TY - JOUR A1 - Alvarez, Elena Gómez A1 - Carslaw, Nicola A1 - Dusanter, Sébastien A1 - Edwards, Pete A1 - Gábor Mihucz, Viktor A1 - Heard, Dwayne A1 - Kleffmann, Jörg A1 - Nehr, Sascha A1 - Schoemacker, Coralie A1 - Venables, Dean T1 - Techniques for measuring indoor radicals and radical precursors JF - Applied Spectroscopy Reviews N2 - Radicals and their precursors play a central role in the chemical transformations occurring in indoor air and on indoor surfaces. Such species include OH, HO2, peroxy radicals, nitrous acid, reactive chlorine species, NO3, N2O5, Criegee intermediates, and glyoxal and methylglyoxal. Recent advances on instrumental analysis and modeling studies have demonstrated the need for a wider range of measurements of radical species and their precursors in indoor air. This work reviews measurement techniques and provides considerations for indoor measurements of several radicals and their precursors. Techniques to determine the actinic flux are also presented owing to the relevance of photolytically-initiated processes indoors. This review is also intended to provide pointers for those wanting to learn more about measurements of radicals indoors. KW - Criegee KW - peroxy KW - HONO KW - FAGE KW - CIMS KW - Laser-induced fluorescence KW - Luftreinhaltung Y1 - 2022 U6 - https://doi.org/10.1080/05704928.2022.2087666 SN - 0570-4928 VL - 57 IS - 7 SP - 580 EP - 624 PB - Informa UK Limited 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 - JOUR A1 - Herr, Caroline E. A1 - Brenner, Bernhard A1 - Thekoke, Jochen A1 - Nehr, Sascha T1 - Stand der Aktivitäten in den VDI – Arbeitsgruppen (Gemeinschaftsausschuss „Bioaerosole und Biologische Agenzien“) JF - Das Gesundheitswesen KW - Luftreinhaltung Y1 - 2017 U6 - https://doi.org/10.1055/s-0037-1602072 SN - 0941-3790 VL - 79 IS - 4 SP - 299 EP - 374 PB - Thieme ER - 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 - 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 - 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 - 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 - CHAP A1 - Nehr, Sascha T1 - Probleme in der Praxis der Geruchsbeurteilung – Handlungsfelder für die technische Regelsetzung T2 - Gerüchte in der Umwelt: Nürnberg, 15. und 16. November 2017 KW - Luftreinhaltung KW - Geruchsemission Y1 - 2017 SN - 0083-5560 VL - VDI-Berichte 2315 SP - 171 PB - VDI-Verlag ER - TY - CHAP A1 - Nehr, Sascha T1 - Probleme in der Praxis der Geruchsbeurteilung – Handlungsfelder für die technische Regelsetzung T2 - Gerüche in der Umwelt: Nürnberg, 15. und 16. November 2017 KW - Luftreinhaltung Y1 - 2017 SN - 978-3-18-092315-4 SN - 0083-5560 VL - VDI-Berichte 2315 SP - 171 EP - 180 PB - VDI Verlag CY - Düsseldorf ER - TY - JOUR A1 - Saffell, John A1 - Nehr, Sascha T1 - Improving Indoor Air Quality through Standardization JF - Standards N2 - Human beings experience a large fraction of their exposure to air pollutants in indoor environments. Air pollution is a large environmental health risk, and exposure to ambient air pollution and indoor air pollution contribute equally to the total number of fatalities worldwide. Although legislative authorities have established limit values for ambient outdoor air and stack emissions, there are inconsistent and variable national and regional limit values for gaseous substances and airborne particulate matter in the built environment (schools, homes, healthcare facilities, offices, and other public spaces). This lack of regulation is unsurprising, because indoor spaces are characterized by complex air chemistry, and their construction materials and types of activities vary significantly. The current understanding of indoor pollutants, including short-lived oxidants, degradation of VOCs, particle formation, and particle composition, is incomplete. It is necessary to identify and assess emerging pollutants and their toxicity, and to consider new consumer products and green construction materials and their impact on indoor air quality (IAQ). Learning from IAQ surveys and audit protocols, research methodologies should be regularized for cross-research comparisons. Some indoor air quality guidance and standards have been written, and several more are in development, with the international ISO 16000 series of indoor standards leading the way for improving indoor air data quality. The WHO has established some ambient air limit values which can mostly be translated into indoor limit values. The built environment needs to harmonize energy efficiency, thermal comfort and air quality standards and guidance. In this review, we discuss the next steps for improving international, regional and national standards and guidance, leading to better and more complete indoor air quality regulations. KW - indoor air quality KW - IAQ KW - air quality standards KW - air quality regulations KW - air quality guidance KW - indoor pollutants KW - IAQ survey KW - indoor air data quality KW - limit value KW - Luftreinhaltung Y1 - 2023 U6 - https://doi.org/10.3390/standards3030019 SN - 2305-6703 VL - 3 IS - 3 SP - 240 EP - 267 PB - MDPI ER - TY - JOUR A1 - Baus, Lukas A1 - Nehr, Sascha T1 - Potentials and limitations of direct air capturing in the built environment JF - Building and Environment N2 - This concept study presents an approach for resolving the trade-off between energy-efficient building operation and the provision of hygienically harmless indoor air quality. A novel coupling of HVAC-systems (heating, ventilation and air conditioning systems) with DAC-technology (direct air capturing technology) is proposed to separate CO2 in the exhaust air of buildings and recirculate the CO2-depleted air back into the building. In a mainly theoretical approach, the corresponding potentials and limitations of the novel HVAC/DAC-coupling in recirculation mode are evaluated. For that purpose, CO2-loads in the feed and exhaust air of four buildings located in Germany were measured using calibrated non-dispersive infrared (NDIR) sensors with pyroelectric detection principle. Subsequent numerical model simulations resort to typical meteorological data as well as building operation parameters grouped in different scenarios. The measurement and simulation results were assessed with regard to: (i) the unique possibilities of a HVAC/DAC-coupling in recirculation mode for the improvement of indoor air quality, (ii) the energy saving potentials through reduced air conditioning requirements enabled by a HVAC/DAC-coupling in recirculation mode, and (iii) the potential allocation of CO2 separated from building exhaust air for energetic and/or material reutilization in decentralized systems. In conclusion, a HVAC/DAC-coupling in recirculation mode can not only reduce the energy demand of buildings but also facilitates access to unutilized CO2-resources transported in the built environment and additionally offers the potential to improve indoor air quality. However, a suitable DAC module for operation in indoor air is not yet commercially available. KW - Direct air capturing KW - Indoor air quality KW - Energy-efficient ventilation KW - CO 2-Separation KW - HVAC KW - Circular economy KW - Luftreinhaltung Y1 - 2022 U6 - https://doi.org/10.1016/j.buildenv.2021.108629 SN - 0360-1323 VL - 208 PB - Elsevier ER - TY - JOUR A1 - Nehr, Sascha A1 - Duarte, Regina M. B. O. A1 - Almeida, Antoine S. A1 - Baus, Lukas A1 - Bergmann, Karl-Christian T1 - Assessing the relevance of allergenic pollen in indoor environments—current knowledge base and research needs JF - Allergo Journal International N2 - SummaryAirborne pollen allergens—a relevant component of bioaerosols and, therefore, of airborne particulate matter—are considered an important metric in air quality assessments. Although the measurement of airborne pollen allergen concentrations in outdoor environments (namely, in urban areas) has been recognized as a key environmental health indicator, no such obligation exists for indoor environments (dwellings or occupational settings). However, people spend most of their daily time (80–90%) indoors, where the majority of their exposure to air pollution, including pollen allergens, occurs. Nonetheless, the relative importance of airborne pollen allergen exposure indoors differs from outdoors because of differences in pollen loads, sources, dispersion, and degree of penetration from the outdoor surroundings, as well as the differences in the allergenic pollen profiles. In this brief review, we mined the literature over the last 10 years to summarize what existing measurements reveal about the relevance of airborne allergenic pollen in indoor environments. The research priorities on this topic are presented, highlighting the challenges and the motivations for obtaining pollen data in built environments which are key to understand the extent and mechanisms of human exposure to airborne pollen allergens. Thus, we provide a comprehensive assessment of the relevance of airborne allergenic pollen in indoor environments, highlighting knowledge gaps and research needs related to their health effects. KW - standardization strategies KW - pre-standards KW - success factors KW - Business Model Canvas KW - environmental impact KW - Luftreinhaltung Y1 - 2023 U6 - https://doi.org/10.1007/s40629-023-00251-y SN - 2197-0378 VL - 32 IS - 6 SP - 167 EP - 175 PB - Springer Nature ER -