The Magee Scientific Carbonaceous Aerosol Speciation System CASS operates and simultaneously controls an operation of 2 instruments, i.e. the Total Carbon Analyzer TCA08 and the Aethalometer AE33. The first one collects a sample of atmospheric aerosols on a quartz fiber filter positioned inside a small stainless-steel chamber, at a controlled sampling flow rate of 16.7 LPM. The default sampling time of TCA08 is 60 min, but can be set from 20 min – 24 h, depending on the ambient aerosol concentrations. TCA08 instrument consists of 2 identical parallel channels, which air-flows are being controlled by ball valves and solenoids. A continuous operation is enabled by the following principle of operation: while one channel is collecting its sample, the other channel analyzes an already collected one. Collected sample is flash-heated to convert all Carbon to CO2. The CO2concentration is then integrated to give the Total Carbon (TC) content of the sample.
In parallel AE33 is performing an optical attenuation analysis at 7 wavelengths from near UV (370 nm) to near IR range (950 nm) in order to characterize a Black Carbon (BC/EC) aerosols accumulated on a glass-fiber/PTFE filter tape. On a defined time-base (1 s or 60 s) AE33 reports this BC/EC data to TCA08.
- A unique approach to give the best data.
- NO special GAS, NO CATALYST and NO special quartz GLASS
- CONTINUOUS OPERATION and ANALYSIS of TOTAL CARBON content
- NEAR REAL-TIME determination of CARBONACESOUS AEROSOLS
- SOURCE APPORTIONMENT
- PATENTED technology
- RUGGED and RELIABLE
Determination of TC, BC and equivalent OC and EC fraction
BC data from The Magee Scientific Aethalometer® AE33 is used to determine the equivalent EC fraction:
‘EC‘ = b * BC.
Equivalent OC is determined by a simple subtraction: ‘OC‘ = TC – ‘EC‘.
Proportionality b being region/site specific.