Beginning in March 1999 at Georgia Institute of Technology, the ASACA (Assessment of Spatial Aerosol Composition in Atlanta) program has provided PM₂. ₅ concentration and speciation using particle concentration monitoring in and around metropolitan Atlanta. Since 1999, three of the ASACA sites have collected PM₂. ₅ in an urban setting: Fort McPherson (FT, SW), South Dekalb (SD, SE), and Tucker (TU, NE). In January 2007, TU was retired and Fire Station 8 (FS8, NE) was employed as the new urban site. Starting in 2002, PM₂. ₅ concentrations have also been characterized at a rural site, Fort Yargo (YG). Water-soluble ionic species and carbonaceous species concentrations are collected daily on filters using a three-channel particulate composition monitor (PCM). From 1999 to 2008, average PM₂. ₅ concentrations range from 12.9 µg/m3 at YG to 15.4 µg/m3 at TU. Sulfate and organic matter are the main components of Atlanta PM, contributing around 26% and 31% respectively to PM mass. Overall ASACA data quality increased from around 5 in 1999 to a value of 9 in 2005. Seasonal PM data quality appears to be significantly affected by volatility of secondary aerosol species during warm months because ionic data quality regularly decreases in the summer. PM is more sensitive to total sulfate concentration than nitrate and ammonia year-round.

The following thesis titled, Atlanta Automotive Particulate Matter Exposure and Evaluation, presents data obtained as a part of a joint project with Emory University, Rollin's School of Public Health. The Atlanta Commuters Exposure (ACE) Study uses both real-time and time-integrated sampling techniques for ambient aerosol concentrations. The ACE study is unique in that it will correlate the ambient aerosol concentrations with the concurrent health measurements. The primary objective of this thesis is to measure the concentration, size distribution and the chemical composition of PM2.5 inside the vehicle cabin for several commuters. The vehicles followed a scripted route along roadways in the Atlanta metropolitan region during periods of peak traffic volume, while the compact air sampling package of both real-time and time-integrated instruments recorded data. Real-time measurements for Particulate Matter (PM) were made using compact Optical Particle Counters (OPC), a Condensation Particle Counter, and a MicroAethalometer. The time-integrated measurements for Elemental Carbon (EC), Organic Carbon (OC), Water Soluble Organic Carbon (WSOC), particulate elemental concentrations, and speciated organics required filter collection methods. Thus a compact air-sampling package was created to combine both sets of real-time and time-integrated instruments. The following results are presented for the first four commutes. The framework for analyzing and presenting results is developed, and will be used for future commutes.

Both long-term and short-term exposure to fine particulate matter (PM2.5) has been shown to increase the rate of respiratory and cardiovascular illness, premature death, and hospital admissions from respiratory causes. It is important to understand what contributes to ambient PM2.5 level to establish effective regulation, and air quality model can provide guidance based on the best scientific understanding available. However, PM2.5 simulations in air quality models have often found performance less than desirable, particularly for organic carbon levels. Here, some of major shortcomings of current air quality model will be addressed and improved by using CMAQ, receptor models, and regression analysis. Detailed source apportionment of PM2.5 performed using the CMAQ-tracer method suggests that wood combustion and mobile sources are the largest sources of PM2.5, followed by meat cooking and industrial processes. Biases in emission estimates are investigated using tracer species, such as organic molecular markers and trace metals that are used in receptor models. Comparison of simulated and observed tracer species shows some consistent discrepancies, which enables us to quantify biases in emissions and improve CMAQ simulations. Secondary organic aerosol (SOA) is another topic that is investigated. CMAQ studies on organic aerosol usually underestimate organic carbon with larger than a 50% bias. Formation of aged aerosol from multigenerational semi-volatile organic carbon is added to CMAQ, significantly improving performance of organic aerosol simulations.

The rapid rising anthropogenic emissions driven by economic growth over China documented by satellite observations and bottom-up inventories have led to severely degraded air quality, and also have been suggested to be linked to the recent upward trends of tropospheric O₃ over the regions downwind of China. Multi-scale modeling analyses facilitated by ground-level, aircraft and satellite observations have been conducted to understand the atmospheric chemistry over China. Analyses using a 1-D photochemical model constrained by measurements at Beijing in August of 2007 suggest that reactive aromatic VOCs are the major source (~75%) of peroxy acetyl nitrate (PAN). Detailed radical budget analyses reveal the very fast ROₓ (OH + HO₂ + RO₂) production, recycling and destruction driven by VOC oxidation and heterogeneous processes. Photoenhanced aerosol surface uptake of NO₂ is found to be the predominant source of nitrous acid (HONO) during daytime (~70%). 3-D regional modeling analyses of tropospheric vertical column densities of glyoxal (CHOCHO) from SCIAMACHY show that anthropogenic emissions of aromatic VOCs are substantially underestimated (by a factor of 5 - 6, regionally varied) over China. Such an underestimation is the main cause of a large missing source of CHOCHO over the region in current global models, and could also partly explain the underestimation of organic aerosols in previous modeling studies.

As building codes and green building programs require tighter home construction, the need for outdoor air ventilation to improve indoor air quality increases. Major improvements in building envelopes and duct systems have led to decreases in heating and cooling loads causing fewer HVAC system run-time hours, and increasing the probability for air stagnation within homes with poor outdoor air ventilation. ASHRAE Standard 62.2 quantifies the amount of whole-house ventilation required based on the number of occupants and the square footage of conditioned space, but leaves the design of the ventilation system up to the mechanical engineer or HVAC contractor. In 2010, ASHRAE began requiring flow testing for confirmation of outdoor air ventilation rates, yet few municipalities and green building programs have adopted the new standard. Builders in mixed-humid climates are forced to balance the need for outdoor air ventilation with the upfront costs for mechanical ventilation systems, and the potential for increased humidity loads and energy costs associated with mechanical ventilation strategies. One common solution employed in the southeastern United States involves a central fan integrated supply (CFIS) ventilation system controlled with an air-cycler for minimum run-time to meet ASHRAE Standard 62.2. While this system has been tested and proven to meet design ventilation rates, those tests were often conducted on homes constructed by well trained builders receiving strong oversight from building scientists and the design ventilation rates were not always ASHRAE compliant. The following report analyzes whether the CFIS ventilation system with air-cycler controller provides ventilation meeting ASHRAE Standard 62.2 when employed by builders with minimal training and support.

Four receptor models and a chemical transport model were used to quantify the sources of PM2.5 impacting the St. Louis Supersite (STL-SS) between June 2001 and May 2003. The receptor models utilized two independent datasets, one that included ions and trace elements and a second that incorporated 1-in-6 day organic molecular marker data. Since each source apportionment (SA) technique has its own limitations, this work compared the results of five different SA approaches to better understand the biases and limitations of each. The source impacts predicted by these five models were then integrated into an ensemble-trained SA methodology. The ensemble method offered several improvements over the five individual SA techniques. Primarily, the ensemble method calculated source impacts on days when individual models either did not converge to a solution or did not have adequate input data to develop source impact estimates. Additionally, the ensemble method resulted in fewer days on which major emissions sources (e.g., secondary organic carbon and diesel vehicles) were estimated to have either a zero or negative impact on PM2.5 concentrations at the STL-SS. When compared with a traditional chemical mass balance (CMB) approach using measurement-based source profiles (MBSPs), the ensemble method was associated with better fit statistics, including reduced chi-squared values and improved PM2.5 mass reconstruction. A comparison of the different modeling techniques also revealed some of the subjectivities associated with applying specific SA models to the STL-SS dataset. For instance, positive matrix factorization (PMF) results were very sensitive to both the fitting species and number of factors selected for the analysis, whereas source impacts predicted in CMB were sensitive to the selection of source profiles to represent local metals processing emissions. Additionally, the different SA approaches predicted different impacts for the same source on a given day, with correlation coefficients ranging from 0.03 to 0.66 for gasoline vehicle, -0.51 to 0.85 for diesel vehicles, -0.29 to 0.86 for dust, -0.34 to 0.76 for biomass burning, 0.22 to 0.72 for metals processing, and -0.70 to 0.68 for secondary organic carbon. These issues emphasized the value of using several different SA techniques at a given receptor site, either by comparing source impacts predicted by different models or by utilizing an ensemble-trained SA technique.

Ein mobiler Aerosolstandard für ultrafeine Partikel wurde als neue Möglichkeit zur Qualitätskontrolle für innovative Umweltmessungen in Luftgütemessnetzen entwickelt. Die Bestimmung der Anzahl ultrafeiner Partikel in Ergänzung zur Überwachung von Feinstaub PM10 oder PM2.5 eröffnet neue Möglichkeiten, die Luftqualität zukünftig besser beurteilen zu können. Ultrafeine Partikel sind ein zweckmäßiger Indikator, um z. B. die positive Wirkung einer Umweltzone in Luftreinhalteplänen nachzuweisen.

Die Sondermessung in Riesa wurde von September 2008 bis August 2009 - die Bestimmung von Dioxinen, Furanen und polychlorierten Biphenylen im Staubniederschlag noch bis Dezember 2009 - durchgeführt. Sie diente zur Überprüfung der berechneten Immissionssituation für Feinstaub <10 μm (PM10) und Stickstoffdioxid (NO2) sowie zur Überprüfung des Einflusses der Elbe-Stahlwerke Feralpi GmbH (ESF) auf die Luftqualität in Riesa. Die auf die Messung folgende Modellierung der Luftqualität im Riesa ergab die höchsten Konzentrationen von PM10 im Gewerbegebiet. Die höchsten NO2-Konzentrationen treten entlang der Hauptverkehrsstraßen auf. Grenzwertüberschreitungen wurden an Straßenabschnitten mit Wohnbebauung nicht festgestellt. Die berechneten Immissionskonzentrationen stimmen gut mit den gemessenen überein. Die Abweichungen betragen jeweils ca. 10 % für den Jahresmittelwert von PM10 bzw. NO2. Sie liegen damit unter den von der EU-Richtlinie (2008/50/EG) geforderten Werten. Bei den Messungen der nachfolgenden Luftschadstoffe wurden keine Überschreitungen bei Grenz- und Zielwerten festgestellt: - PM10 - NO2 - Blei, Cadmium und Arsen im PM10 - Staubniederschlag - Blei, Cadmium und Arsen im Staubniederschlag. Der Einfluss der typischen Emissionen eines Stahlwerkes, wie Blei und Zink, aber auch Cadmium und Eisen, ist jedoch deutlich erkennbar. Bei Dioxinen, Furanen und dioxinähnlichen polychlorierten Biphenylen im Feinstaub PM 10 und im gasförmigen Zustand wird der vom Bund/Länderausschuss für Immissionsschutz (LAI) 2004 emp-fohlene Zielwert für die langfristige Luftreinhalteplanung (150 fg TE/m3) sicher eingehalten. Das Jahresmittel in Riesa lag bei 35 fg TE/m3. Der Zielwert für die Deposition (4 pg TE/(d*m2) dagegen wird in Riesa - wie auch an anderen Orten in Deutschland - überschritten. Die Mittelwerte über die Probenahmezeit von 16 Monaten an den vier Messpunkten lagen zwischen 5,5 und 14,7 pg TE/(d*m2). Die polychlorierten Biphenyle hatten daran einen maßgeblichen Anteil. Als wesentliche Quelle wurde die Verarbeitung des Schrotts, insbesondere die Schredderleichtfraktion und die Nichteisenmetalle, ermittelt. Die höheren Konzentrationen sind auf das unmittelbare Anlagenumfeld beschränkt und nehmen mit zunehmender Entfernung von der Quelle rasch ab. Am Friedrich-Ebert-Platz werden bereits Konzentrationen erreicht, die sich von denen der Vergleichsmessung im städtischen Hintergrund an der Station Chemnitz-Mitte kaum noch unterscheiden.

<p>In this thesis the sink-effect in indoor materials wasstudied using mathematical modelling and experimental studies.The sink-effect is a concept which is commonly used tocharacterise the ability of different indoor materials to sorbcontaminants present in the indoor air. The sorption process ismore or less reversible, i.e. molecules sorbed in materials athigh contaminant concentrations may again be desorbed at lowerconcentrations. Knowledge of the sorption capacity of materialsand the rate at which sorption and desorption takes place is offundamental importance for mathematical simulation of indoorair quality. The aim of this work is to contribute withknowledge about how the sink-effect can be described inmathematical terms and how the interaction parametersdescribing the sorption capacity and sorption/desorptionkinetics can be determined. The work has been of amethodological nature. The procedure has been to set upphysically sound mathematical models of varying complexity andto develop small-scale chamber experiments. Two differentdynamic chamber methods have been used. One is based on amodified standard FLEC-chamber while the other uses a chamberwith two compartments, one on each side of the material. The"twin-compartment" method was designed due to the observationthat the contaminant readily permeated straight through theselected materials, which resulted in uncontrolled radiallosses in the FLEC-chamber. In order to be useful forcomparison between experiments and calculations and parameterfitting, the boundary conditions in the chambers must beprecisely known and controlled. This matter has shown to be themost crucial and difficult problem in the research. A varietyof mathematical models for the sink-effect have been proposed.In some models advanced fluid simulations were used in order totest the influence ofill-defined flow boundary conditions. Theaim of the modelling is to find a formulation with a minimum ofinteraction parameters, which is generally useful, i.e. both insmall-scale laboratory environments and in full-scale like anoffice room. Estimated model parameters are shown to be able toyield a reasonably good fit to experimental data for thesorption process but a less satisfactory fit for the desorptionprocess.</p><p><b>Keywords:</b>sink-effect, sorption, adsorption, diffusion,indoor air quality, volatile organic compounds, VOC,contaminants, building materials</p>

Residential and light-commercial buildings comprise a significant portion of buildings in the United States. They account for a large fraction of the total amount of energy used in the U.S., and they also represent environments where people spend the majority of their time. Thus, the design, construction, and operation of these buildings and their systems greatly affect energy consumption and exposures to airborne pollutants of both indoor and outdoor origin. However, there remains a need to improve knowledge of some key source and removal mechanisms of indoor and outdoor pollutants in residential and light-commercial buildings, as well as their connections to energy use and peak electricity demand. Several standardized field test methods exist for characterizing energy use and indoor air quality in actual buildings, although few explicitly address residential and light-commercial buildings and they are generally limited in scope. Therefore, the work in this dissertation focuses on improving methods to characterize three particular building components for their impacts on exposures to indoor pollutants and their implications for energy consumption: (1) central forced-air heating and cooling (HAC) systems, (2) HAC filters, and (3) building envelopes. Specifically, the research in this dissertation is grouped to fulfill two primary objectives of developing and applying novel methods to: (1) characterize and evaluate central air-conditioning systems and their filters as pollutant removal devices in residential and light-commercial buildings, and to explore their implications for energy consumption, and (2) characterize and evaluate the ability of two particular outdoor pollutants of concern (ozone and particulate matter) to infiltrate indoors through leaks in building envelopes. The research in this dissertation is divided into four primary investigations that fulfill these two objectives. The first investigation (Investigation 1a) addresses Objective 1 by first providing a detailed characterization of a variety of operational characteristics measured in a sample of 17 existing central HAC systems in occupied residential and light-commercial buildings in Austin, Texas, and exploring their implications for exposure to indoor pollutants, energy use, and peak electricity demand. Among the findings in this study, central air-conditioning systems in occupied residential and light-commercial buildings did not operate most of the time, even in the hot and humid climate of Austin, Texas (i.e., ~25% of the time on average in the summer). However, average recirculation rates still make central air-conditioning systems competitive as particle removal mechanisms, given sufficient filtration efficiency. Additionally, this investigation used a larger, much broader, dataset of energy audits performed on nearly 5000 single-family homes in Austin to explore common inefficiencies in the building stock. Residential and light-commercial air-conditioning systems are often inefficient; in fact, residential central air-conditioning systems in particular likely account for nearly 20% of peak electric demand in the City of Austin. As much as 8% of peak demand could be saved by upgrading all single-family homes in Austin to higher-efficiency equipment. The second investigation (Investigation 1b) also addresses Objective 1 by developing and applying a novel test method for measuring the in-situ particle removal efficiency of HAC systems and filters in residential and light-commercial buildings. Results from the novel test method as performed with three test filters and 0.3–10 μm particles in an unoccupied test house agreed reasonably well with results from other field and laboratory test methods. Low-efficiency filters did not increase particle removal much more than simply running the HAC system without a filter, and higher-efficiency filters provided greater than ~50% removal efficiency for most particles greater than 1–2 μm in diameter. The benefit of this test method is that it can be used to measure how filters perform in actual environments, how filter removal efficiency changes with actual dust loading, and how much common HAC design and installation issues, such as low airflow rates, duct leakage, fouled coils, and filter bypass airflow, impact particle removal in real environments. The third investigation (Investigation 2a) addresses Objective 2 by developing and applying a novel test methodology for measuring the penetration of outdoor ozone, a reactive gas, through leaks in exterior building envelopes using a sample of 8 single-family residences in Austin, Texas. These measurements represent the first ever measurements of ozone penetration factors through building envelopes of which I am aware, and penetration factors were lower than the usual assumption of unity (i.e., P = 1) in seven of the eight test homes (ranging from 0.62±0.09 to 1.02±0.15), meaning that some building envelopes provide occupants with more protection from indoor exposures to ozone and ozone reaction byproducts than others. Additionally, ozone penetration factors were correlated with some building characteristics, including the amount of painted wood siding on the exterior envelope and the year of construction, suggesting that simple building details may be used to predict ozone infiltration into homes. Finally, the fourth investigation (Investigation 2b) also addresses Objective 2 by refining and applying a test methodology for measuring the penetration of ambient particulate matter through leaks in building envelopes, and using a sample of 19 single-family residences in Austin, Texas to explore correlations between experimentally-determined particle penetration factors and standardized fan pressurization air leakage tests. Penetration factors of particles 20–1000 nm in diameter ranged from 0.17±0.03 to 0.72±0.08 across 19 homes that relied solely on infiltration for ventilation air. Particle penetration factors were also significantly correlated with results from standardized fan pressurization (i.e., blower door) air leakage tests and the year of construction, suggesting that occupants of older and leakier homes are exposed to more particulate matter of outdoor origin than those in newer tighter homes. Additionally, blower door tests may actually offer some predictive ability of particle penetration factors in single-family homes, which could allow for vast improvements in making easier population exposure estimates. Overall, the work in this dissertation provides new methods and data for assessing the impacts of central air-conditioning systems, filters, and building envelopes on human exposure to indoor pollutants and energy use in residential and light-commercial buildings. Results from these four primary investigations will allow building scientists, modelers, system designers, policymakers, and health scientists to make better informed decisions and assumptions about source and removal mechanisms of indoor pollutants and their impacts on building energy consumption and peak electricity demand. / text