Two types of aerosol generators, the Riker Laboratories metered spray can and the Mistogen EN145 ultrasonic nebulizer, were evaluated by laboratory measurements for application to the in situ calibration of particulate mass monitors for stationary sources. The metered spray can delivers a fixed amount of aerosol each time the valve is depressed. The average mass of propellant and solution in each squirt is 52 mg, and is reproducible within 4%. The volume median diameter was varied from 1.4 to 3.2 micrometers by selection of solute concentration. Because of its simplicity and reproducibility of output, the metered spray may be useful for a variety of applications requiring a portable aerosol source. For calibrating stack beta gauges, larger aerosol output of 5-10 mg is needed, requiring a valve with a metering volume at least ten times larger than present valves. Contact electrification monitors require a test aerosol of 25 mg/cu m at a flow of 1 cu m/min. Appropriate for this application is the ultrasonic nebulizer, which has an output of 50 mg/min, constant to within 8% over a period of hours.

"EPA-600/2-79-191." EPA grant number R 805577010. EPA project officer: John Nader. Includes bibliographical references (pages 41-42).