AETHALOMETER® AE36s

New wavelengths for improved characterization of Brown Carbon

To improve the real-time characterization of Brown Carbon absorption, two additional wavelengths are introduced in the AE36s: the 400 nm enhances the resolution of absorption in the gap between 370 nm and 470 nm; the 340 nm extends the measurement range in the UV spectrum.

Aerosol light absorption measurements are crucial for evaluating the impact of aerosols and their mixing state on radiative forcing. Absorption spectral dependence can be described by the absorption Ångström exponent, which is used to characterize the light absorbing aerosols: Black Carbon and Brown Carbon and their sources.

AE36s provides new dimensions to the research of Brown Carbon, properties of aerosols at new wavelengths, comparison to measurements at fluid state, determination of mass absorption cross section and many more.

AE36s can maintain its incomparable accuracy and stability in different environmental conditions - 500% improvement. Relative humidity changes are affecting the performance of all filter-based instruments. Fluctuating relative humidity levels, e.g., due to air conditioning, can cause variations in characteristic of the filter tape, which can lead to inaccurate measurements. However, AE36s is designed to be robust against relative humidity changes and RH compensation mechanism enables reliable and accurate performance in varying environments.

AE36s is designed to provide a multitude of valuable and insightful data, while requiring minimal resources. Real-time data visualization provides a quick glance at the most important data for the last week. Self-cleaning procedure gives you peace of mind by reducing buildup of dirt and other contaminants that may affect the data quality. Several safety and diagnostic features make sure the instrument is running optimally while having complete control over instrument and quality of data. New status control is implemented for automatic data validation, providing the best foundation for reliable and accurate data analysis and reporting. AE36s is ready to be seamlessly connected wherever you are, using the RAS module in updated CAAT software.

PATENTED AUTOMATIC COMPENSATION FOR FILTER LOADING EFFECT

Sample collection and analysis is performed on two filter spots simultaneously at different flow rates. Mathematical combination of the data eliminates the filter loading effect and provides continuously corrected data in real time with no discontinuities at filter advances.

This compensation depends critically on the aerosol composition and properties. It must be determined in real time from the measurement data, as it cannot be predicted in advance.

The parameters derived from this analysis also offer additional insights into aerosol composition and aging.

The Aethalometer® analyzes the sample at 9 optical wavelengths from the ultraviolet (340 nm) to the near-infrared (950 nm). Optical absorption by different aerosol components have different variations across the spectrum: most notably, the differences between diesel exhaust and emissions from biomass burning. The 9-wavelength data allows for a separation of these components, providing a real-time speciation of the aerosol sources and a determination of their origins.

The Aethalometer® source apportionment algorithm uses filter loading compensated data (DualSpot) considering different loading effect across the spectrum, resulting in true and accurate real-time source apportionment.

AE36 can be combined with Total Carbon Analyzer TCA08 to Carbonaceous Aerosol Speciation System CASS: a revolutionary OC/EC analyzer that measures:

• Total Carbon Content (TC),
• Elemental Carbon content (EC),
• Organic Carbon content (OC),
• and the Black Carbon content (BC).

Furthermore, using the advanced TC/BC(λ) method CASS can be used to monitor a complete fingerprint of carbonaceous aerosols, including primary and secondary organic aerosols.

HIGH TIME RESOLUTION (1 HZ) ANALYTICAL RESPONSE

Sampling, analysis, and all calculations are performed at a fundamental rate of 1 Hz. Standard reporting time base of 1 second or 1 minute permit the identification of temporal patterns and the study of direct emission sources such as engines, stoves, etc. Data may be aggregated into averages of 1 hour, or other intervals, for air-quality reporting. All data and internal diagnostics are stored internally with an instrument capacity of many years.

Data validation is an essential part of quality assurance and control (QA/QC). Auto data validation eliminates the need for manual data validation, which can be time-consuming and prone to human error. New status controls are implemented for Automatic data validation that provides the best foundation for reliable and accurate data analysis and reporting.

The optical performance of the Aethalometer may be validated by the Neutral Density Optical Filter Kit, consisting of four precision optical elements whose absorbance is traceable to fundamental standards. Software routines measure the optical intensities at all wavelengths and compare the analysis instantly with the original reference values. Other built-in test programs offer routine checks of stability and leakage. These features provide Quality Assurance that is essential both for routine monitoring and research use.

The Aethalometer® is the instrument most-used in the world for research of absorption optical properties of aerosols and Black Carbon. Thousands of studies have been carried out with Aethalometer that contribute to science and raise awareness of carbonaceous aerosols and their impact on human health and climate change.