1. Beijing Key Laboratory of Optical Detection Technology for Oil and Gas, China University of Petroleum, Beijing 102249, China
2. Department of Physics, Capital Normal University, Beijing 100048, China
Abstract：The study presented a quantitative investigation in monitoring the fine particulate matter with the aerodynamic diameters less than 2.5 μm (PM2.5) in air with terahertz (THz) technique. Absorption bands were observed and linear relations were obtained between PM2.5 mass and absorbance at selected frequencies with correlation coefficients R of ~0.86. The utilization of principal component analysis (PCA) proved the similar absorption trend in the entire range with increasing PM2.5 mass. In order to improve the prediction precision, we employed other three statistical methods including partial least square (PLS), support vector machine (SVM) and back propagation artificial neural network (BPANN) for the quantification of PM2.5. Compared with single linear models, statistical models had larger prediction correlation and smaller errors. For BPANN model, R and root-mean square error (RMSE) achieved 0.999 as well as 0.016 mg in training and 0.912 as well as 0.207 mg. Therefore, the combination of THz technique and statistical methods represents high precision of prediction and really can act as an effective tool to monitor PM2.5 together with other normal approaches.
基金资助: the National Key Basic Research Program of China (2014CB744302), the Specially Funded Program on National Key Scientific Instruments and Equipment Development (2012YQ140005), the China Petroleum and Chemical Industry Association Science and Technology Guidance Program (2016-01-07) and the National Natural Science Foundation of China (11574401，61405259)
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