Multi-wavelength UV imaging detection system applied for varying environmental conditions: Detection of SO2 as an example

Abstract

We demonstrate a multi-wavelength ultraviolet (UV) imaging detection system for gaseous pollutants with absorption characteristics in the UV band. As a proof of concept, the detection of sulfur dioxide (SO2) was used as an example to develop a method based on UV imaging. The critical component of the system is a highly sensitive CCD array (1024 × 1024 pixels) UV camera with high quantum efficiency (QE) in the UV range (>30% transmission at 200–240 nm, >50% transmission at 240–400 nm), multiple different wavelength bandpass filters (270 nm, 280 nm, 300 nm, and 310 nm for SO2), environmental condition controller (temperature range 278–318 K, relative humidity range 35–85%), and a compact and robust design (362 mL of the gas absorption cell with a 4.2 m optical path length). The advantages of this system are convenient, fast, and can realize visualization. The system was applied for detecting SO2 in various conditions (different concentrations, temperatures, and humidity). After optimization, the detection limit for SO2 detection is 4 ppb, and the uncertainty of concentration measurement is only about 2.7%.