# 565 Environmental Wide Range Aerosol Spectrometer

 

Components:
Model 5.405 - 19 Rack Mounted Condensation Particle Counter
Model 5.500 - Classifier “Vienna” Type DMA 
Model 1.190  - 19" Rack Mounted  Aerosol Spectrometer

Gravimetric measurements have shown that the entire part of the mass of fine dust below 0.5 µm does not even total one percent.  But if the particles are counted, 80% of all particles are in the size range below 0.5 µm.  It is not obvious if the particle number or the particle mass has a greater effect on the human health.  A device or system is needed to measure particles over a wide size range.

This mobile system is designed for continuous wide range aerosol studies assessing the ambient particulate concentration.  It utilizes our patented dehumidification system to avoid loss of the semi-volatile fraction at the sample inlet and uses an advanced low water sensitive laser.  This system consists of two particle counters: the Model 190 (19" rack mounted stationary aerosol spectrometer) and Model 5.405 CPC (condensation particle counter) with a Model #5.500 Electrostatic Classifier (”Vienna”-Type DMA) attached to the #5.405 CPC. The use of two particle counters makes it possible to measure the particle concentration over a very high size range. The larger particles (> 0.5 µm), which determine the total mass of aerosol particles, are counted as well as the smaller particles (< 0.5 µm), which determine the total number of the aerosol particles.  That makes this this system suitable for testing air quality under very different conditions.   

The #5.405 measures size ranges from 5 to 350 nm.  The #190 takes a defined air sample by a volumetrically controlled pump and measures the airborne particles continuously for the size ranges 0.25 to >30 µm in 31 size channels.   The software delivers the measured results in particle number per size channel for the complete measuring range from 0.005 to >30 µm.  Over 75 different size ranges can be obtained with this system.

The instruments are housed in a thermo isolated stainless steel weatherproof indoor temperature controlled enclosure for operation in indoor or outdoor environments. The user can interact with the monitor either through a display/keypad or a PC operating the GRIMM supplied software

Aerosol Spectrometer, Model 1.190

Our Model 1.190 aerosol spectrometer rack mounted stationary aerosol spectrometer provides single particle count and size classification in real time. The sample air with various size particles is drawn constantly through the flat light beam, produced by a focused laser diode. Each scattered signal from a single particle is detected by 90-degree by a high-speed photo diode, so particle color changes can be neglected. Each signal is than counted and classified in 31 different size channels by an integrated pulse height analyzer. These counts can be shown on an attached computer.
 

Vienna Type U-DMA

The sample air, passing an impactor and neutralizer enters the sample air inlet at the outer wall. A clean volume of flow controlled air enters the sheath air inlet which assures a clean air flow around the high voltage rod.  When voltage is supplied to the rod the particles are separated according to their electrical mobility.  Only particles with their appropriate charge travel to the rod and into the sample air outlet entering the condensation particle counter (CPC) as monodisperse aerosols.

Condensation Particle Counter

The aerosols enter via the sampling tube to the saturator, where they cross a heated (35°C) N-butyl alcohol saturation pipe. The aerosols are then exposed to the alcohol vapor . Particles and vapor next flow into the cooling condenser unit (10°C) where the supersaturated vapor condenses on all the particles as they pass through. This process increases the particle size. These droplets then cross a laser beam of light optic where each droplet scatters light onto a photo-diode. 

These signals are continuously counted and are expressed as particles/cm³ every second on the LCD panel of the CPC. These counts are then stored as data and may also transmitted via the RS-232 to an external data acquisition device/program.