Trace amount formaldehyde gas detection for indoor air quality monitoring

Formaldehyde is not only a carcinogenic chemical, but also causes sick building syndrome. Very small amounts of formaldehyde, such as those emitted from building materials and furniture, pose great concerns for human health. A Health Canada guideline, proposed in 2005, set the maximum formaldehyde concentration for long term exposure (8-hours averaged) as 40 ppb (50 μg/m³). This is a low concentration that commercially available formaldehyde sensors have great difficulty to detect both accurately and continuously. In this paper, we report a formaldehyde gas detection system which is capable of pre-concentrating formaldehyde gas using absorbent, and subsequently thermally desorbing the concentrated gas for detection by the electrochemical sensor. Initial results show that the system is able to detect formaldehyde gas at the ppb level, thus making it feasible to detect trace amount of formaldehyde in indoor environments.