Technical Bulletin No. 0062: Methods and Experience in the Measurement of Submicron Particles in Source Emissions and the Ambient Air (AQTB)

There is ample evidence of an increasing public concern over (a) reduced atmospheric visibility or loss of visible range, and (b) visible emission plumes with an extended life. This has directed investigative attention to those particles in emissions responsible for the absorption or scattering of light in the atmosphere, or those with a diameter of about 0.001 to 1 micron. Methods commonly used to evaluate the performance of particulate collection equipment normally account for particles of about 0.3 microns and larger. While the bulk of the mass of particulate emissions is accounted for using these procedures, only a portion of the number of particles responsible for light scattering or absorbance are actually accounted for. The attached technical bulletin describes a number of methods that may be used for measuring submicron particles in source emissions and the ambient air. It also describes an extensive field investigation conducted by Southern Research Institute for the National Council under the direction of Mr. Alvin Bird, which used several of these methods, most of which are instrumental techniques.