基于电化学传感器的大气NO2与O3监测研究

利用四电极电化学传感器开展大气NO₂和O₃监测研究.为解决温度和湿度对传感器响应的影响问题，提出了一种具有温湿度补偿与零点校正功能的大气NO₂和O₃测量结果校准模型，通过活性炭吸附特性获得干净的背景气体，实现传感器准确的零点校正，并利用实验系统实测数据结合多元线性回归方法获得校准模型参数.首先对传感器线性响应特性进行了测试，发现O₂和O₃的测量灵敏度分别为3.889 ppbv·mV^-1和4.107 ppbv·mV^-1.同时，在合肥西郊科学岛开展了为期2 d的大气NO₂和O₃连续观测，发现两者的浓度分别为0~30 ppbv和2~100 ppbv.最后将传感器观测结果与NO_x/O₃分析仪测量结果进行了回归分析，发现两者测得的NO₂线性拟合斜率为0.9701±0.0182，R²为0.8378，测得的O₃线性拟合斜率为0.9850±0.0101，R²为0.9431.研究表明，校准后的电化学传感器可用于大气NO₂和O₃的长期监测，可为推动大气环境监测技术发展提供新的思路.

Monitoring of atmospheric NO2 and O3 based on electrochemical sensor

The monitoring for atmospheric NO₂ and O₃ using four-electrode electrochemical sensors is reported. We develop a calibration model in order to compensate for the influence of temperature, humidity and zero offset on the sensor''s response. The accurate zero correction of the sensors is achieved by using clean background gas obtained through activated carbon. The parameters of the calibration model are identified by multiple linear regression method. Linear response characteristics of the calibrated sensors are tested and the result is that the sensitivity of NO₂ and O₃ sensors are 3.889 ppbv·mV^-1 and 4.107 ppbv·mV^-1, respectively. Two consecutive days of NO₂ and O₃ observation in the western suburb of Hefei city are implemented, and it is found the concentrations range from 0 to 30 ppbv for NO₂ as well as from 2 to 100 ppbv for O₃. Observation results by the sensors are compared with those by a NO_x/O₃ analyzer, and the regression between them is analyzed. The linear fitting slope is 0.9701±0.0182 with the regression R² of 0.8378 for NO₂, and the linear fitting slope is 0.9850±0.0101 with the regression R² of 0.9431 for O₃. The observation results demonstrate that the calibrated electrochemical sensors can be used for long-term monitoring of atmospheric NO₂ and O₃, which suggests that atmospheric environmental monitoring technology based on electrochemical sensor is promising.