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In WP3 (AeroEXCA), headed by HMGU, the expertise in Aerosol Exposure and Characterizing aerosol of the consortium is bundled. Comprehensive chemical and physical characterization of fresh and aged aerosols will be performed in order to unravel their chemical composition and changes upon aging. In addition to the application of high-end chemical/physical characterization of the exposure aerosol, innovative new aerosol mass spectrometric methods will be developed and applied, revealing the internal and external mixing within particle ensembles. HMGU, WIS and FZJ will contribute to WP3. Large Facilities of the Helmholtz International Laboratory in WP3 are the deep organic characterization Laboratory at HMGU featuring ultrahigh mass resolution mass spectrometry (FT-ICR) and special PM-analysis adapted high end chromatographic – mass spectrometric instruments. Furthermore, mobile on-line gas and particle phase mass spectrometric systems are available for joint research activities (HMGU and FZJ). These instruments represent the state of the art in terms of characterization of atmospheric aerosol and gas phase species. In WIS, high resolution time of flight aerosol mass spectrometer and aerodynamic aerosol classifier will be used to correlate between aging, chemical composition and density. Innovative air-liquid interface (ALI) aerosol exposure systems (2 different types and approaches) and approaches for human and murine lung cells, co-cultures and tissue models will be applied and further optimized. This includes the application of on-line aerosol enrichment and dose determination approaches. Crucial is the improvement in the practical realization of long-time and multiple ALI-cell exposure scenarios in order to increase the biological effect detection efficiency required for addressing the diluted chamber aged aerosol and ambient air directly. Large Facilities of the International Lab: The HMGU-developed mobile Exposure S2-biosafety laboratory HICE-MobiLab (HMGU) and 3 mobile automated ALI-cell exposure stations with in total 60 simultaneously exposable transwell positions (HMGU) will be transferred and used in the chamber and flow reactor aging experiments in FZJ and WIS in the joint experiments.

RESEARCH METHODOLOGY AND APPROACH OF AeroEXCA

The objective of WP3 is to characterize the fresh and aged aerosols and to develop and apply innovative and novel techniques in aerosol enrichment, air-liquid interface (ALI) cell exposure, as well as ALI exposure dose measurement. WP 3 will apply, improve and develop state-of-the-art chemical aerosol characterization techniques for health relevant aerosol parameters. In particular the transformation processes upon aging and atmospheric transformation are in the focus of interest. Source apportionment approaches utilizing the chemical signatures, which are specially addressing artificially aged chamber aerosols as well as ambient aerosols are refined and applied in WP3 as well. The following instrumental analytical methods are, among others, available in the consortium and will be applied for aerosol characterization: in situ derivatization thermal desorption multidimensional gas chromatography-mass spectrometry (DTD-GC-TOFMS) [1], ultra-high resolution mass spectrometry (FT-ICRMS/Orbitrap-MS) [2], and aerosol single particle TOF-mass spectrometry (ATOF) [3]. The molecular organic chemical composition and parameters such as thermo-optical properties of carbonaceous PM Fractions and soot will be considered as well. Furthermore indicator parameters for the identified, health-relevant aerosol fractions will be determined by comprehensive statistical approaches in cooperation with WP5. The characterization of the aged aerosols is directly linked to WP2.

Another challenge of WP3 is the optimization of ALI technology to allow long-term exposures with exposure times of > 24 h. This will be done by media circulation, aerosol enrichment approaches and PM-deposition enhancing methods based on thermophoretic and electrostatic forces in conjunction with the Vitrocell-Exposure approaches. By advancing the ALI-technique for longer exposure times the approach will be able to cope with the low PM-concentrations (~10 - 150 µg/m3) of ambient aerosols or realistically aged chamber aerosol (WP2). In addition to the mentioned measures more robust cell cultures and test approaches (including disease models and acute as well as sub-acute endpoints) will be addressed together with WP4. WP3 is operational from the beginning of the AeroHEALTH project.

This task is corroborated by research on deposition dose measurement and analytical methods directly inside the ALI-system (WP3) for achieving on-line information about the lung cell status und the exposing aerosol. Studies on a fluorescence-based reporter assay for reporting lung cell status shall provide in situ information on the induced biological effects. Europe's first mobile, field-deployable S2-biosafety laboratory (HICE-Mobilab) equipped with newest generation of mobile automated ALI-exposure-station systems with optimized exposure cells will be used for on-site lung cell ALI-exposure studies during the consortium wide measurement campaigns as well as for studies with the novel cell status monitoring devices.

[1] Orasche, J., et al. Atm. Chem. Phys. 11 (17): 8977-8993 (2011)
[2] Kourtchev, I., et al. Atm. Chem. Phys. 15(10): 5683-5695 (2015)
[3] Passig, J. et al., Anal. Chem. 89, 6341-6345 (2017)