Abstract：The atmospheric complex pollution becomes more and more serious, which results in enhanced atmospheric oxidation and accelerated interconversion of pollution trace gases and particles. Differential optical absorption spectroscopy (DOAS) is developed to monitor the characteristics of atmospheric particles in a large scale. The method of differential optical absorption spectroscopy is applied to real-time, online and simultaneous determination concentrations of atmospheric trace gases and extinction coefficients of particles. Method of extinction measurement of atmospheric particles is discussed basing on double optical paths DOAS system. The single optical path DOAS system is discussed for measuring the particle extinction coefficients in this paper. The DOAS system need to be calibrated to measure particle extinction. Firstly, the reference spectrum is measured under the clean atmospheric condition with visibility data. Then the absorption intensity of 550 nm wavelength is recorded to obtain correction coefficient of the the DOAS system. The total absolute optical intensity of atmosphere can be retrieved after calibrating the system parameter. The particle extinction coefficients are obtained by removing the contribution of trace gases and Rayleigh scattering from the total optical intensity. The particle extinctions are obtained from 350 to 700 nm and trace gases concentrations of NO2 are simultaneously retrieved basing on differential principle in the field campaign. The particle extinction coefficients decrease with wavelengths, which is in accordance with Angstrom formula. The research can provide raw data support to study atmospheric heterogeneous gas/particle chemical reaction.
