CASS Online Analysis System for Carbon Aerosol Components

systemGeneral OverviewDescription:

The Carbon Aerosol Composition Online Analysis System (CASS) applies the principles of thermal combustion method/optical absorption method, with excellent design, mature technology, simple and reliable operation and maintenance, and is suitable for continuous online analysis and monitoring of carbon aerosol components.

instrumentAdvantages:

*Continuous online measurement of organic carbon (OC), elemental carbon (EC), black carbon (BC), and total carbon (TC) content, and calculation of brown carbon (BrC) content through seven band optical absorption measurement data;

*Real time source analysis of black carbon, analyzing black carbon into two types of sources: biomass combustion (including coal) and fossil fuels. The instrument outputs that biomass combustion (including coal) accounts for BB%;

*It can be widely applied to laboratory/field observations in the fields of air quality monitoring, pollution emission monitoring, pollution source analysis, as well as climate change and human health research;

*The time resolution of measurement data ranges from 20 minutes to 24 hours, which can flexibly meet different measurement needs;

*Not using auxiliary gas, getting rid of tedious high-pressure gas supply, and reducing operation and maintenance costs;

*All metal analysis component design, reliable operation;

*The ultra-low personnel maintenance requirement of once every two weeks is particularly suitable for unmanned automatic observation;

*The instrument interface displays real-time changes in TC, OC, and EC time series, with the proportion of OC and EC, making the measurement results more intuitive;

*The optical absorption measurement method of CASS system has obtained EPA-ETV certification, Slovenia SIQ certification, and the real-time dual point seven band optical absorption measurement technology has been patented (US 8411272, and US 9018583);

*At present, the CASS system has been widely applied around the world, from the Spanish coast to the Loess Plateau in China, from Berkeley streets to the jungles of Brazil;

Instrument composition andworking principle:

The CASS system consists of two parts: a total carbon analysis unit and an optical absorption measurement unit. The total carbon analysis unit adopts dual channel alternating sampling and high-temperature oxidation to convert all carbon components in particulate matter into CO₂Using a non dispersive infrared (NDIR) detector to integrate and determine the total carbon (TC) content of particulate matter. The optical absorption measurement unit adopts dual point measurement technology to overcome the "masking" effect of filter membrane sampling, and continuously measures the aerosol optical absorption of particulate matter at wavelengths of 370nm, 470nm, 520nm, 590nm, 660nm, 880nm, and 950nm with the fastest time resolution of 1 second. Based on the data from two analysis and measurement units, the carbon aerosol component analysis model is applied to calculate real-time measurement data of different carbon components (OC, EC, BC, TC) in particulate matter.

The optical absorption measurement unit of the Carbon Aerosol Composition Online Analysis System (CASS) performs optical detection on aerosol samples at room temperature, which is different from the existing thermal optical OC/EC analysis methods that perform optical detection during programmed temperature rise. Therefore, there will be no "charging" or "pyrolysis" of aerosol samples during the optical detection process. The measurement results of OC, EC, and BC components provided by CASS have unique determinacy and are independent of the temperature rise program during the analysis process. CASS not only enables continuous online analysis of various carbon components in particulate matter, but also provides multi band aerosol absorption characteristic data, providing information for high temporal resolution source identification research.

Technical referenceNumber:

*Data time resolution:

• Total carbon (TC) and organic carbon (OC): 20 min~24 h (optional), default setting is 60 min;
• Elemental carbon (EC), black carbon (BC), biomass combustion contribution rate (% BB): 1 s, 60 s;

*Filter membrane:

• Thermal combustion (TC) measurement unit: 47mm quartz filter membrane;
• Optical absorption measurement unit: glass fiber membrane coated with polytetrafluoroethylene;

*Sampling section:

• Thermal Combustion (TC) Measurement Unit: 16.7 SLPM;
• Optical absorption measurement unit: 2-5 SLPM, adjustable;
• Suitable for PM_2.5Cutting head;

*Operation interface (remotely operable):

• Thermal combustion (TC) measurement unit: 21cm color LED touch screen, status indicator light;
• Optical absorption measurement unit: 21cm color LED touch screen, status indicator light;

*Data output interfaces: RS232, Ethernet, USB data;

*Data storage: Built in memory card, can also be remotely transferred or manually stored to external storage devices;

*Quality control and quality assurance:

• Thermal combustion (TC) measurement unit: calibrated using offline sampling membrane or sucrose solution;
• Optical absorption measurement unit: Use neutral density optical filters traceable to NIST standards to perform optical calibration, dynamic zero point, and noise detection on the instrument;
• Sampling flow calibration and leak detection: Use an external calibrator for manual or automatic calibration;

*Size and weight: 70 × 48 × 60 cm, approximately 55 kg, installed in a 19 inch standard cabinet;

*Energy consumption: 130W, peak 750W (when the hot combustion chamber is working);

*Work environment:

• Power supply: 100~230 VAC, 50/60 Hz;
• Temperature: 10~35 ℃;
• Humidity: RH<90%, no condensation;
• Altitude: 0-3000m;

*Note: The minimum detection limit and measurement range of OC are equivalent to TC, while the minimum detection limit, measurement accuracy, and measurement range of EC and BrC are equivalent to BC.