Plant and Environmental Sciences, Department of Environmental Health Science, University of Shizuoka, Shizuoka Japan.
Sensors (Basel). 2012;12(3):3641-55. doi: 10.3390/s120303641. Epub 2012 Mar 16.
Many sensors have to be used simultaneously for multipoint carbon dioxide (CO(2)) observation. All the sensors should be calibrated in advance, but this is a time-consuming process. To seek a simplified calibration method, we used four commercial CO(2) sensor models and characterized their output tendencies against ambient temperature and length of use, in addition to offset characteristics. We used four samples of standard gas with different CO(2) concentrations (0, 407, 1,110, and 1,810 ppm). The outputs of K30 and AN100 models showed linear relationships with temperature and length of use. Calibration coefficients for sensor models were determined using the data from three individual sensors of the same model to minimize the relative RMS error. When the correction was applied to the sensors, the accuracy of measurements improved significantly in the case of the K30 and AN100 units. In particular, in the case of K30 the relative RMS error decreased from 24% to 4%. Hence, we have chosen K30 for developing a portable CO(2) measurement device (10 × 10 × 15 cm, 900 g). Data of CO(2) concentration, measurement time and location, temperature, humidity, and atmospheric pressure can be recorded onto a Secure Digital (SD) memory card. The CO(2) concentration in a high-school lecture room was monitored with this device. The CO(2) data, when corrected for simultaneously measured temperature, water vapor partial pressure, and atmospheric pressure, showed a good agreement with the data measured by a highly accurate CO(2) analyzer, LI-6262. This indicates that acceptable accuracy can be realized using the calibration method developed in this study.
许多传感器需要同时用于多点二氧化碳（CO2）观测。所有传感器都应提前进行校准，但这是一个耗时的过程。为了寻求简化的校准方法，我们使用了四种商业 CO2 传感器模型，并对其在环境温度和使用时间长度以及偏移特性方面的输出趋势进行了特征描述。我们使用了四个不同 CO2 浓度（0、407、1110 和 1810 ppm）的标准气体样本。K30 和 AN100 模型的输出与温度和使用时间长度呈线性关系。使用相同型号的三个单独传感器的数据来确定传感器模型的校准系数，以最小化相对 RMS 误差。当对传感器进行校正时，K30 和 AN100 单元的测量精度显著提高。特别是在 K30 的情况下，相对 RMS 误差从 24%降低到 4%。因此，我们选择 K30 来开发一种便携式 CO2 测量设备（10×10×15 cm，900 g）。CO2 浓度、测量时间和位置、温度、湿度和大气压的数据可以记录到安全数字（SD）存储卡上。该设备监测了一所高中教室的 CO2 浓度。通过同时测量温度、水蒸气分压和大气压对 CO2 浓度进行校正后，与高精度 CO2 分析仪 LI-6262 测量的数据吻合较好。这表明，使用本研究中开发的校准方法可以实现可接受的精度。
