Emission Factors for Abrasive Materials

Abrasive blasting materials, such as coal slag garnet and copper slag, are often used for cleaning metal surfaces to remove rust and to prepare a surface before the application of a coating. The pre-blast and post-blast (spent) abrasive materials contain traces of heavy metal constituents such as Cr, Mn, Ni, Pb Fe, and Ba. Hence, the health risk associated with the resultant particulate emissions is a source of concern. Emission factors are often used to estimate emissions from such industrial operations. Since the development of the emission factors for uncontrolled abrasive blasting operations, prepared for US EPA in 1995, several attempts were made to derive emission factors for particulates. This paper will provide an overview of several relevant studies – where emission factors were proposed/ and or could be used to determine particulate emission factors. The studies reviewed include wind tunnel pilot-scale studies which simulate open air activities such as paint removal of bridges and vessels. The studies also include semi-enclosures (similar to spray booths with open ends). Lastly, the paper will propose new emission factors for several abrasive blasting materials that are based on the analysis of airborne experimental data rather than pre-blast test data.