Monitoring airborne fly ash by the membrane filter counting procedure

Airborne fly ash can be monitored by the membrane filter (MF) technique. A variation of the asbestos procedure of the National Institute for Occupational Safety and Health is applicable for monitoring airborne fly ash in the diameter range of 0.75 to 15 micrometers. Results of a survey by the MF method of five coal-fired generating plants show as high as 263 particles of fly ash per cm3 of air in the size range of 0.75 to 5 micrometers. Recent literature on toxic metallic elements on fly ash suggest that respirable airborne fly ash is a risk to human health. Because of the importance of fly ash as air contaminants. the MF technique is proposed as a method for monitoring these particles.