More than 1 million European workers are exposed to formaldehyde (1B carcinogen), being the main sectors concerned the following ones: production and transformation of wood sector, health services and textile industries. Direct-reading monitors based on electrochemical and chemoresistive sensors have problems of sensitivity, selectivity and usually cannot be recovered after exposure to very high concentrations of formaldehyde.

The absence of an official protocol has as consequence the difficulties to achieve an appropriate medical surveillance of workers exposed to formaldehyde.

Solution

A novel fiberoptic colorimetric sensor system for formaldehyde monitoring has been developed. It can be used for in situ, online, unattended monitoring.

Following a substantial bibliographical review, a new, specific medical surveillance protocol for formaldehyde exposed workers has been proposed.

Results

An innovative real-time formaldehyde monitoring system based on the evanescent field absorption of light by a formaldehyde-sensitive cladding of a plastic optical fiber has been developed. The sensor performs 15 min integrated measurements (limit of detection: 0.03 to 0.20 ppmv) followed by an automatic regeneration process by air.

The sensor has demonstrated remarkable performance when installed at a paper impregnation process of an industrial facility and could be easily deployed in other industries and processes where formaldehyde means a relevant occupational risk. Its ruggedness, selectivity and sensitivity, smart auto-regeneration, and low maintenance satisfy the requirements for a powerful analytical tool to in situ monitor formaldehyde levels in industrial environments.

The monitoring system may be easily connected to alarm devices and to specific control measures (e.g. door locking, local exhaust ventilation, etc.) that would be autonomously activated when a threshold concentration be overwhelmed (European Directive 2004/37/EC. Art. 5.k).

Finally, it is worth noting the development of the specific protocol for health surveillance for workers exposed to formaldehyde. The creation of this Medical Evaluation Protocol for exposure to formaldehyde is a considerable step in preventive action, since some of the actions carried out in it allow for the establishment of a potential suspicion of exposure to very low concentrations of this substance, based on the symptoms that the exposed persons could present, having created a correlation table between the symptoms that the workers could potentially present and the environmental concentration of exposure.

Also, this protocol proposes the use of biological indicators that, until now, have been used and developed by research groups.

This project received the financial support of the European Commission’s LIFE Program (LIFE16-ENV_ES_000232)