An ultra-sensitive detection system for sulfur dioxide and nitric oxide based on improved differential optical...

Area of Science:

• Environmental Science
• Analytical Chemistry
• Spectroscopy

Background:

• Sulfur dioxide (SO2) and nitric oxide (NO) are key air pollutants.
• Accurate monitoring of these gases is crucial for environmental protection.
• Existing detection methods often struggle with cross-sensitivity and complex environmental factors.

Purpose of the Study:

• To develop a highly sensitive detection system for simultaneous SO2 and NO monitoring.
• To overcome cross-sensitivity challenges in the 200-230 nm wavelength range.
• To improve the environmental adaptability of the detection system.

Main Methods:

• Utilized deep ultraviolet differential optical absorption spectroscopy (DUV-DOAS) in the 200-230 nm range.
• Developed a novel spectrum superposition theory for NO differential optical density (DOD) decomposition.
• Investigated and modeled the effects of gas temperature and humidity on concentration retrieval.

Main Results:

• Achieved a detection limit of 60 ppb for SO2, among the best reported.
• Achieved a detection limit of 7 ppb for NO, utilizing its most sensitive absorption peak.
• Developed and validated compensation models for gas temperature and humidity, enhancing system adaptability.

Conclusions:

• The DUV-DOAS system effectively monitors ultra-low concentrations of SO2 and NO simultaneously.
• The novel spectrum superposition method successfully resolves cross-sensitivity issues.
• The developed compensation models significantly improve the system's environmental adaptability for real-world applications.