Aerosol Experiment Results Featured in Technical Journal

Sheridan, P., U.S. Department of Commerce/NOAA

Aerosol Properties

Aerosol

Sheridan, P, W Arnott, J Ogren, E Andrews, D Atkinson, D Covert, H Moosmuller, A Petzold, B Schmid, A Strawa, R Varma, and A Virkkula. 2005. "The Reno Aerosol Optics Study: An evaluation of aerosol absorption measurement methods." Aerosol Science and Technology 39(1):1-16.


This magnification shows the size of aerosol particles relative to the pore size of the filter used during one of the study's sampling runs.


This magnification shows the size of aerosol particles relative to the pore size of the filter used during one of the study's sampling runs.

Aerosol particles are gaining increasing scientific attention as a key factor in climate change. Through scattering and absorption of solar radiation, or by altering cloud properties, aerosols have the potential to induce changes to Earth's energy balance. Understanding of this "aerosol forcing" mechanism is limited by uncertainties associated with various techniques used to measure the aerosols. Six papers discussing the results of an aerosol absorption study, co-sponsored by the National Oceanic and Atmospheric Administration and the DOE Atmospheric Radiation Measurement Program, merited the entire January 2005 issue of Aerosol Science and Technology. The Reno Aerosol Optics Study, conducted in June 2002, was designed to compare the performance of many existing and new instruments for the in situ measurement of aerosol optical properties, with a focus on the determination of aerosol light absorption. In general, the study found good agreement between the reference absorption and measurements from the different instruments, though correction schemes were needed for the filter-based techniques.

Using the laboratory controlled environment of The Desert Research Institute in Reno, Nevada, researchers evaluated numerous instruments used for obtaining aerosol property measurements. These instruments included: three cavity ring-down extinction instruments; one classic folded-path optical extinction cell; four integrating nephelometers; two photoacoustic absorption instruments; and five filter-based absorption instruments, as well as numerous other instruments and methods for aerosol microphysical and chemical characterization. Emphasis was placed on determining the representativeness of filter-based light absorption methods, as these are widely used, but, as reflected in the study, require major corrections to the raw attenuation measurements. The majority of the test aerosols were mixtures of kerosene soot and ammonium sulfate, and all tests were performed at low relative humidity (~15-25%).

Aerosol Science and Technology, the official journal of the American Association for Aerosol Research (AAAR), contains the results of theoretical and experimental investigations into aerosol phenomena and closely related material, as well as high-quality reports on fundamental and applied topics. The AAAR is a nonprofit professional organization for scientists and engineers for promoting and communicating technical advances in the field of aerosol research. This organization fosters the exchange of information among members and with other disciplines through conferences, symposia, and publication of Aerosol Science and Technology.

The following RAOS papers appear in the Aerosol Science and Technology, January 2005 edition:

Arnott, W, K Hamasha, H Moosmuller, P Sheridan, and J Ogren. 2005. "Towards aerosol light-absorption measurements with a 7-wavelength aethalometer: evaluation with a photoacoustic instrument and 3-wavelength nephelometer." Aerosol Science and Technology 39(1):17-29

Moosmuller, H, R Varma, and W Arnott. 2005. "Cavity ring-down and cavity-enhanced detection techniques for the measurement of aerosol extinction." Aerosol Science and Technology 39(1):30-39.

Petzold, A, H Schloesser, P Sheridan, W Arnott, J Ogren, and A Virkkula. 2005. "Evaluation of multiangle absorption photometry for measuring aerosol light absorption." Aerosol Science and Technology 39(1):40-51

Sheridan, P, W Arnott, J Ogren, E Andrews, D Atkinson, D Covert, H Moosmuller, A Petzold, B Schmid, A Strawa, R Varma, and A Virkkula. 2005. "The Reno Aerosol Optics Study: An evaluation of aerosol absorption measurement methods." Aerosol Science and Technology 39(1):1-16.

Virkkula, A, N Ahlquist, D Covert, W Arnott, P Sheridan, P Quinn, and D Coffman. 2005. "Modification, calibration and a field test of an instrument for measuring light absorption by particles." Aerosol Science and Technology 39(1):68-83.

Virkkula, A, N Ahlquist, D Covert, P Sheridan, W Arnott, and J Ogren. 2005. "A three-wavelength optical extinction call for measuring aerosol light extinction and its application to determining light absorption coefficient." Aerosol Science and Technology 39(1):52-67.