NOAA’s Air Resources Laboratory (ARL) conducts applied research into atmospheric chemistry and transport processes, air-surface exchange, and numerical model development and evaluation. ARL requires the purchase of one trace gas analyzer to measure nitrogen oxides, specifically NO and NOY (total reactive nitrogen), in the atmosphere at a site to be determined in the Northeast United States. This analyzer must be capable of fast response (less than 60 seconds) and high sensitivity (detection limits less than 0.05 parts per billion by volume), and must measure both NO and NOY via the technique of ozone chemiluminescence. The analyzer must be relatively sophisticated and capable of measuring NO and NOY rapidly, with high accuracy and precision. At the same time, the analyzer must be easy to use, reliable, and robust, for long-term, unattended operation with minimal oversight and maintenance.