Differential optical absorption spectroscopy employing scattering material as gas cell

A compact nitrogen dioxide (NO2) detection system is developed based on differential optical absorption spectroscopy (DOAS) using light emitting diode (LED) as the light source. Alumina ceramic, with properties of highly scattering and low absorption in the wavelength region of 430 ∼ 450 nm, is utilized as the gas cell to make the system extremely compact. Nitrogen dioxides with various concentrations are measured and the concentrations are retrieved by multiple-linear-regression (MLR) method. The results show that the system presented is robust, compact, and promising for future industrial applications.