1. School of Mathematics and Physics，China University of Geosciences，Wuhan 430074, China
2. Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
Abstract：SO2 emissions from industrial smokestacks and ship exhausts is an important factor causing air pollution. SO2 is easy to be oxidized into sulfuric acid fog or sulfate aerosol, which produces acid rain and seriously endangers the balance of atmospheric, ecological environment and harms human health. The existing SO2 optical remote sensing measurement techniques, such as Raman scattering lidar, Differential absorption lidar (DIAL), Fourier transform infrared (FTIR) spectroscopy, Differential absorption spectrometer (DOAS), high-resolution spectral imaging techniques, etc., are all difficult to satisfy with the application requirements in consideration of a high temporal resolution, high spatial resolution and portable mobile, etc. In recent years, the ultraviolet SO2 camera imaging detection technology gets rapid development for its high precision and strong practicability. With features of high temporal resolution and strong spatial resolution, this technology can directly get pollution gas concentration distribution in the two-dimensional space and the emission rates over time by analyzing image's spatial information and the correlation between SO2 concentration, which makes it play an important role in monitoring environmental pollution. This paper carries out researches based on the ultraviolet SO2 camera imaging detection technology, which focuses on the measurement principle and influencing factors, instrument design and experimental methods, inversion algorithm and result comparison. The main achievements are as follows: (1) combining the narrow-band filter's narrow-wave window, measuring ultraviolet absorption of SO2 near 310 nm by using ultraviolet cameras, the ultraviolet imaging remote sensing theory model is established, and the measurement principle that the ultraviolet imaging remote sensing image detection technology acquires SO2 concentration is introduced; (2) the influence of different incident angle for the filter center wavelength and transmittance curve is discussed by placing the filter in front and back of the lens, from which it was found that camera system sensitivity to SO2 is less influenced by the incident angle when the filter is placed in the back of lens that; (3) the influence of solar zenith angle on SO2 concentration image inversion is analyzed, and the necessity of real-time calibration of SO2 concentration inversion curve is clarified; (4) the UV imaging remote sensing detection apparatus is designed based on the above theoretical analysis and the experiment research of UV imaging remote sensing monitoring SO2 emissions are carried out. The images of the SO2 concentration is obtained by using the 2-IM method to fit the artificial sky background by using the standard calibration of the SO2 Optical depth; (5) DOAS technology is used to monitor the SO2 emissions simultaneously. And the SO2 concentration results obtained by DOAS technology and by the UV imaging remote sensing technology are compared, which shows that the tend of the concentration information calculated by the two methods are consistent. This proves the accuracy of the measurement results of the UV imaging remote sensing monitoring technology and shows the great application prospect of this technology in remote sensing monitoring of industrial smokestacks and ship exhausts pollution.
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