[nanoPost] Industrial Hygiene Sensor for Measuring Worker Exposure to Nanoparticles

Company Finland

Growing use of nanoparticles in several fields of industry, including textile, electronics, glass manufacture etc. has wakened industrial hygiene authorities for the need to measure and monitor nanoparticles in working places. Old methods based on mass concentration of harmful agents are not feasible when looking at nanoparticles. Nanoparticles carry basically no mass, but have enormous surface area and number concentrations. New techniques need to be developed to monitor the potential health effects of nanoparticles.

Existing optical measurement technologies are insensitive to nanoparticles due to their small size that scatter no light. Additionally expensive and fragile laboratory instruments like CPC (Condensation Particle Counter) for nanoparticle measurements cannot be used in harsh factory environment. There is a clear need for low cost measurement instrument that is real-time, affordable, robust, sensitive for nanoparticles and suitable for industrial hygiene applications.

The company has developed a new sensor-type device for in-situ nanoparticle measurement in working places. The sensor is a unique non collective flow through particle detection  device, based on known and well defined electrical particle detection principle.

In the sensor a corona needle is located inside a small-volume charging chamber with perforated walls. This chamber is located inside a constant flow tube, and the whole measurement volume flows through the chamber. High voltage power supply, located outside the chamber, is used to generate a corona discharge inside the chamber, and particles going through the chamber obtain an electrical charge by means of diffusion charging. A sensitive electrometer is then used to measure the charge leaving the chamber with the particles. This signal is relative to the total active surface area of particles flying through the charging chamber, and independent of particles initial charge level.  

The sensor is a non-collecting flow-through device, thus minimizing the need for cleaning and maintenance. Due to its simple construction sensor offers an affordable solution for industrial hygiene measurement needs of nanoparticles.