A research team led by Professor XIE Pinhua and Professor HU Renzhi at the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, has developed a high-performance laser-induced fluorescence (LIF) instrument for the real-time, selective detection of atmospheric peroxy radicals (HO₂ and RO₂).
The research was recently published in Sensors and Actuators: B. Chemical.
Peroxy radicals are key intermediates in the photochemical production of ozone, particularly through reactions with nitric oxide (NO). Rising near-surface ozone levels have become a major concern for air quality, prompting the need for more precise radical monitoring tools. Existing methods often suffer from interference and inconsistent detection sensitivity, especially in polluted environments.
In this study, the newly designed system addresses these challenges through an optimized detection framework and conditional stability calibration. A specialized reaction cell design enables near-zero NO interference, enhancing measurement accuracy. The detection limit for RO₂ was determined to be 1.08 × 10⁶ cm⁻³ (2σ) with a 60-second integration time.
During a month-long field deployment, the ROxLIF system delivered consistent, high-quality time series of HO₂ and RO₂ concentrations, showing strong agreement with direct ozone production measurements. The results underscore the instrument’s potential for diagnosing ozone formation with high precision.
"This technology will help us better grasp how different environments contribute to radical chemistry and the atmosphere' s ability to clean itself," explained Professor HU Renzhi, a member of the team, "It' s a step forward in diagnosing and ultimately improving air quality.”
(a) Overall diagram of ROxLIF system. (b) Real image of the Laser module. (c) Real image of the Box container. (Image by HU Renzhi)
