Impactors, Anderson

This appears to be the case as is shown in a study of data from two sources. Table VII and VIII describe a 480 Mw and a 575 Mw unit, which were treated subsequently with flue gas conditioning agent. Figure 4 5 are, respectively, the baseline and treated bar graphs of particulate emissions from the unit of Table VII collected by standard Anderson impactors. Similarly, Figure 6 and Figure 7 are the bar graphs (before and after treatment) from the unit of Table VIII. 

Finlay W, Stapleton K. Undersizing of droplets from a vented nebulizer caused by aerosol heating during transit through an Anderson impactor. J Aerosol Sci 1999 30(1) 105-109. 

Figure 4 The effect of spacer length on dose dehvery. Fine (< 4.7-pm) and coarse (> 4.7-pm) budesonide particles delivered from a pMDI with a metal spacer of different lengths. The aerosol was analyzed by an Anderson impactor (U.S. throat) 2 s after actuation (28 L/min). The optimal ratio between fine and coarse particles was obtained with a spacer of 13 cm for this particular pMDI. Other pMDIs will have different optimum spacer sizes, depending on vapor pressure.

Figure 5 The effect of spacer volume on dose delivery. The aerosol from a budesonide pMDI was analyzed by the Anderson impactor (U.S. throat) 2 s after actuation (28 L/min) through Nebuhaler and Babyhaler, both of which had been primed to prevent electrostatic effects. Both spacers are of similar length but have different diameters (80 versus 50 mm). The aerosol was airborne for a longer time in the spacer with the larger diameter correspondingly, the total dose was larger, mainly due to an increased coarse particle dose.

Measurements on aerodynamic sizes of atmospheric aerosols and associated radionuclides were carried out with Anderson 2000, Inc., 1-ACFM Ambient Impactors with or without the Anderson low-pressure modification, as well as with Sierra model 236 (six-stage) high-volume impactors (HVI). The 1-ACFM design operated at 28... 

Impactors with various designs as well as different types of impaction surfaces are in use (e.g., see Chow, 1995). Examples include the Lundgren impactor, the Anderson sampler, the Mercer impactor, and the Uni-... 

Anderson, T. L., D. S. Covert, and R. J. Charlson, Cloud Droplet Number Studies with a Counterflow Virtual Impactor, J. Geo-phys. Res., 99, 8249-8256 (1994). 

Solid surface impactor with a rotating collection surface or staged plates (Anderson-Slite)... 

Figure 3 Individual stage plates and inlet from the Anderson Cascade Impactor showing the pattern of radioactivity on the plates following sizing of a radiolabeled pMDI formulation. The plates and inlet were placed on the planar gamma camera face and imaged to measure the amount of deposited radioactivity. The plates were subsequently washed with solvent and assayed using UV spectroscopy to obtain the amount of drug deposited.

Fig. 6.26. Anderson cascade impactor a — suctional view, b — characteristics of the separation of aerosol particles at different stages (1-6). A — air flow, B — health hazard region, C — safe area, penetration to lung is not likely...

A cascade impactor operating at 15 L/min would provide an ideal instrument to employ in this standard. Unfortunately, no such device is available. Furthermore, even it were, an impactor operating at 15 L/min would not be able to cope with extension smdies requiring lower airflow rates in, for example, pediatric applications. There are a limited number of devices which operate at lower flows of 1, 2, or 3 L/min of these, the Graseby Anderson 290 series impactor was selected and, in collaboration with the manufacturer, was modified to accommodate nebulized aerosol. This low-flow impactor has additional physical features that help to produce a meaningful estimate of nebulized droplet size, including... 

A. A. Anderson, A Sample for Respiratory Health Hazard Assessment. Am. Ind. Hyg. Assoc. /, 27 (1966), 160-165. Commercial information on the Anderson sampler is available from 2000, Inc., 5899 South State Street Salt Lake City, Utah, USA 84107. K. R. May,/, Sci. Instrum, 22 (1945), 187. Commercial information on the May cascade impactor is available from Casella Corporation see reference 21, or BGI Incorporated see reference 42. 

---