DiSCmini

The all new DiSCmini is a portable sensor for the measurement of particle number and average diameter. Based on the electrical charging of the aerosols. The small size of the DiSCmini handheld makes the instrument particularly suitable for personal carry-on measurement campaigns

Negative Health effects due to nanoparticles appear to correlate particularly well with number concentration or surface. Epidemiological and toxicological studies are still mainly based on total mass, although the health-related effects of particle number concentration are well known. We believe that this contradictory situation is due to the lack of adequate sensors on the market.

This gap is now closed with Matter Aerosol’s handheld version of the “Diffusion Size Classifier” or DiSCmini.  The DiSCmini is a portable sensor for the measurement of particle number and average diameter with a time resolution of up to 1s (1Hz). The simultaneous capture of number concentration and particle size allows the specification of other characteristic parameters, such as the particles surface (Lung Deposited Surface Area, LDSA). This technology is not only available in a handheld version but also as a robust desktop unit (DiSC). In both versions, the battery life of is up to 8 hours, data can be recorded on a memory card, and transferred to a external computer via USB cable.

DiSCmini is particularly efficient for personal exposure monitoring in particulate-loaded work space such as diesel soot, welding fumes, industrial nanomaterials

The DiSCmini is based on the electrical charging of the aerosols. Positive air ions generated in a corona discharge are mixed with the aerosol. The charged particles are then detected in two stages by electrometers. The first detector stage is a pile of steel grids, small particles will preferably deposit on it by diffusion. The second stage is a high-efficiency particle filter which captures all the other particles. The mean particle size can be obtained by analysis of the two currents measured on the stages. The particle count is determined with the total current. DiSCmini detects particles ranging in size from 10 to about 500 nm, while the modal value should lie at  200 nm. The concentration range is from about 1 000 to over 1 000 000 particles per cubic centimetre. The accuracy of the measurement depends on the shape of the particle size distribution and number concentration, and is usually around 10-15% compared to a reference CPC. The unit should be serviced and calibrated once a year.

Unlike other instruments DiSCmini needs neither working liquid of any kind nor radioactive sources and can therefore be operated in any position. Typical applications include the determination of personal exposure in particulate-loaded jobs (diesel soot, welding fumes, industrial nanomaterials) or in vulnerable groups (asthmatics, COPD patients). The development of large area survey grids of ambient air is becoming possible. The small size of DiSCmini makes the instrument particularly suitable for personal carry-on measurement campaigns. The high measurement frequency of 1 Hz allows the instrument to monitor rapid changes in the aerosol. This feature is particularly interesting to local or defined sources of particle generation. The equipment is designed for situations and applications where quick and easy access to particle number concentration and average diameter is desired.