Fiberoptic Formaldehyde Field Sensors for Industrial Environments: Capitalizing on Evanescent-Wave Spectroscopy

Formaldehyde is an indoor air pollutant that is widespread across many industries. The established implication of formaldehyde in respiratory conditions and its carcinogenicity pose a risk to millions of workers in the wood and textile industries. We have developed an optical sensor based on the evanescent wave absorption of light by the tailored formaldehyde-sensitive cladding of a modified commercial plastic optical fiber. This known spectroscopic technique, in combination with the inexpensive plastic optical fibers, has proven to be a powerful tool for formaldehyde monitoring. Sensor prototypes following that principle are being tested in two Spanish plywood board production plants. The manufactured fiberoptic sensors have been designed to meet the requirements of in situ, continuous, and unattended occupational FA monitoring with a detection limit of 250 mu g/m(3) (0.20 ppm).