AIR QUALITY MONITORING

Effective air quality monitoring requires the ability to capture real time results that are sensitive and selective. Vaporsens's air quality monitor allows for low ppb range monitoring of ammonia and formaldehyde in ambient and indoor air.

The sensing mechanism is a chemiresistor approach: nanofiber sensors change electrical resistance in response to changes in a proximate chemical environment. The nanofibers form a net or porous structure across an electrode pair resulting in a large surface area that specifically “captures” targeted molecules from the gas phase samples through molecular diffusion and surface adsorption.

When the nanofibers capture target molecules, they will either withdraw electrons from the molecule or donate electrons to it, resulting in an increase or decrease in observed current.  Response times for detection are then measured in seconds, not minutes. Over eighty fibers have been developed to date.  Each one responds differently to a chemical or chemical class.  When the nanofiber sensors are combined into an array, their combined responses form a unique signature or fingerprint for each target chemical.  Furthermore, an essentially unlimited number of nanofibers can be developed leading to improved selectivity and sensitivity for a broadening range of target analytes.  Using nanofibers as chemiresistor sensors can overcome previous limitations of other chemical sensor technologies in terms of humidity, temperature, recovery time, selectivity, and sensitivity.