Bio-optic gas sensor (Bio-sniffer) for residential formaldehyde (with ppb-level lower sensitivity)

A bio-optic gas sensor (bio-sniffer) with UV-LED and formaldehyde dehydrogenase (FALDH) for gaseous formaldehyde (FA) was developed and applied for on-site assessment of residential FA. The bio-sniffer measures FA as a fluorescence of reduced nicotinamide adenine dinucleotide (NADH) which is the product of formaldehyde dehydrogenase reaction. The detection limit of the bio-sniffer for gaseous FA was 2.5 ppb (parts per billion), which is enough lower for the purpose of evaluating residential FA from building materials and furniture. The bio-sniffer was also applied to measure phytoremediation of FA vapor with N. E. “Bostoniensis”. The FA level in the measurement chamber decreased down to the detection limit (2.5 ppb), which is lower level than FA level of room air (12 ppb), within 95 min and the value increased to FA level when the chamber was vented.