title: The effect of ego-motion on environmental monitoring.
abstract: Air pollution has a proven impact on public health. Currently, pollutant levels are obtained by high-priced, sizeable, stationary Air Quality Monitoring (AQM) stations. Recent developments in sensory and communication technologies have made relatively low-cost, micro-sensing units (MSUs) feasible. Their lower power consumption and small size enable mobile sensing, deploying single or multiple units simultaneously. Recent studies have reported on measurements acquired by mobile MSUs, mounted on cars, bicycles and pedestrians. While these modes of transportation inherently present different velocity and acceleration regimes, the effect of the sensors' varying movement characteristics have not been previously accounted for. This research assesses the impact of sensor's motion on its functionality through laboratory measurements and a field campaign. The laboratory setup consists of a wind tunnel to assess the effect of air flow on the measurements of nitrogen dioxide and ozone at different velocities in a controlled environment, while the field campaign is based on three cars mounted with MSUs, measuring pollutants and environmental variables at different traveling speeds. In both experimental designs we can regard the MSUs as a moving object in the environment, i.e. having a distinct ego-motion. The results show that MSU's behavior is highly affected by variation in speed and sensor placement with respect to direction of movement, mainly due to the physical properties of installed sensors. This strongly suggests that any future design of MSU must account for the speed effect from the design stage all the way through deployment and results analysis. This is the first report examining the influence of airflow variations on MSU's ability to accurately measure pollutant levels.
authors.affiliation: Technion Enviromatics Lab. (TechEL), Dept. of Environmental, Water and Agricultural Engineering, Faculty of Civil & Environmental Engineering, The Technion - Israel Institute of Technology, Israel; Technion Center of Excellence in Exposure Science and Environmental Health (TCEEH), Dept. of Environmental, Water and Agricultural Engineering, Faculty of Civil & Environmental Engineering, The Technion - Israel Institute of Technology, Israel.
authors.forename: Uri
authors.initials: U
authors.lastname: Lerner
authors.affiliation: Technion Enviromatics Lab. (TechEL), Dept. of Environmental, Water and Agricultural Engineering, Faculty of Civil & Environmental Engineering, The Technion - Israel Institute of Technology, Israel; Technion Center of Excellence in Exposure Science and Environmental Health (TCEEH), Dept. of Environmental, Water and Agricultural Engineering, Faculty of Civil & Environmental Engineering, The Technion - Israel Institute of Technology, Israel.
authors.forename: Tamar
authors.initials: T
authors.lastname: Yacobi
authors.affiliation: Technion Center of Excellence in Exposure Science and Environmental Health (TCEEH), Dept. of Environmental, Water and Agricultural Engineering, Faculty of Civil & Environmental Engineering, The Technion - Israel Institute of Technology, Israel.
authors.forename: Ilan
authors.initials: I
authors.lastname: Levy
authors.affiliation: Technion Enviromatics Lab. (TechEL), Dept. of Environmental, Water and Agricultural Engineering, Faculty of Civil & Environmental Engineering, The Technion - Israel Institute of Technology, Israel; Technion Center of Excellence in Exposure Science and Environmental Health (TCEEH), Dept. of Environmental, Water and Agricultural Engineering, Faculty of Civil & Environmental Engineering, The Technion - Israel Institute of Technology, Israel.
authors.forename: Sharon A
authors.initials: SA
authors.lastname: Moltchanov
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain; Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain.
authors.forename: Tom
authors.initials: T
authors.lastname: Cole-Hunter
authors.affiliation: Technion Enviromatics Lab. (TechEL), Dept. of Environmental, Water and Agricultural Engineering, Faculty of Civil & Environmental Engineering, The Technion - Israel Institute of Technology, Israel; Technion Center of Excellence in Exposure Science and Environmental Health (TCEEH), Dept. of Environmental, Water and Agricultural Engineering, Faculty of Civil & Environmental Engineering, The Technion - Israel Institute of Technology, Israel. Electronic address: fishbain@technion.ac.il.
authors.forename: Barak
authors.initials: B
authors.lastname: Fishbain
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution; D004784:Environmental Monitoring / Q000379:methods*; D009585:Nitrogen Dioxide / Q000032:analysis; D010126:Ozone / Q000032:analysis; D012107:Research Design
chemical_list: D000393:Air Pollutants; D010126:Ozone; D009585:Nitrogen Dioxide
keywords: Air pollution; Ego-motion; Exposure; Micro sensing units; Micro-Sensor Calibration; Monitoring