REAL-TIME AIR QUALITY MEASUREMENTS USING MOBILE PLATFORMS BY PARVEEN SEVUSU A thesis submitted to the Graduate School—New Brunswick Rutgers, the State University of New Jersey In partial fulfillment of the requirements For the degree of Master of Science Graduate Program in Computer Science Written under the direction of Liviu Iftode And approved by New Brunswick, New Jersey Jan, 2015 ABSTRACT OF THE THESIS Real-time Air Quality Measurements Using Mobile Platforms By PARVEEN SEVUSU Thesis Director: Liviu Iftode Air pollution poses a serious threat to our health and quality of life. Measuring pollution in the air we breathe and sharing the results with our peers is an important step in increasing social awareness for creating a clean environment. Usually, pollution measurements are conducted using expensive monitors at fixed locations. These measurements fail to provide accurate real-time pollution information in most of the highly polluted roads. It is desirable to have access to real time fine-grained measurements to be able to quickly analyze and identify alarming levels of pollutants. Pervasiveness of smart phones with internet connectivity and increased availability of personal air quality sensors provide a unique opportunity to develop air pollution conscious community of users for collecting and sharing real time air pollution data. In this thesis, we propose air quality monitoring through mobile sensors, which are low-power, low-cost, designed to sample air pollutants such as carbon mono-oxide, nitrogen oxide, sulphur dioxide, environmental temperature, humidity and air pressure and communicate via Bluetooth with a smartphone. We built an iOS mobile application that makes use of location services available on the mobile phones, to record GPS co-ordinates along with air pollution readings. We built a mobile to cloud replication model, data exchange protocol and outlier detection for anomalous sensor readings. We also employed spatial database queries to optimize location based pollution data sharing and visualization of pollution data overlays on mobile map displays. We evaluated our mobile pollution-sensing model against stationary NJ DEP monitor and studied spatial granularity of ii pollution data. iii Acknowledgements Firstly, I would like to sincerely thank my advisors, Professor Liviu Iftode and Professor Badri Nath, for the patient guidance, encouragement and advice they provided me throughout the course of this research. I am deeply indebted to them for introducing me to the field of mobile sensors research and giving me the unique opportunity to build a valuable model as part of this thesis. Their insightful comments and constructive criticisms at different stages of my research were thought provoking and helped me focus my ideas. Secondly, my sincere thanks to Professor Ann Marie Carlton, who provided guidance with respect to sensor calibration and accuracy determination. Many thanks to her for getting us access to EPA labs and all her guidance on method detection techniques. A huge thank you to Avraham Teitz for providing us access to the EPA lab and equipment; and for assisting with the calibration techniques. I would also like to thank my committee member, Professor Vinod Ganapathy, for serving on my committee and for instilling a strong interest in the field of information security by means of his Security Seminar. My many thanks to Srinivas Devarakonda, who as a mentor and colleague on this project, helped me with suggestions and ideas during roadblocks, and for providing moral support all through this project. I would also like to thank him for giving me an insight into his model for pollution gathering on public transportation vehicles, which laid the foundation for my study. I am also very grateful to Mansi Parikh, who was a tremendous help in calibration of the sensors. Many thanks to her for the interesting discussions on data analysis. I would like to thank Hongzhang Liu, Ruilin Liu, Eduard and Daehan who helped me with various aspects of the research such as data collection and their assistance in setting up the cloud server. Many thanks to them for all the interesting discussions we had, which were very enriching. iv Finally, I would like to extend my gratitude and thanks to my family, who has been supportive throughout my years of study. I am truly grateful for their love and support. I thank them for making my student life easier and enjoyable. v Dedication To my parents vi Table of Contents Table of Contents ABSTRACT OF THE THESIS ........................................................................................... ii Acknowledgements ................................................................................................... iv Dedication ................................................................................................................. vi Table of Contents ..................................................................................................... vii List of Figures ............................................................................................................ ix Chapter 1 ................................................................................................................... 1 Introduction ............................................................................................................... 1 1.1 Current State of Air quality monitoring ............................................................................................ 2 1.2 Need for Real-time Air Quality Information .................................................................................... 6 1.3 Online Social Communities for Real-time Air Quality Monitoring ......................................... 8 1.4 Challenges in Building a Mobile Air Pollution Sensing Social Community ....................... 10 1.5 Thesis ............................................................................................................................................................. 11 1.6 Related Work .............................................................................................................................................. 12 1.7 Summary of Thesis Contributions ..................................................................................................... 14 1.8 Contributors to the Dissertation: ....................................................................................................... 15 Chapter 2 ................................................................................................................. 16 Mobile Air Pollution Sensing Community .................................................................. 16 2.1 Design Goals ................................................................................................................................................ 16 2.2 Design Overview ....................................................................................................................................... 17 2.3 Mobile Application Design .................................................................................................................... 21 2.4 Social Community Design ...................................................................................................................... 23 2.5 Cloud Services Design ............................................................................................................................. 25 2.6 Pollution Sensing Inside Motor Vehicles ........................................................................................ 26 2.7 Spatial Query Design ............................................................................................................................... 28 Chapter 3 ................................................................................................................. 32 Implementation ....................................................................................................... 32 3.1 Hardware ..................................................................................................................................................... 32 3.2 weBreathe iPhone Application ........................................................................................................... 32 3.3 weBreathe Web Services ....................................................................................................................... 34 Chapter 4 ................................................................................................................. 37 Optimization ............................................................................................................ 37 4.1 Goals ............................................................................................................................................................... 37 4.2 Data Transfer Optimization .................................................................................................................. 38 4.3 Data Transfer Cost Optimization ........................................................................................................ 40 vii 4.4 Pollution Map Display Optimization ................................................................................................. 41 4.5 Outlier Detection ....................................................................................................................................... 42 4.6 Speed Based Sensor Reading ..............................................................................................................