DEVELOPMENT AND EVALUATION OF A SMALL ACTIVE OZONE SAMPLER

Current methods for monitoring ambient and microenvironmental ozone in clude continuous measurement instruments, such as UV photometric and c hemiluminescence monitors, open-path diffusion optical absorption spec trometer, and passive sampling devices. This paper introduces a new sm all active ozone sampler that utilizes a single etched glass denuder a s the collection substrate. The denuder is coated with a solution cont aining the nitrite ion that reacts with ozone to produce nitrate. It i s attached to a small personal pump driven by a 9-V battery. When comp ared with UV photometric measurements, the active sampler demonstrated very good accuracy (active sampler/UV photometer = 0.94-1.00) and pre cision (%P = +/-4.1-6.5%) under laboratory and ambient conditions for sampling period from 1 to 60 h. The Harvard active ozone sampler perfo rmed as well as the Timed Exposure Diffusion sampler, the only other a ctive ozone sampler currently in use. Sampler performance was found to be insensitive to variations in relative humidity (active sampler/UV photometer approximate to 1.00 at 20-80% RH) except at very low relati ve humidity (active/UV photometer = 0.81 at 12%). A low limit of detec tion of 10 ppb.h allows for sampling at very low concentrations.