Ultrafine Particles and Freeways

Transcription

1 UNIVERSITY OF CALIFORNIA Los Angeles Ultrafine Particles and Freeways A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Environmental Health Sciences by Yifang Zhu 2003

2 This dissertation of Yifang Zhu is approved. B J (7)'("'('d ~lj Ie 2~/qs dw6 Steve Colome Sheldon K. Friedlander Arthur M. Winer William C. Hinds, Committee Chair University of California, Los Angeles 2003 ii

3 TABLE OF CONTENTS Dedication Table of Contents List of Figures List of Tables Acknowledgements VITA Abstract Page IV IX xiii XIV xvi xviii Chapter 1 Introduction 1.1 Ambient Particulate Matter Physical Properties of ambient PM Chemical Properties of ambient PM Ultrafine Particles 1.2 Health Effect of Ultrafine Particles Toxicological Studies Epidemiology Studies 1.3 Vehicle Emitted Ultrafine Particles Dynamometer Studies Diesel-powered Vehicles Gasoline Vehicles Real-world Studies 1.4 Thesis Overview Statement of the Problem IV

4 References Objectives Thesis layout Chapter 2 Ultrafine Particles near the 405 freeway in summer 26 (Reference: Yifang Zhu, William C. Hinds, Seongheon Kim and Constantinos Sioutas "Concentration and SIze distribution of ultrafine particles near a major highway", 2002, J. of Air and Waste Management Association, 52: ) Abstract Introduction Methods Description of Sampling Site Sampling and Instrumentation Results and Discussion Wind Effects Traffic Effects Change in U1trafine Particle Size Distribution with Increasing Distance 31 Carbon Monoxide, Black Carbon, Particle Mass and Number 35 Conclusions 35 Acknowledgements 35 References 35 v

5 Chapter 3 Ultrafine Particles near the 710freeway in summer 37 (Reference: Yifang Zhu, William C. Hinds, Si Shen, Seongheon Kim and Constantinos Sioutas "Study of Ultrafine Particles near a Major Highway with Heavy-duty Diesel Traffic", 2002, Atmospheric Environment, 36: ) Abstract Introduction Experimental Description of Sampling Site Sampling and Instrumentation Results and Discussion Wind Effects Traffic Effects Change in Ultrafine Particle Size Distribution with Increasing Distance 42 Carbon Monoxide, Black Carbon, Particle Mass and Number 46 Conclusions 47 Acknowledgements 47 References 47 VI

6 Chapter 4 Ultrafine Particles near the 405 and 710 freeways in winter 50 (Reference: Yifang Zhu, William C. Hinds, Si Shen and Constantinos Sioutas "Seasonal Trends of Concentration and Size Distribution of Ultrafine Particles near Major Highways in Los Angeles", Accepted by Aerosol Science and Technology, 2003.) Abstract Introduction Experimental Description of Sampling Site Sampling and Instrumentation 57 Results and Discussion Conclusions References Chapter 5 Predicting Ultrafine Particles near freeways 78 (Reference: Yifang Zhu, William C. Hinds and Constantinos Sioutas "Predicting ultrafine particles near freeways", to be submitted, 2003.) Abstract Introduction Models Atmospheric Coagulation Condensation Dispersion and Evaporation VB

7 Adsorption 91 Results and Discussion 92 Conclusion 111 References 112 Chapter 6 Summary and the Opportunity for Future Research 117 V111

8 LIST OF TABLES Chapter 2 Table 1. Sampling dates and instruments used. 29 Table 2. Measured average concentrations at increasing distances from the freeway. 34 Chapter 3 Table 1. Sampling dates, time nd instruments used. 40 Table 2. Measured average concentrations at increasing distances from the freeway. 46 Chapter 4 Table 4.1. Sampling dates, time, sites and instruments used. 57 Table 4.2 Comparison of sampling conditions in summer and winter. 60 Chapter 5 Table 5.1. Ultrafine particle number concentrations III different SIze ranges at different sampling locations near the 405 freeway. 100 Table 5.2 Sensitivity analysis of ultrafine particle number concentrations in different size ranges at different sampling locations near the 405 freeway due to incomplete mixing 101 Table 5.3. PAR properties related to the condensation/evaporation model. 104 Table 5.4. PAH properties related to the adsorption model. 105 Table 5.5. Particle number concentration emission factors. 110 XIll

9 ACKNOWLEDGEMENTS I sincerely acknowledge the following people who have contributed to my doctoral research. First, I would like to express my deepest appreciation to my advisor and mentor, Dr. Hinds. Without him, my graduate study could not have been such a most valuable and enjoyable learning experiences. Not only did he give me guidance on projects and freedom to explore new frontiers, but he also cares about my professional growth. I would also like to acknowledge my co-authors on three published papers that were used in this dissertation: Dr. Costas Sioutas, Dr. Seongheon Kim and Si Shen. Special thanks are due to Mr. William L. Livingston and his staff at Los Angeles National Cemetery for their cooperation. I would also like to thank Mr. Hyuntae Kim, Ms. Sara Firl for their assistance with the field measurements. I also want to express my deepest love and appreciation to my parents. Their continuous support throughout the years of my education is what I will always remember. I also want to thank my dearest husband, Yuqing Zhang, for his unconditional support through my graduate studies. In addition, I would like to acknowledge the Air and Waste Management Association. for chapter 2 (Journal of Air and Waste Management Association, 52: ) reprint permission and Elsevier for chapter 3 (Atmospheric Environment, 36: ) reprint permission. XIV

10 This work was supported by the Southern California Particle Center and Supersite: U.S. Environmental Protection Agency grant number R , California Air Resources Board contract number , and the Southern California Environmental Health Center, National Institute of Environmental Health Sciences (NIEHS) Grant # 5 P30 ES xv

11 VITA March 31,1974 Born, Beijing, China 1997 B. Eng. Environmental Engineering Tsinghua University, China 1999 M.S. in Environmental Science and Engineering, Kwangju Institute of Science and Technology, Korea Staff Research Associate, Institute of Environmental Health University of California, Los Angeles 1999,2002 Chancellor's Fellowship University of California, Los Angeles 2002 Samuel J. Tibbitts Fellowship University of California, Los Angeles PUBLICATIONS AND PRESENTATIONS William C. Hinds, Nola J. Kennedy, and Yifang Zhu, "An eight-channel, five-stage personal cascade impactor" American Association for Aerosol Research annual conference, Peter A. Jaques, Bill Grant, Yifang Zhu, Jeffrey L. Ambs, Constantinos Sioutas, and Philip M. Fine "Field Evaluation Of The Differential Teom Monitor By Comparison With Semi-continuous And Integrated Ambient Particulate Mass And Nitrate In Claremont, California" American Association for Aerosol Research annual conference, Hyuntae Kim, Yifang Zhu, William C. Hinds and Ken W. Lee, "Experimental study of small cyclones as particle concentrators" 2002, J Aerosol Science 33, Seongheon Kim, Si Shen, Yifang Zhu, William Hinds and Constantinos Sioutas "Size Distribution, Diurnal and Seasonal Trends of Ultra fine Particles in Source and Receptor Sites of the Los Angeles Basin", 2002, J of Air and Waste Management Association, 52: Si Shen, Peter A. Jaques, Yifang Zhu, Michael D. Geller, and Constantinos Sioutas "Evaluation of the SMPS -APS as a continuous monitor for measuring PM 25, PM lo XVI

12 and course (PM25-lo) concentrations", 2002, Atmospheric Environment, 36: Yifang Zhu, and Ken W. Lee, "Experimental study on small cyclones operating at high flowrates" 1999, J Aerosol Science, 30, Yifang Zhu, M.C Kim, Ken W. Lee, O.P Chong, M. Kuhlman, " Design and evaluation of a novel double cyclone" 2001, Aerosol Science and Technology, 34, Yifang Zhu, William C. Hinds, Seongheon Kim and Constantinos Sioutas "Concentration and size distribution of ultra fine particles near a major highway", 2002, J of Air and Waste Management Association, 52: Yifang Zhu, William C. Hinds, Si Shen, Seongheon Kim and Constantinos Sioutas "Study of Ultra fine Particles near a Major Highway with Heavy-duty Diesel Traffic", 2002, Atmospheric Environment, 36: Yifang Zhu, William C. Hinds, Si Shen and Constantinos Sioutas "Seasonal Trends of Concentration and Size Distribution of Ultra fine Particles near Major Highways in Los Angeles", Accepted by Aerosol Science and Technology, Yifang Zhu and William C. Hinds "Predicting Ultrafine Particles near Major Highways", Submitted to Environmental Science and Technology. Yifang Zhu, William C. Hinds, H. T. Kim and K. W. Lee, "Numerical modeling of the performance of small virtual cyclones" American Association for Aerosol Research annual conference, Yifang Zhu, William C. Hinds and Constantinos Sioutas, "Ultrafine particles near major highways in Los Angeles" Particulate Matter: Atmospheric Sciences, exposure and the fourth colloquium on PM and human health, Pittsburgh, March xvii

13 ABSTRACT OF THE DISSERTATION Ultrafine Particles and Freeways by Yifang Zhu Doctor of Philosophy in Environmental Health Sciences University of California, Los Angeles, 2003 Professor William C. Hinds, Chair Ultrafine particles (diameter < 100 nm) have been suggested as a possible causative agent for the observed increases in mortality and morbidity with increases in particulate matter (PM) concentrations. Systematic measurements of the concentration and size distribution of ultra fine particles were conducted in the vicinity ofinterstate 405 (mostly gasoline traffic) and Interstate 710 (heavy-duty diesel traffic) in Los Angeles during the summer, 2001 and the winter Measurements were taken at xviii

14 increasing distances downwind from each of the freeway. At each sampling location, concentrations of carbon monoxide (CO) and black carbon (BC) were also measured. For the conditions of these measurements, relative concentration of CO, black carbon and particle number track each other well as one moves away from the freeway. Particle number concentration (6-220 nm) decreased exponentially with downwind distance from the freeway. The maximum number concentration that was observed near the freeway was about 25 time greater than that for the background location. It suggests that people, who live, work, or travel within 100 m downwind of major traffic sources, will have much higher ultrafine particle exposure than those who live farther away from such sources. The decay rates of CO and BC are slightly greater in summer than in winter for both freeways suggesting a weaker atmospheric dilution effect in winter. These data may be useful for epidemiological studies to estimate exposure to ultrafine particles in the vicinity of major highways and to evaluate their adverse health effects. A mathematical model was developed to simulate ultrafine particle number concentrations and size distribution near freeways. The model predicts particle number concentration near freeways with more than 90% accuracy. There are significant discrepancies between the model predicted and measured ultrafine particle size distributions. Atmospheric dispersion was found to be the dominant mechanisms in determing the particle number concentration near freeways. xix ---~ ~