Master Chemical Mechanism (MCM) 3.2 showed that the OH production and destruction rates were underestimated by the model. The measured OH and HO2 concentrations were underestimated by up to a factor of 2, whereas the total OH reactivity was slightly overestimated because the model predicted a nopinone mixing ratio which was 3 times higher than measured. A new, theory-derived, first-generation product distribution by Vereecken and Peeters (2012) was able to reproduce the measured nopinone time series and the total OH reactivity. Nevertheless, the measured OH and HO2 concentrations remained underestimated by the numerical simulations. These observations together with the fact that the measured OH budget was closed suggest the existence of unaccounted sources of HO2. Although the mechanism of additional HO2 formation could not be resolved, our model studies suggest that an activated alkoxy radical intermediate proposed in the model of Vereecken and Peeters (2012) generates HO2 in a new pathway, whose importance has been underestimated so far. The proposed reaction path involves unimolecular rearrangement and decomposition reactions and photolysis of dicarbonyl products, yielding additional HO2 and CO. Further experiments and quantum chemical calculations have to be made to completely unravel the pathway of HO2 formation. KW - Luftreinhaltung Y1 - 2017 U6 - https://doi.org/10.5194/acp-17-6631-2017 SN - 1680-7324 VL - 17 IS - 11 SP - 6631 EP - 6650 PB - Copernicus ER - TY - GEN A1 - Walser, Sandra M. A1 - Theloke, Jochen A1 - Nehr, Sascha A1 - Brenner, Bernhard A1 - Herr, Caroline E. W. T1 - Gemeinschaftsausschuss „Bioaerosole und biologische Agenzien“ der VDI/DIN-Kommission Reinhaltung der Luft T2 - Umweltmedizin - Hygiene - Arbeitsmedizin KW - Luftreinhaltung Y1 - 2017 VL - 22 IS - 2 PB - ecomed-Storck ER - TY - JOUR A1 - Herr, Caroline E. W. A1 - Brenner, Bernhard A1 - Thekoke, Jochen A1 - Nehr, Sascha A1 - Winkler, Gisela T1 - Erfahrung mit dem LAI Leitfaden bei der Bewertung von Bioaerosoleemissionen aus Anlagen JF - Das Gesundheitswesen KW - Luftreinhaltung Y1 - 2017 U6 - https://doi.org/10.1055/s-0037-1602110 SN - 0941-3790 VL - 79 IS - 4 SP - 299 EP - 374 PB - Thieme ER - TY - JOUR A1 - Nehr, Sascha A1 - Hösen, Elisabeth A1 - Tanabe, Shin-ichi T1 - Emerging developments in the standardized chemical characterization of indoor air quality JF - Environment International KW - Indoor air quality KW - Indoor air chemistry KW - Online-measurement KW - Non-target-screening KW - Indoor air quality management KW - Luftreinhaltung Y1 - 2017 U6 - https://doi.org/10.1016/j.envint.2016.09.020 SN - 0160-4120 VL - 98 SP - 233 EP - 237 PB - Elsevier ER -