Copyright by Éléna Laure Nirlo 2014 The Dissertation Committee for Elena Laure Nirlo Certifies that this is the approved version of the following dissertation: Assessing and Controlling Concentrations of Volatile Organic Compounds in the Retail Environment Committee: Richard L. Corsi, Supervisor Jeffrey A. Siegel, Co-Supervisor Atila Novoselac Kerry A. Kinney Michael Webber Assessing and Controlling Concentrations of Volatile Organic Compounds in the Retail Environment by Éléna Laure Nirlo, M.S.E Dissertation Presented to the Faculty of the Graduate School of The University of Texas at Austin in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy The University of Texas at Austin May 2014 Dedication To my mother, father, and sister, for keeping me grounded and yet pushing me to live to the fullest. Acknowledgements I would like to thank my advisors - Dr. Jeffrey Siegel for trusting me to be a part of his team in the first place and for his sound advice ever since; and Dr. Richard Corsi for taking me in midway through and always offering me his best. I would also like to thank Dr. Neil Crain who has played a major part in my growth, scientific, academic, and otherwise over the past four years, with his daily presence and guidance. I would like to thank Dori Eubank for her soothing words as she managed to fix every crisis in my academic life. I would also like to acknowledge the support staff at the Center for Energy and Environmental Resources, particularly Susan McCoy and Steve Orwick, for their dedication. Special thanks to Clément Cros, friend and parrain, for first inspiring me to join the program, and for his precious advice to this day. Thanks to the students of the Air Research Group: Erin Darling, Priscilla Guerrero, Matt Earnest, Brent Stephens, Jorge Urquidi, Jennifer Wang - my favorite writing buddy, and many others. I would like to extend special thanks to Marwa Zaatari with whom I shared the major and best part of this adventure - I really was lucky that you came into this project and into my life. I would like to acknowledge my funding sources: the William Robertson Welty Scholarship, the Agnes T. and Charles F. Wiebusch Fellowship, and ASHRAE through the RP1596 project and through a Graduate Student Grant-in-Aid. I would like to thank my family – Papa, Maman, Anabelle, Pépé, Mémé, Mamie, and Papi whom I miss - who may have no idea what this dissertation is about, but still pushed me through it all along. I would like to thank my dear friends here - Anne, Aurore, Natalia, Fernando, Catherine, Cedric, Arielle, Claire, Mathieu, Philippe, Gwen - and there - Virginie, Isabelle, Laure, Nathalie - for supporting me and making sure I enjoyed life as a graduate student. And finally, thanks to Michael Harmon for carrying me through the past two years of this adventure - I could not have done it without you. v Assessing and controlling concentrations of volatile organic compounds in the retail environment Éléna Laure Nirlo, Ph.D. The University of Texas at Austin, 2014 Supervisors: Richard L. Corsi, Jeffrey A. Siegel Retail buildings have potential for both short-term (customer) and long-term (occupational) exposure to indoor pollutants. A multitude of sources of volatile organic compounds (VOCs) are common to the retail environment. Volatile organic compounds can be odorous, irritating or carcinogenic. Through a field investigation and modeling study, this dissertation investigates exposure to, and control of, VOCs in retail buildings. Fourteen U.S. retail stores were tested one to four times each over a period of a year, for a total of twenty-four test visits. Over a hundred parameters were investigated to characterize each of the buildings, including ventilation system parameters, and airborne pollutants both indoors and outdoors. Concentrations of VOCs were simultaneously measured using five different methods: Summa canisters, sorbent tubes, 2,4- dinitrophenylhydrazine (DNPH) tubes, a photoionization detector (PID), and a colorimetric real-time formaldehyde monitor (FMM). The resulting dataset was analyzed to evaluate underlying trends in the concentrations and speciation of VOCs, identify influencing factors, and determine contaminants of concern. A parametric framework based on a time-averaged mass balance was then developed to compare strategies to reduce formaldehyde concentrations in retail stores. Mitigation of exposure to vi formaldehyde through air cleaning (filtration), emission control (humidity control), and targeted dilution (local ventilation) were assessed. Results of the field study suggested that formaldehyde was the most important contaminant of concern in the retail stores investigated, as all 14 stores exceeded the most conservative health guideline for formaldehyde (OEHHA TWA REL = 7.3 ppb) during at least one sampling event. Formaldehyde monitors were strongly correlated with DNPH tube results. The FMM showed promising characteristics, supporting further consideration as real-time indicators to control ventilation and/or environmental parameters. The vast majority of the remaining VOCs were present at low concentrations, but episodic activities such as cooking and cleaning led to relatively high indoor concentrations for ethanol, acetaldehyde, and terpenoids. Results of the modeling effort demonstrated that local ventilation caused the most uniform improvements to indoor formaldehyde concentrations across building characteristics, but humidity control appeared to have a very limited impact. Filtration used under specific conditions could lead to larger decreases in formaldehyde concentrations than all other strategies investigated, and was the least energy-intensive. vii Table of Contents List of Tables ......................................................................................................... xi List of Figures ...................................................................................................... xiv 1. Introduction ..........................................................................................................1 1.1. Problem statement ....................................................................................1 1.2. Objectives ................................................................................................2 1.3. Scope and Integration ..............................................................................3 1.4. Organization .............................................................................................5 2. Background ..........................................................................................................6 2.1. Volatile organic compounds in retail stores .............................................6 2.2. Sampling techniques ................................................................................7 2.2.1. The challenges of measuring VOCs ............................................8 2.2.2. Presentation of selected techniques .............................................9 2.2.3. Comparison of methods .............................................................10 2.3. Formaldehyde control strategies ............................................................11 2.3.1. Formaldehyde removal ..............................................................11 2.3.2. Formaldehyde control using relative humidity ..........................12 2.3.3. Modeling formaldehyde removal strategies ...............................13 3. Methods..............................................................................................................14 3.1. Experimental methods ...........................................................................14 3.1.1. Description of the sample ..........................................................14 3.1.2. VOC measurements ...................................................................15 3.1.3. Other selected measurements .....................................................16 3.2. Data analysis ..........................................................................................17 3.2.1. Time-integrated measurements ..................................................17 3.2.2. Time-resolved measurements ....................................................17 3.3. Modeling ................................................................................................18 3.3.1. Indoor formaldehyde concentrations .........................................18 viii 3.3.2. Energy implications ...................................................................21 3.3.3. Framework .................................................................................22 3.3.4. Case study ..................................................................................23 4. Results and discussion .......................................................................................25 4.1. Field characterization of volatile organic compounds in fourteen retail stores ....................................................................................................25 4.1.1. Indoor concentrations and potential indoor sources ..................25 4.1.2. Contribution of outdoor sources ................................................27 4.1.3. Temporal profiles of total volatile organic compound ..............28 4.1.4. Comparison with other indoor environments ............................30 4.2. Determination of contaminants of concern ............................................30 4.2.1. Time-integrated measurements of VOCs ...................................31