Journal cover Journal topic
Atmospheric Measurement Techniques An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 3.400 IF 3.400
  • IF 5-year value: 3.841 IF 5-year
  • CiteScore value: 3.71 CiteScore
  • SNIP value: 1.472 SNIP 1.472
  • IPP value: 3.57 IPP 3.57
  • SJR value: 1.770 SJR 1.770
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 70 Scimago H
    index 70
  • h5-index value: 49 h5-index 49
Volume 10, issue 2 | Copyright
Atmos. Meas. Tech., 10, 645-665, 2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 01 Mar 2017

Research article | 01 Mar 2017

A mobile sensor network to map carbon dioxide emissions in urban environments

Joseph K. Lee1, Andreas Christen1, Rick Ketler1, and Zoran Nesic1,2 Joseph K. Lee et al.
  • 1Department of Geography/Atmospheric Science Program, University of British Columbia, Vancouver, BC, Canada
  • 2Biometeorology Group, Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada

Abstract. A method for directly measuring carbon dioxide (CO2) emissions using a mobile sensor network in cities at fine spatial resolution was developed and tested. First, a compact, mobile system was built using an infrared gas analyzer combined with open-source hardware to control, georeference, and log measurements of CO2 mixing ratios on vehicles (car, bicycles). Second, two measurement campaigns, one in summer and one in winter (heating season) were carried out. Five mobile sensors were deployed within a 1 × 12. 7km transect across the city of Vancouver, BC, Canada. The sensors were operated for 3.5h on pre-defined routes to map CO2 mixing ratios at street level, which were then averaged to 100 × 100m grid cells. The averaged CO2 mixing ratios of all grids in the study area were 417.9ppm in summer and 442.5ppm in winter. In both campaigns, mixing ratios were highest in the grid cells of the downtown core and along arterial roads and lowest in parks and well vegetated residential areas. Third, an aerodynamic resistance approach to calculating emissions was used to derive CO2 emissions from the gridded CO2 mixing ratio measurements in conjunction with mixing ratios and fluxes collected from a 28m tall eddy-covariance tower located within the study area. These measured emissions showed a range of −12 to 226CO2ha−1h−1 in summer and of −14 to 163kgCO2ha−1h−1 in winter, with an average of 35.1kgCO2ha−1h−1 (summer) and 25.9kgCO2ha−1h−1 (winter). Fourth, an independent emissions inventory was developed for the study area using buildings energy simulations from a previous study and routinely available traffic counts. The emissions inventory for the same area averaged to 22.06kgCO2ha−1h−1 (summer) and 28.76kgCO2ha−1h−1 (winter) and was used to compare against the measured emissions from the mobile sensor network. The comparison on a grid-by-grid basis showed linearity between CO2 mixing ratios and the emissions inventory (R2 = 0. 53 in summer and R2 = 0. 47 in winter). Also, 87% (summer) and 94% (winter) of measured grid cells show a difference within ±1 order of magnitude, and 49% (summer) and 69% (winter) show an error of less than a factor 2. Although associated with considerable errors at the individual grid cell level, the study demonstrates a promising method of using a network of mobile sensors and an aerodynamic resistance approach to rapidly map greenhouse gases at high spatial resolution across cities. The method could be improved by longer measurements and a refined calculation of the aerodynamic resistance.

Publications Copernicus
Short summary
We developed a method for directly measuring emissions of the greenhouse gas carbon dioxide in cities, using a mobile sensor network operated on vehicles (car, bikes) with open-source components. In two measurement campaigns, the network was tested in the City of Vancouver, BC, Canada. Carbon dioxide concentrations and emissions were mapped at block level (100 × 100 m). Our measured emissions agreed generally with a fine-scale independent emissions inventory.
We developed a method for directly measuring emissions of the greenhouse gas carbon dioxide in...