<p>The aim of this thesis was to verify the indicated occurrence of acrylamide formation in heating of food, to identify factors affecting the formation, and to identify important sources of acrylamide exposure from food. As a prerequisite for the studies, gas- and liquid-chromatographic methods with mass spectrometric detection were developed for the analysis of acrylamide in food. The developed methods showed a high correlation coefficient (0.99), high sensitivity and reproducibility. Acrylamide was demonstrated to occur in heated food products, with unexpectedly high levels in potato products (up to mg/kg level in potato crisps) and in beetroot. The identity of acrylamide was confirmed by the developed methods. </p><p>With potato as a food model, different factors affecting the acrylamide formation were tested. It was shown that the addition of asparagine and fructose, as well as heating temperature and time had a large impact on the formation. Other factors affecting the acrylamide content were pH, addition of other amino acids apart from asparagine, protein and other reducing sugars. No significant effects were observed from addition of neither antioxidant nor radical initiators. It was discovered that acrylamide could be formed during heating of biological materials similar to food, also at temperatures below 100 ˚C. Furthermore, it was demonstrated that a fraction of acrylamide evaporates during heating, similar to conditions for cooking in household kitchens, and during dry matter determinations in laboratories (65-130 ˚C). This constitutes an earlier unobserved source of exposure to acrylamide.</p><p>The method for extraction of food was studied with regard to yield of acrylamide. It was shown that the yield at pH ≥12 increases 3 - 4 times compared to normal water extraction for some foods products. Extraction at acidic pH or with enzymatic treatment was also tested, showing no effect on yield.</p><p>In a study with mice the bioaviability of acrylamide extracted with the normal water extration and at alkaline pH was compared. It was shown that the extra acrylamide released at alkaline pH gave insignificant contributions to the in vivo dose, measured by hemoglobin adducts.</p>

The aim of this thesis was to verify the indicated occurrence of acrylamide formation in heating of food, to identify factors affecting the formation, and to identify important sources of acrylamide exposure from food. As a prerequisite for the studies, gas- and liquid-chromatographic methods with mass spectrometric detection were developed for the analysis of acrylamide in food. The developed methods showed a high correlation coefficient (0.99), high sensitivity and reproducibility. Acrylamide was demonstrated to occur in heated food products, with unexpectedly high levels in potato products (up to mg/kg level in potato crisps) and in beetroot. The identity of acrylamide was confirmed by the developed methods. With potato as a food model, different factors affecting the acrylamide formation were tested. It was shown that the addition of asparagine and fructose, as well as heating temperature and time had a large impact on the formation. Other factors affecting the acrylamide content were pH, addition of other amino acids apart from asparagine, protein and other reducing sugars. No significant effects were observed from addition of neither antioxidant nor radical initiators. It was discovered that acrylamide could be formed during heating of biological materials similar to food, also at temperatures below 100 ˚C. Furthermore, it was demonstrated that a fraction of acrylamide evaporates during heating, similar to conditions for cooking in household kitchens, and during dry matter determinations in laboratories (65-130 ˚C). This constitutes an earlier unobserved source of exposure to acrylamide. The method for extraction of food was studied with regard to yield of acrylamide. It was shown that the yield at pH ≥12 increases 3 - 4 times compared to normal water extraction for some foods products. Extraction at acidic pH or with enzymatic treatment was also tested, showing no effect on yield. In a study with mice the bioaviability of acrylamide extracted with the normal water extration and at alkaline pH was compared. It was shown that the extra acrylamide released at alkaline pH gave insignificant contributions to the in vivo dose, measured by hemoglobin adducts.

The health effects of particulate air pollution and the evaluation of mitigation efforts to address them have been focused in the past on measurements of bulk mass concentrations of aerosol particles (particulate matter or PM) at fixed locations instead of more traffic-related PM such as black carbon (BC). A more appropriate investigation of the spatial and temporal variabilities of these pollutants is necessary to effectively estimate realistic pedestrian exposure. In this work, three novel scientific contributions are presented with an overarching goal of quantifying the influence of environmental factors on the spatial and temporal distributions of BC and PM2.5 (all particles smaller than 2.5 micrometers) in urban areas. Mass concentrations of BC and PM2.5 were obtained with a mobile platform called the “aerosol backpack”. With this tool, strategic mobile measurement field campaigns were conducted at multiple sites in four countries to achieve the scientific objectives of this work. First, a concept was developed to optimize the mobile measurement strategy for obtaining high-quality data for scientific analyses including a traceable way to reconstruct and calculate PM2.5 mass concentrations from an optical particle size spectrometer. Second, an entire investigation was done on the field performance of the most widely-used portable absorption photometer for measuring BC mass concentrations, the AE51. Results show that these instruments are robust and reliable across different environments. Third, a statistical approach based on a Bayesian distributional model was developed and refined to suitably analyze mobile measurement datasets and extract reliable information. Through this model, the differences between the effects of human activities and other environmental factors on BC and PM2.5 have been quantified. These results quantitatively confirm that spatial and temporal characteristics related to human activities have stronger effects on the variability of the BC mass concentration than on the regulated PM2.5 – consequently, having more influence on pedestrian exposure. This study highlights the importance of high data quality for mobile measurements to make them useful in exposure assessment, particularly to pollutants that are highly variable in space. Finally, this study contributes to the growing evidence of the importance of including more traffic-related pollutants to monitor air quality in urban areas and create appropriate mitigation strategies to combat the adverse health effects of air pollution.:Table of Contents Bibliographic Description .................................................................................................. i Bibliografische Beschreibung ........................................................................................... ii 1. Introduction ................................................................................................................... 1 1.1 Black carbon ....................................................................................................... 2 1.2 Mobile measurements ........................................................................................ 5 1.3 Objectives ............................................................................................................... 6 2. Methodology ................................................................................................................. 9 2.1 TROPOS Aerosol backpack ................................................................................... 9 2.1.1 Instrumentation .............................................................................................. 10 2.2 Mobile measurement strategy ........................................................................... 12 2.3 Phase 1 – Pilot studies .......................................................................................... 12 2.3.1 MACE-2015, Manila Philippines (Master thesis) ......................................... 13 2.3.2 Saxony Soot Project 2016, Leipzig and Dresden, Germany .......................... 15 2.4 Phase 2 – Optimization of MM and quality assurance ......................................... 18 2.4.1 CARE-2017, Rome, Italy .............................................................................. 18 2.4.2 Other datasets ................................................................................................. 19 2.5 Phase 3 – Data analysis ......................................................................................... 20 2.5.1 Statistical model: lognormal distributional regression .................................. 21 3. Results and Discussion ............................................................................................... 27 3.1 First publication .................................................................................................... 27 3.1.1 Methodology for high-quality mobile measurement with focus on black carbon and particle mass concentrations ............................................................................ 27 3.2 Second publication ................................................................................................ 45 3.2.1 Performance of microAethalometers: Real-world field intercomparisons from multiple mobile measurement campaigns in different atmospheric environments 45 3.3 Third Publication .................................................................................................. 73 iv 3.3.1 Pedestrian exposure to black carbon and PM2.5 emissions in urban hotspots: New findings using mobile measurement techniques and flexible Bayesian regression models .................................................................................................... 73 4. Summary and Conclusions ....................................................................................... 101 5. Outlook ..................................................................................................................... 107 Appendix ....................................................................................................................... 109 A.1 Publications included in the Doctoral Thesis and Author’s contributions ......... 109 A.2 Other Publications as First Author and Co-author during PhD ......................... 111 A.3 PhD Committee .................................................................................................. 113 A.4 Supervision Committee ...................................................................................... 114 List of Figures ............................................................................................................... 115 List of Tables ................................................................................................................ 116 Abbreviations ................................................................................................................ 117 Bibliography ................................................................................................................. 119 Acknowledgement ........................................................................................................ 129 / Die gesundheitlichen Auswirkungen der Luftverschmutzung durch Feinstaub und die Bewertung von Maßnahmen zu ihrer Eindämmung konzentrierten sich bisher auf Messungen der Massenkonzentration von Aerosolpartikeln (PM; Particulate Matter) an festen Standorten und nicht auf verkehrsbedingte Aerosolpartikel wie z. B. Ruß (BC; Black Carbon). Eine zielgerichtete Untersuchung der räumlichen und zeitlichen Variabilität dieser Schadstoffe ist notwendig, um die realistische Exposition von Fußgängern effektiv abzuschätzen. In dieser Arbeit werden drei neue wissenschaftliche Ansätze mit dem übergreifenden Ziel vorgestellt, den Einfluss von Umweltfaktoren auf die räumliche und zeitliche Verteilung von BC und PM2,5 in städtischen Gebieten zu quantifizieren. Die Massenkonzentrationen von BC und PM2,5 (alle Partikel kleiner 2,5 Mikrometer) wurden mit einer mobilen Plattform, dem Aerosol-Rucksack, gemessen. Damit wurden strategische mobile Messkampagnen an mehreren Standorten in verschiedenen Ländern durchgeführt, um die wissenschaftlichen Ziele dieser Arbeit zu erreichen. Dazu wurde zunächst ein Konzept zur Optimierung der mobilen Messstrategie entwickelt, um qualitativ hochwertige Daten für wissenschaftliche Analysen zu erhalten, einschließlich einer nachvollziehbaren Methode zur Rekonstruktion und Berechnung von PM2.5-Massekonzentrationen aus Messungen mit einem optischen Partikelgrößenspektrometer. Zweitens wurde die Leistungsfähigkeit der am häufigsten verwendeten tragbaren Absorptionsphotometers zur Messung der BCMassekonzentration unter realistischen Bedingungen untersucht. Diese Ergebnisse zeigen, dass die verwendeten Geräte in den unterschiedlichsten Umgebungen robust und zuverlässig einsetzbar sind. Drittens wurde ein statistischer Ansatz entwickelt und angepasst, um mobile Messdatensätze in geeigneter Weise zu analysieren und weitere nützliche Informationen zu gewinnen. Mithilfe dieses Modells wurden die Unterschiede zwischen den Auswirkungen menschlicher Aktivitäten und anderer Umweltfaktoren auf BC und PM2,5 quantifiziert. Diese Ergebnisse bestätigen quantitativ, dass räumliche und zeitliche Merkmale im Zusammenhang mit menschlichen Aktivitäten stärkere Auswirkungen auf die Variabilität der BC-Massekonzentration haben als auf die regulierte PM2,5-Konzentration - und folglich auch einen größeren Einfluss auf die Exposition von Fußgängern. Diese Studie unterstreicht die Bedeutung hoher Datenqualität bei mobilen Messungen zur Expositionsabschätzung, insbesondere bei Schadstoffen, die räumlich sehr variabel sind. Insbesondere trägt diese Studie dazu bei, die Notwendigkeit hervorzuheben, in städtischen Gebieten mehr verkehrsbedingte Luftschadstoffe in die Überwachung der Luftqualität einzubeziehen. Darüber hinaus sollen geeignete Strategien, zur Bekämpfung der gesundheitsschädlichen Auswirkungen der Luftverschmutzung, entwickelt werden.:Table of Contents Bibliographic Description .................................................................................................. i Bibliografische Beschreibung ........................................................................................... ii 1. Introduction ................................................................................................................... 1 1.1 Black carbon ....................................................................................................... 2 1.2 Mobile measurements ........................................................................................ 5 1.3 Objectives ............................................................................................................... 6 2. Methodology ................................................................................................................. 9 2.1 TROPOS Aerosol backpack ................................................................................... 9 2.1.1 Instrumentation .............................................................................................. 10 2.2 Mobile measurement strategy ........................................................................... 12 2.3 Phase 1 – Pilot studies .......................................................................................... 12 2.3.1 MACE-2015, Manila Philippines (Master thesis) ......................................... 13 2.3.2 Saxony Soot Project 2016, Leipzig and Dresden, Germany .......................... 15 2.4 Phase 2 – Optimization of MM and quality assurance ......................................... 18 2.4.1 CARE-2017, Rome, Italy .............................................................................. 18 2.4.2 Other datasets ................................................................................................. 19 2.5 Phase 3 – Data analysis ......................................................................................... 20 2.5.1 Statistical model: lognormal distributional regression .................................. 21 3. Results and Discussion ............................................................................................... 27 3.1 First publication .................................................................................................... 27 3.1.1 Methodology for high-quality mobile measurement with focus on black carbon and particle mass concentrations ............................................................................ 27 3.2 Second publication ................................................................................................ 45 3.2.1 Performance of microAethalometers: Real-world field intercomparisons from multiple mobile measurement campaigns in different atmospheric environments 45 3.3 Third Publication .................................................................................................. 73 iv 3.3.1 Pedestrian exposure to black carbon and PM2.5 emissions in urban hotspots: New findings using mobile measurement techniques and flexible Bayesian regression models .................................................................................................... 73 4. Summary and Conclusions ....................................................................................... 101 5. Outlook ..................................................................................................................... 107 Appendix ....................................................................................................................... 109 A.1 Publications included in the Doctoral Thesis and Author’s contributions ......... 109 A.2 Other Publications as First Author and Co-author during PhD ......................... 111 A.3 PhD Committee .................................................................................................. 113 A.4 Supervision Committee ...................................................................................... 114 List of Figures ............................................................................................................... 115 List of Tables ................................................................................................................ 116 Abbreviations ................................................................................................................ 117 Bibliography ................................................................................................................. 119 Acknowledgement ........................................................................................................ 129