The CASS redefines carbonaceous aerosol measurement by uniting the Total Carbon Analyzer and Aethalometer into a seamless, automated solution. It offers near real-time data on organic and elemental carbon, total carbon, brown and black carbon, and biomass burning contributions, with flexible sampling from 20 minutes to 24 hours. With no need for special gases or quartz components, CASS simplifies operation while delivering high-resolution data for air quality, climate, health, and emissions research.

• Online, near-real-time determination of TC, BC, EC, OC, BrC and biomass burning fraction (%BB)
• Optical BC analysis at 7 wavelengths (370, 470, 520, 590, 660, 880, 950 nm) combined with thermal TC analysis
• AE33 DualSpot™ technology corrects for spot loading effects and enables source apportionment
• Uses ambient air as carrier gas with no fragile glassware or special gas supplies
• 8.4" color touch-screens with graphical interface, network-ready for remote management and data transfer
• Rugged, all-steel, fully-enclosed 19" rack chassis for unattended operation of one month minimum

Measurement Principle

Parameter	Specification
BC measurement	Optical analysis with continuous collection of aerosol on filter and simultaneous measurement of attenuation of transmitted light at 370, 470, 520, 590, 660, 880 and 950 nm
TC measurement	Thermal analysis with flash-heating of sample collected on a quartz filter to convert all Carbon to CO2
OC derivation	OC = TC - EC, derived in near-real time by subtraction
Source apportionment	Discrimination of Black Carbon from fossil fuel versus biomass combustion via two-component model in AE33

Specified Performance of AE33

Parameter	Specification
Analytical sensitivity of BC	0.03 µg/m3 @ 1 min, 5 LPM (or 0.015 µg/m3 in HS mode) — proportional to time-base and sample flow rate settings
Detection limit of BC (1 hour)	<0.005 µg/m3
Detection range of BC	<0.01 to >100 µg/m3

Specified Performance of TCA08

Parameter	Specification
Analytical sensitivity of TC	<0.5 µg C
Detection limit of TC	<0.1 µg C/m3 for 1-h timebase, 16.7 SLPM flow
Detection range of TC	<0.03 µg/m3 to >300 µg/m3

Sampling Flow Rates

Parameter	Specification
BC/EC sampling flow rate	Adjustable from 2 to 5 LPM, provided by closed-loop stabilized internal pump and two mass flow sensors
TC sampling flow rate	16.7 SLPM (1 m3/h), provided by closed-loop stabilized internal pump

Operator Interface

Parameter	Specification
Display	8.4" color touch-screens with status indicator LEDs
Interface	Graphical User Interface with basic data display and control, advanced screens for detailed reporting and parameter setup; network ready for remote management and data transfer

Data Output & Storage

Parameter	Specification
Output	Digital data via RS-232 COM port and Ethernet; network ready for remote management and data transfer
Timebase (BC/EC)	1-second (1 Hz) or 1 minute
Timebase (TC/OC)	20 minutes to 24 hours
Storage	Data written to internal memory once every timebase period; transferable over network or via manually inserted USB drive

Quality Control and Assurance

Parameter	Specification
Flow calibration	Automatic or manual sample flowrate calibration using an externally-attached calibrator
Optical validation	Validation of optical performance using kit of neutral density filters
Zero air test	Pre-programmed built-in zero air / clean air test for TC and BC

Physical Specifications

Parameter	Specification
Dimensions	78 x 48 x 57 cm
Weight	89 kg
Electrical power supply	100-230 VAC, 50/60 Hz (auto-switching)
Power consumption	625 W
Vacuum pump	Internal
Construction	Modular hardware in a fully-enclosed 19" rack mount chassis, hermetically sealed

Accessories

Parameter	Specification
Available accessories	Neutral Density Optical Filter validation kit Ambient meteorological sensor PM2.5 inlet (2.5 µm @ 5 LPM) ALICAT FP-25 flow calibrator with communication cable

CASS Specifications  Download