Tungstic Acid Technique for Monitoring Nitric Acid and Ammonia in Ambient Air

摘要

A new measurement procedure has been applied in field studies for monitoring ambient concentrations of HNO3 and NH3. Preconcentration of these gases as well as separation from their particulate forms is achieved by pulling the sampled air through a diffusion tube coated with the amphoteric sorbent, tungstic acid. Thermal desorption releases NH3 as NH3 and HNO3 as NO2 for analysis in a standard chemiluminescence NOx monitor.