A COMPARISON OF ACTIVE AND PASSIVE SAMPLING DEVICES FOR FULL-SHIFT AND SHORT-TERM MONITORING OF FORMALDEHYDE

The objective of this work was to identify suitable methods for personal sampling of formaldehyde in ambient air at sub-ppm levels. Experiments were conducted to survey several of the commercially available monitors and to compare them to the more established ''active'' methods, which are based on a variety of different chemistries: chromotropic acid, 2-(hydroxymethyl)piperidine, and 2,4-dinitrophenylhydrazine. Experiments were conducted in a laboratory plexiglas exposure chamber. Stable formaldehyde concentrations were generated by heating alpha-polyoxymethylene in a refillable, high-permeation rate diffusion tube. The experiments were designed to determine the suitability of the monitors for short-term and time weighted average (TWA) monitoring for formaldehyde. Short-term sampling was performed at nominal concentrations of 0.3 and 2 ppm. TWA sampling was performed at nominal concentrations of 0.3, 0.5, and 1 ppm. A total of 6 passive and 5 active methods were evaluated. Several devices were capable of measuring formaldehyde at the current (0. 75 ppm PEL, 2 ppm STEL) regulatory limits. However, only one device, the GMD 570 series badge, based on 2,4-dinitrophenylhydrazine, consistently met the Occupational Safety and Health Administration's performance criteria and was suitable for personal monitoring at the American Conference of Governmental Industrial Hygienists' 0.3 ppm ceiling.