Hazards associated with air pollution motivate the search for technologies capable of monitoring individual exposure to gaseous pollutants and particulate matter (PM). A Low-cost Optical Particle Counter (OPC), costing less than 50 USD, is an example of such technologies. Currently, OPCs are widely used to measure the concentration of particle matter in ambient air. While these low-cost air quality sensors are widely available, the accuracy and precision of these devices is highly uncertain. Consequently, the purpose of this thesis is to present an analytical model of two generic, low-cost OPCs based on the Laws of Conservation of Mass, Momentum, and Energy. These models utilize Mie scattering theory and Computational Fluid Dynamics models to quantify uncertainty and accuracy in low-cost OPCs based first principles. Modeling results indicate that the measurement of forward-scattered light may dramatically increase the accuracy of low-cost OPCs. These results also indicate that careful attention must be placed on the design of sensor flow passages so as to most efficiently transport particles to the scattering volume where they may be detected. A combination of careful attention to photodetector placement in the forward scattering regime as well as efficient transport to the scattering volume may increase low-cost OPC accuracy by magnitudes of order.

Der Leitfaden beinhaltet die umfangreichen Erkenntnisse und Erfahrungen zur Verbesserung der Luftqualität seit dem ersten sächsischen Luftreinhalteplan im Jahr 2003. Er informiert über die gesetzlichen Grundlagen und die Anforderungen zur Aufstellung von Luftreinhalteplänen. Der Bericht dokumentiert die Standorte der Luftmessstationen, die Messparameter und Messtechnik und erläutert die mathematische Modellierung der Messwerte. Neben der zeitlichen Entwicklung der Luftqualität werden Maßnahmen zur Erreichung einer guten Luftqualität vorgestellt. Die Luftreinhalteplanung in Sachsen wird eingeordnet in den erreichten Stand in Deutschland und der EU.

Feinstaub kleiner 2,5 Mikrometer (PM2,5) ist ein neuer Parameter zur Beurteilung der Luftqualität. Ziel- und Grenzwerte für PM2,5 wurden mit der Novellierung der EU-Luftqualitätsrichtlinie 2008 zusätzlich zu denen für Feinstaub kleiner 10 Mikrometer (PM10) festgelegt. Die größten sächsischen Quellen für PM2,5 sind Straßenverkehr und Kleinfeuerungsanlagen für feste Brennstoffe. Industrie und Landwirtschaft sind weitere Quellen. Der Anteil von PM2,5 am PM10 ist bei den Jahresmittelwerten stabil. Deshalb können für die Beurteilung der Luftqualität an geringer belasteten Orten auch die bisher gemessenen PM10-Daten mit herangezogen werden. Der ab 2015 geltende Grenzwert für PM2,5 ist in Sachsen bisher nicht überschritten worden. Die erstmals für die ganze Fläche Sachsens modellierte Belastung hat für die Prognosejahre 2015 und 2020 ebenfalls keine Hinweise auf Grenzwertüberschreitungen ergeben. Das nationale Ziel für die Minderung der durchschnittlichen Exposition der Bevölkerung bis 2020 stellt noch einmal höhere Anforderungen an die Luftqualität.

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

Thesis: M.S., Massachusetts Institute of Technology, Sloan School of Management, 1977 / Includes bibliographical references. / by Michael K. Martin. / M.S. / M.S. Massachusetts Institute of Technology, Sloan School of Management

Air quality forecasts are of great value since several pollutants in our environment effect both human health, global climate, vegetation, crop yields, animals, materials and acidification of forests and lakes. Air-quality forecasts help to make people aware of the presence and the quantity of pollutants, and give them a chance to protect themselves, their business and the Earth. Many different air-quality models are in daily use all over the world, providing citizens with forecasts of air quality and warnings of unhealthy air quality if recommended highest concentrations are exceeded. This study adapts the WRF meteorological model (Weather research and Forecasting model) to be a driver of the CMAQ air-quality model (models-3 Community Multiscale Air Quality model). Forecasts of ozone and nitrogen dioxide concentrations from this coupled WRF/CMAQ modelling system are tested against observed data during a four-day period in May, 2006. The Lower Fraser Valley study area is a fertile valley surrounded by mountain chains in southwest British Columbia, Canada. The valley stretches from the Pacific coast eastwards towards the Rocky Mountains. This valley hosts more than 2 million people and it is west Canada’s fastest growing region. The Lower Fraser Valley holds a big city, Vancouver, several suburbs, numerous industries and a widespread agricultural production. During the analysed four-day period in May, a synoptic high-pressure built over the region, favoring high concentrations of pollutants as ozone and nitrogen dioxide. The created WRF/CMAQ model forecasted an acceptable magnitude of nitrogen dioxide but the daily variations are not recreated properly by the model. The WRF/CMAQ model forecasts the daily variation of ozone in a satisfying way, but the forecasted concentrations are overestimated by between 20 and 30 ppb throughout the study. Factors that could contribute to the elevated ozone concentrations were investigated, and it was found that the weather forecasting model WRF was not generating fully reliable meteorological values, which in turn hurt the air-quality forecasts. As the WRF model usually is a good weather forecasting model, the short spin-up time for the model could be a probable cause for its poor performance. / Prognoser över luftkvaliteten är mycket värdefulla, då flera luftföroreningar i vår närmiljö påverkar människans hälsa, det globala klimatet, vegetation, djur, material och bidrar till försurning av skog och vattendrag. Luftkvalitetsprognoser gör människan mer medveten om närvaron av luftföroreningar och i vilken mängd de finns. De ger människan en chans att vidta skyddsåtgärder för att skydda sig själv, sitt eventuella levebröd, och Jorden. Många olika luftkvalitetsmodeller används idag dagligdags över hela världen och förser invånare med prognoser för luftkvaliteten och varningar om koncentrationerna av föroreningar överstiger rekommenderade värden. I denna studie används väderprognosmodellen WRF (Weather Research and Forecasting model) för att driva luftkvalitetsmodellen CMAQ (models-3 Community Multiscale Air Quality model). Prognoser av ozon- och kvävedioxidhalterna i luften från den kopplade WRF/CMAQ modellen analyseras mot observerade data under en fyra dagars period i maj, 2006. Studieområdet Lower Fraser Valley är en bördig dalgång som är omgiven av bergskedjor i sydvästra British Columbia, Kanada. Dalen sträcker sig från Stilla havskusten och österut mot Klippiga bergen. I denna dalgång bor mer än 2 miljoner människor och det är västra Kanadas snabbast växande region. Lower Fraser Valley rymmer en storstad, Vancouver, flera förorter, många industrier och även stora jordbruksområden. Den fyra dagars period i maj som analyseras karaktäriseras av ett högtrycksbetonat synoptiskt väderläge med lokala variationer, vilka tillsammans är gynnsamma för att uppmäta höga koncentrationer av luftföroreningar som ozon och kvävedioxid. Den skapade WRF/CMAQ modellen prognostiserar godtagbar magnitud hos kvävedioxid men den dagliga variationen återskapas inte av modellen. Modellen prognostiserar den dagliga variationen av ozonkoncentration på ett tillfredsställande sätt, men storleksmässigt ligger koncentrationerna en faktor 20-30 ppb för högt rakt av under hela studien. Kringliggande faktorer som kan påverka koncentrationen ozon studeras närmare och det framkommer att den meteorologiska prognosmodellen WRF inte genererar fullt tillförlitliga värden för en rättvisande luftkvalitetsprognos. Då WRF modellen vanligtvis är en bra prognosmodell kan den korta initialiseringstiden för modellen vara en trolig orsak till dess otillräckliga prestation.

Measuring air pollution emissions from agricultural activities is usually difficult because of their large area and variability. Traditional air quality sensors, called point samplers, measure conditions in one location, which may not adequately measure a plume. Remote sensors, instruments that measure pollution along a line rather than at a single point, are better able to measure conditions around large areas. This dissertation reports on four agricultural air emissions studies that used both point and remote sensors for comparison. The methods used to calculate the emissions are based on previous work and are further developed in these studies. In particular, an atmospheric dispersion model was developed and tested that can account for a particle behaving different than the surrounding gas due to gravity and inertia and depositing out of the flow. Particulate matter (PM) emissions values are reported for two agricultural tillage conservation management practices (CMPs)and the corresponding traditional tillage methods in order to determine how well the CMP reduces emissions. In addition, gas-phase ammonia (NH3) emissions for a dairy operation and PM emissions from a feedlot operation are reported. These studies can help us better measure emissions from agricultural operations and understand how much air pollution is being emitted.

Policy-makers, transportation researchers, and activists often assume that traffic congestion mitigation results in reduced vehicle emissions without proper justification or quantification of the benefits. If congestion mitigation is going to be tied to air quality goals, a better understanding of the impacts of traffic congestion on motor vehicle emissions is needed. This research addresses that need by investigating under which circumstances the commonly held assumption linking congestion mitigation to emissions reductions is valid. We develop and apply a mathematical framework to study the trade-offs between vehicle efficiency and travel demand that accompany travel speed changes. While the exact relationships among emissions, travel speed, and travel demand vary with location and pollutant, several consistent results arise. The potential for marginal emissions rate reductions through average travel speed adjustments is small for speeds between about 25 and 70 mph. Emissions rate sensitivity to speed increases with the fraction of heavy-duty vehicles and for certain pollutants (gaseous hydrocarbons and particulate matter), and decreases with the fraction of advanced-drivetrain vehicles, such as electric and gas-electric hybrid vehicles. But travel volume is also a key consideration for the total emissions impacts of congestion and congestion mitigation. While travel speed increases are generally expected to increase efficiency, they are also expected to increase vehicle travel volume as a result of induced demand. To explore efficiency and volume trade-offs we look at emissions break-even conditions for average speed and travel demand elasticity. Depending on the pollutant and the vehicle fleet, total emissions are only expected to decrease with increasing travel speed for initial conditions of both low demand elasticity and low average speed. Thus, higher levels of congestion do not necessarily increase emissions, nor will congestion mitigation inevitably reduce emissions. This result includes projects that seek to increase vehicle throughput from existing roadway supply through better traffic management and operations. Congestion mitigation through reduced vehicle volumes, on the other hand, presents the opportunity for additive emissions benefits through efficiency improvements and total Vehicle Miles Traveled (VMT) reductions. Comparing capacity-based congestion mitigation strategies with alternative emissions reduction strategies we show that where emissions reductions are possible through speed increases, the emissions benefits are likely to be more easily and cost-effectively attained by other strategies. A sketch analysis of vehicle-class segregated facilities shows that truck-only lane strategies consistently out-perform general-purpose/mixed-flow lane strategies in terms of emissions reductions. An analysis of several congestion-related performance measures shows that for reflecting emissions impacts, VMT is an essential component of performance. Thus, alternative congestion metrics such as total/excess travel distance and travel time are preferable emissions performance indicators to speed or distance-normalized delay. The Travel Time Index, in particular, poorly reflects emissions changes on congested roadways. This thesis offers several original contributions to the body of knowledge regarding congestion and emissions. First, it describes a parsimonious conceptual framework for assessing the effect of congestion on emissions. Then from that framework, several simple and original equations are presented which can be used for sketch-level planning to estimate emissions impacts from congestion mitigation. Finally, application of the framework provides quantitative support for the decoupling of congestion and emissions mitigations.

With increasing knowledge about the indoor climate in recent years, preventive methods to avoid health problems caused by deficient building performance may become preferable to reactive methods. Benefits from preventive actions have been suggested for late building design phases, construction, and building operations, however, few data are available that demonstrate the benefits of preventive actions in early planning phases. In a case study, expected building performance in respect to indoor air quality and thermal conditions in a large judicial facility in North America was evaluated retrospectively at the end of the schematic design and substantial completion phases. A process for evaluation of building performance at schematic design is developed from existing procedures for building diagnostics in operating buildings. Criteria for evaluation of expected building environmental quality at schematic design as available from standards and guidelines are presented. The results of the study show that building diagnostics at schematic design can be an effective mean of prevention of occupant health problems. Further findings indicate that the assurance of indoor environmental quality can be improved, if the criteria for expected building performance are defined and complied with from early on. It is concluded that implementation of building diagnostics in early project phases can reduce the likelihood of adverse health effects in operating buildings. / Master of Science

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology; and, (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1966. / Includes bibliographical references (leaves 49-53). / Surface ozone concentrations were measured in the Greater Boston area from November, 1964 to December, 1965. Ozone was monitored continuosly using a Mast microcoulombmetric sensor. A chromium trioxide filter was fitted to the air inlet of the sensor in order to remove negatively interfering sulphur dioxide. Daily ozone concentrations near the surface varied from somewhat greater than 10 to less than 1 pphm by volume. The highest concentrations occurred in late spring while the lowest concentrations occurred in the winter. Such a seasonal variation would be expected if the ozone had arrived in the troposphere from the lower stratosphere. The concentration of ozone during the spring and early summer showed a much greater variability from day to day than was exhibited during the fall and winter months. / by Donald Allen Widen. / M.S.