CRYSTALLINE SILICA

Air Control Techniques, P.C. has developed an ambient PM4 crystalline silica monitoring method as an extension of U.S. EPA’s ambient PM2.5 particulate matter monitoring method.  With the sponsorship of the California Construction and Industrial Minerals Association and the National Stone Sand & Gravel Association, Air Control Techniques, P.C. used the new crystalline silica monitors to develop PM4 crystalline silica emission factors for crushers, screens, and conveyor transfer points.  We have also used the monitors in upwind-downwind sampling programs.


The data compiled using the PM4 crystalline silica monitors are helping mining sources in California demonstrate compliance with the chronic exposure reference limit adopted in 2005 by the California Office of Environmental Health Hazards Assessment (OEHHA).


A summary of the PM4 crystalline silica emission factors are available in the November 2009 issue of the Air & Waste Management Journal.