free radical

Principle of free radical detector: The measurement of HONO concentration in the atmosphere is carried out using wet chemistry method. The basic principle is to use an absorbing liquid and utilize the diffusion between gas and liquid to convert HONO in the sampled gas into nitrite (NO2-), which is then measured using dual channel long path absorption spectroscopy (LOPAP). Long path absorption spectroscopy (LOPAP) is a widely used wet chemical method for measuring the concentration of gaseous nitrous acid in both laboratory research and field observations.