Design Optimization of a Photoacoustic System for Gas Detection in Exhaled Breath

Exhaled breath analysis is a promising non-invasive approach for detecting disease-related biomarkers, including nitrogen dioxide (NO₂), which is associated with airway inflammation. A compact photoacoustic spectroscopy (PAS) system was developed using a 405 nm LED source and a resonant acoustic chamber optimized for NO₂ detection. Focused optical excitation enhances localized absorption, generating an acoustic signal detected by a MEMS microphone. The system demonstrated a good response to 50 ppm gas variation, supporting its suitability for low-cost breath analysis applications.