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Canary Gas SMARTOXs detection System


Microdust Pro TM - Aerosol Photometer
Portable Real-Time Aerosol Monitor, Data Logger



         Real-time measurement of airborne particulate concentration

         IAQ Monitoring

         Industrial Hygiene factory monitoring for particulates

         "Walk through" surveys

         Specialist size selective monitoring (PM2.5 and PM10, respirable and thoracic)

         Filter test and aerosol research


         Affordably priced

         Hand held and portable

         Wide range (1 microgram/m3 to 2500 mg/m3)

         Internal data logger

         Graphical on-screen display

         Versatile software included

         Built-in calibration for zero and span

         Option of user defined calibration

         Option of rechargeable (10 hr) or alkaline (20 hr) batteries

         Size specific inlets (TSP, PM10, PM2.5 and respirable)

The Microdust ProTM is the latest development in the science of photometric measurement of suspended particulate concentrations. While instruments of this type have been available since the 1960's, this latest development from Casella Ltd. of Bedford, U.K. represents a step-function advance over all competitive offerings.

The Microdust ProTM measures particulate concentrations using a near forward angle light scattering technique. Infrared light of 880 nm wavelength is projected through the sampling volume where contact with particles causes the light to scatter. The amount of scatter is proportional to the mass concentration and is measured by the photo detector. By using a narrow angle of scatter (12-20 degrees) the majority of light scattered is in the diffracted and refracted components, which minimizes the uncertainty associated with particle color, shape, and refractive index.

Concentration Range
The Microdust ProTM has the advantage that there is only one model which covers the entire measurement range (0 to 2500 mg/m3). It is possible to "fix" the range of the instrument, or have it as an "auto-ranging" device.

The Microdust ProTM incorporates a 128 x 64 pixel graphical backlit display. Dust concentrations are presented in two unique ways:

         Graphical representation - the Microdust Pro is the first real time particle measuring instrument to have a scrolling graph of dust concentrations. The graph is able to show a continuous trace over a number of time-bases. These may be set on the X-axis at 100 seconds, 200 seconds, 15 minutes and 1 hour. The Y-axis range may be auto-ranging or fixed.

         Numerical values - instantaneous concentrations are displayed, as well as values for the Time Weighted Average (TWA) and maximum concentrations. These values can be reset at any time by a "one button" reset.

Each Microdust ProTM is individually factory calibrated using a gravimetric technique. The instrument can be returned to the 'factory' calibration setting, at any time during its life, by the use of a non degradable calibration insert (supplied).

An individual gravimetric calibration is also possible. This involves the collection of a gravimetric (filtered) sample of the dust after it has passed through the probe optics. In this way, two averages are collected over the exposure period. One is from the filter, whilst the other is provided by the averaging function within the instrument. It is then possible to derive the difference in these two figures and correct accordingly.

Additionally, it is possible to store 4 different calibration values within the instrument and select these according to the situation. All these procedures are accessible through the easy menu structure.

The WinDustProTM software offers the user the ability to perform the following functions:

         Create a "profile" for the instrument (logging interval, parameters and "identifier" for multiple instruments). Transfers control profile from the PC to the instrument.

         Recover data from the instrument

         Production of line graphs based upon historical data

         Tabular and report presentation of data files

         Real time presentation of prevailing conditions via the RS232 connection

The Microdust ProTM features an internal logger which can store up to 15,700 data points over 32 separate runs. The logging interval can be set from 2 seconds to 10 minutes. At 2 seconds, it is possible to record 8.75 hours of data; at 5 minutes, this equates to a total logging time of 50 days. Recorded values include:

         Average concentration over the logging period (mg/m3)

         Maximum concentration over the logging period (mg/m3)

         Date and time stamp


Sensing Technique

Near forward light scattering - 880 nm infrared


All instruments provide 0 to 2500 mg/m3 over four ranges as standard


0.001 mg/m3 (1 ug/m3)

Operating temp range

0 to 50 C (non condensing)

Storage temp range

-20 to +55 C


Gravimetric method using 'Arizona Fine' calibration dust (ISO12103-1,A2)

Zero stability

+/- 0.002 mg/m3/C

Span stability

< 0.7% FSD/C



4 x AA / MN1500 cells - Alkaline or rechargeable NiCd

Operating duration

Alkaline (2700mAh) typ. > 20 hrs
NiCd cells (950mAh) typ. > 10 hrs

Battery charging

Internal NiCd fast charger circuitry (with time-out protection)

Charge rate

Fast charge rate 450mA, Standby charge rate 55mA

Power adapter

Universal input voltage range 100-250VAC, 47-63Hz


12VDC @ 0.8A


Analogue Output

0 to 2.5Vdc FSD, 500 ohm output impedance (3 ms update rate)


7 key tactile membrane


Instrument only: 0.97 kg (2 lbs) (complete kit with flight case: 4.5 kg (10 lbs))


Probe: 35 mm dia x 290 mm (1.4 x 11.4 in) total length
Instrument H x W x D: 245 x 95 x 50 mm (9.6 x 3.7 x 2 in.)
Flight case H x W x D: 135 x 490 x 370 mm (5.3 x 19 x 14.5 in)


Factory cleaning required annually depending on measurement conditions



128 x 64 pixel LCD graphics panel with backlight

Displayed values:


Instantaneous reading:

Rolling average concentration over a user selectable period (1 to 60 seconds)

Time weighted average:

Average concentration since power on or reset

Maximum value:

Maximum concentration since power on or reset

Scrolling graphs

100/200 seconds, 15 minutes or 60 minutes (Y axis autoranging or fixed)

Battery voltage

Battery voltage with 'OK'/'Low' status message


Factory calibration

Traceable isokinetic technique (wind tunnel) and ISO 12103-1

User calibration

Four user defined calibration settings available

Routine calibration

Software calibration for zero and span setting
Optical calibration filter supplied (restores factory calibration)

Data Logging:

Internal memory

64K EEPROM providing 15,700 data points

Logging interval

Adjustable from 2 to 600 seconds

Recorded values

Average concentration over logging period
Individual, average and max/min concentrations over logging period

Serial interface

RS232 up to 38.4K baud


WinDustPro provides a friendly graphical interface for instrument configuration, data download and graphical report presentation

Operating system

MicrosoftTM Windows 95, 98 or NT (16 or 32 bit)


IBM compatible PC with RS232 serial port, 8MB RAM, FDD, HDD, VGA colour graphics


Microdust Environmental Enclosure

The Microdust Environmental Enclosure accessory to the Microdust Pro is designed to monitor aerosol or dust concentrations in either indoor environments where security is an issue, or in ambient conditions. Using the enclosure, it is possible to monitor a range of particle sizes (including PM10, PM2.5, respirable or TSP) for up to 24 hours. A filter collects all the sampled dust for gravimetric or chemical analysis and a "retrospective calibration" can be applied to the instrument.

Ordering Information


Microdust Pro kit in carry case - includes calibration insert, clean air bellow, rechargeable batteries (4), power supply, 32 bit software & RS232 comms cable



Environmental Enclosure - includes battery, chamber, pump and inlet


Gravimetric dust adapter


Respirable dust adapter


Size selective adapter


Foam inserts for (PM)2.5, pkg. of 50


Foam inserts for (PM)10, pkg. of 50


Foam inserts for respirable





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