Improving our atmospheric research measurements is the key to further understanding the processes governing formation and evolution of marine- and continentally-derived aerosols. One such measurement is aerosol size distributions which, as the articles below will demonstrate, have developed improved spatial and temporal resolution to better observe microphysical events such as nucleation and condensation. The instruments used for these measurements include differential mobility analyzers (DMA), scanning electrical mobility spectrometer (SEMS), and radially classified aerosol detectors (RCAD). The effectiveness of these instruments depends on diffusion losses, transmission efficiencies, charge neutralizers, and transfer functions.

Peer-reviewed publications on this topic:

Determination of Differential Mobility Analyzer Transfer Functions Using Identical Instruments in Series (DOI)
W. Birmili, F. Stratmann, A. Wiedensohler, D. Covert, L. M. Russell, and O. Berg.

Five types of different mobility analyzers were experimentally characterized by their transfer functions using particle size ranges between 3 and 200 nm. It was found that the area of the transfer function decreased with particle size for all DMA types and that the gradient of the decrease was different for each of the DMA types.

Intercomparison Study of the Size-Dependent Counting Efficiency of 26 Condensation Particle Counters (DOI)
A. Wiedensohlet, D. Orisini, D. S. Covert, D. Coffmann, W. Cantrell, M. Havlicek, F. J. Brechtel, L. M. Russell, R. J. Weber, J. Cras, J. G. Hudson, and M. Litchy.

Frequent calibration is essential for accurate concentration measurements in individual particle counters. In preparation for ACE1, particle detection efficiency curves for 26 condensation particle counters were investigated to ensure reliable data for comparison at the different sites among the instruments available.

Particle Charging and Transmission Efficiencies of Aerosol Charge Neutralizers (DOI)
David Covert, Alfred Wiendensohler and Lynn Russell.

Three neutralizers commonly used in aerosol research were discussed to characterize the diffusion losses and charging efficiency of each, which is critical for accurate size dependent measurements. Both 85Kr neutralizers failed to bring a singly charged aerosol to equilibrium charge for the range of concentrations and flows reported, at low particle concentrations 85Kr neutralizers were functioning adequately for the purposes of ACE1.