An Integrated Modelling Approach to Estimate Urban Traffic Emissions by Aarshabh Misra A thesis submitted in conformity with the requirements for the degree of Master of Applied Sciences Department of Civil Engineering University of Toronto © Copyright by Aarshabh Misra, 2012 An Integrated Modelling Approach to Estimate Urban Traffic Emissions Aarshabh Misra Master of Applied Sciences Department of Civil Engineering University of Toronto 2012 Abstract Vehicular emissions contribute significantly to poor air quality in urban areas. An integrated modelling approach is adopted to estimate microscale urban traffic emissions. The modelling framework consists of a traffic microsimulation model, a microscopic emissions model, and two dispersion models. This framework is applied to a traffic network in downtown Toronto to evaluate summer time morning peak traffic emissions during weekdays for carbon monoxide and nitrogen oxide. The model predicted results are validated against sensor observations with a reasonably good fit. Availability of local estimates of ambient concentration is useful for accurate comparisons of total predicted concentrations with observed concentrations. Both predicted and observed concentrations are significantly smaller than the National Ambient Air Quality Objectives established by Environment Canada. Sensitivity analysis is performed on a set of input parameters and horizontal wind speed is found to be the most influential factor in pollutant dispersion. ii Acknowledgments I find it ironical how acknowledgements are featured at the very beginning of a thesis even though they are the last thing written out once all the ‘real’ writing is complete. Nonetheless, I feel this is probably the most well read section of any thesis! I wish to express my sincere gratitude to thesis supervisors Professor Matthew Roorda and Professor Heather MacLean for the steady support, guidance, and useful feedback they gave me at critical junctures, during the course of my thesis. The innumerable meetings, discussions, and e-mail exchanges were really helpful in channelling my energy in the right direction. I would like to thank Professor Greg Evans and staff at the SOCAAR laboratory for providing generous advice, along with abundant pollutant concentration and traffic data at the St. George and College Street intersection. I would like to recognise the work of Greg Hoy in developing the St. George and College Street network in PARAMICS, and organising the manual traffic count survey, both of which were used in this research; also, I am thankful to everyone who participated in the manual traffic count last year. I am grateful to Michael Brown, from the Los Alamos National Laboratory, who provided quick answers to my questions on the QUIC modelling system. My parents and my brother have shown immense confidence in my abilities for several years now, and it has kept me steady through thick and thin. I am deeply indebted to them for their unfaltering support. I would also like to acknowledge the contribution of my office mates, Rinaldo (who helped me with statistics), Keith (with whom I formed a semi-functional acoustic guitar cover band), and Mohamed (who played table tennis with me in times of boredom and un-productivity). Lastly, everyone in the Transportation Research Group at the ITS lab helped me on numerous occasions throughout my stint here; I will definitely miss that collective brain power I could just tap into every day at work for the last two years. Aarshabh Misra, May 5 th , 2012 iii Table of Contents Acknowledgments .......................................................................................................................... iii Table of Contents ........................................................................................................................... iv List of Tables ................................................................................................................................ vii List of Figures .............................................................................................................................. viii Chapter 1 ......................................................................................................................................... 1 1 Introduction ................................................................................................................................ 1 1.1 Background and Motivation ............................................................................................... 1 1.2 Purpose and Scope .............................................................................................................. 4 1.3 Significance and Potential ................................................................................................... 5 1.4 Structure of Thesis .............................................................................................................. 6 Chapter 2 ......................................................................................................................................... 8 2 Overview of Methodology ......................................................................................................... 8 2.1 Air Quality Modelling Framework ..................................................................................... 8 2.2 Study Area Specification .................................................................................................. 10 2.3 Concentration Terms ......................................................................................................... 11 Chapter 3 ....................................................................................................................................... 15 3 Traffic Microsimulation Modelling: Method ........................................................................... 15 3.1 Introduction to Traffic Microsimulation ........................................................................... 15 3.2 Traffic Modelling Review ................................................................................................. 15 3.3 Model Selection ................................................................................................................ 16 3.4 Network Development and Inputs .................................................................................... 17 3.4.1 Traffic Data Collection ......................................................................................... 18 3.4.2 Origin-Destination (O-D) Matrix .......................................................................... 19 3.4.3 Other Inputs .......................................................................................................... 23 iv Chapter 4 ....................................................................................................................................... 25 4 Emissions Modelling: Method ................................................................................................. 25 4.1 Emission Modelling Review ............................................................................................. 25 4.2 Model Selection ................................................................................................................ 26 4.2.1 Comprehensive Modal Emissions Model (CMEM) ............................................. 27 4.3 Vehicle Type Distribution ................................................................................................. 27 4.4 Emission Output Processing ............................................................................................. 28 Chapter 5 ....................................................................................................................................... 30 5 Pollutant Dispersion Modelling: Method ................................................................................. 30 5.1 Dispersion Modelling and Meteorology ........................................................................... 30 5.1.1 Dispersion Modelling Review and Model Selection ............................................ 33 5.2 AERMOD ......................................................................................................................... 36 5.3 Quick Urban and Industrial Complex (QUIC) .................................................................. 38 5.4 Dispersion Modelling Inputs: Data Processing ................................................................. 40 5.4.1 AERMOD Inputs .................................................................................................. 40 5.4.2 QUIC Inputs .......................................................................................................... 44 5.5 Sensitivity of Traffic Microsimulation Random Seed ...................................................... 46 Chapter 6 ....................................................................................................................................... 48 6 Model Results and Analysis ..................................................................................................... 48 6.1 Pollutant Dispersion Analysis ........................................................................................... 48 6.1.1 Observed Pollutant Data ....................................................................................... 48 6.1.2 AERMOD Results ................................................................................................ 51 6.1.3