Technical Abstract: Greater understanding of the mechanisms affecting ammonia volatilization from reused broiler bedding is needed to determine pathways for mitigating ammonia emissions. A chamber acid trap (CAT) system was developed to provide an improved laboratory method for determining ammonia volatilization from litter or cake samples and for assessing treatment technologies to decrease ammonia losses from poultry litter. The CAT system offers precision control of air flow rate through sample chambers as well as straightforward, precise determination of the amount of nitrogen (N) volatilized. This article outlines the basic set-up of the CAT system and provides component list and construction details needed to build the system. This system can be utilized and modified for researching specific mechanisms, involving physical, chemical, or biological treatments, effecting ammonia volatilization from litter or cake