Evaluation of a modified CEA Instruments, Inc. model 555 analyzer for the monitoring of formaldehyde vapor in domestic environments

Abstract

Modifications have been made to the experimental design, chemical reagents, and operational protocol for a CEA Instruments Model 555 analyzer to optimize the performance of the instrument for formaldehyde (CH₂O) monitoring. The improved sensitivity and reliability of the modified instrument enhances its suitability for quasi-real-time monitoring of domestic environments with low CH₂O concentration levels (0.01–0.2 ppm). Calibration data taken at sub-0.1 ppm CH₂O levels yields a detection limit of ∼0.01 ppm. The CH₂O response of the instrument is insensitive to changes in humidity, but demonstrates a serious temperature dependence between 16 and 38°C. Calibration data taken at room temperature, is, however, applicable between 16 and 28°C if a specific operational protocol is observed. Field results taken in 3 dwellings with low CH₂O concentration levels are reported. The performance of the modified CEA Instrument compared favorably with an environmentally controlled, reference, air-sampling unit.