Sulfate aerosol generation and characterization for controlled human exposures.

Abstract

Carefully controlled human exposures to ammonium sulfate, ammonium bisulfate, and sulfuric acid aerosols were performed to provide valid data concerning effects of potentially harmful atmospheres at “worst case” ambient and possibly industrial levels. The aerosols were produced by a specially designed generator, based upon the Babington nebulization principle. Volunteer human subjects were exposed to nominal sulfate aerosol concentrations of 100 µg/m3 (mass median aerodynamic diameter [MMAD] of 0.3 µ. and a geometric standard deviation of approximately 2.9) at 31.1°C (88°F), 40% relative humidity, in a 62.3 m3 (2200 ft3) chamber. The chamber was continuously supplied with air at a flow rate of 14 m3/min (500 ft3/min) which was well mixed with the existing chamber air to assure that no concentration gradients existed within the subject exposure zone. Real-time monitoring of aerosol mass and size was performed by a computer-controlled electrical aerosol size analyzer/optical particle counter system. The tot...