Measurement of CO2 in Outdoor Environments Using LPWAN Based WSN and Its Time Correlation Characteristics

In this paper, we discuss time correlation char-acteristics for measurement results of carbon dioxide (CO
2
) concentration in outdoor environments. The purpose of this paper is to collect an information for the effective placement of sensor nodes in wireless sensor networks (WSNs). We observed CO
2
concentration using WSNs based on low-power wide area networks (LPWANs). To measure CO
2
concentration in outdoor environments, some sensor nodes with CO
2
sensor are deployed in Kamihama campus, Mie University, Japan, and CO
2
concen-tration on the area are measured using LPWAN based WSN. We provide the time correlation characteristics based on the measurement results, and the time correlation characteristics of CO
2
concentration are compared with that of relative humidity.