Plant Exposure Chambers for Dust Studies

Abstract

Plant exposure chambers are described which provide for uniform application of dusts at rates simulating those of natural conditions. One set of chambers receives artificial light and is used for short term exposures. A second set of larger chambers receives natural light and provides for dusting plants daily to maturity. A feeder assembly from a Bacho Microparticle Classifier serves as the means of introducing the dust at the top of the chamber. A whirling, counter-airflow stream is introduced a few inches below the feed nozzle to assist in lateral distribution of the dust. Distribution is further enhanced by placing exposed plants on a turntable. Carbon filtered auxiliary air is supplied through a distribution system below the turntable. Variation of dust deposit at different heights above the outer two-thirds of the turntable does not vary more than 5%.