Particulate matter (PM) can be emitted from stationary point sources, e.g., smokestacks, but it can also come from non-point sources, e.g., vehicles traveling on unpaved roads and agricultural tilling activities. For both types of sources, PM emission factor (EF) inventories were developed to allow policy makers and industries to make decisions in mitigating air pollution. A field campaign was carried out to quantify PM10 EF from open burning/open detonation (OB/OD) in outdoor ambient air. The PM10 EF were obtained by the hybrid-optical remote sensing (ORS) method. The results were in general agreement with independent measurements completed by the USEPA?s Flyer measurement. However, there is substantial difference between existing BangBox OD EF measurement for energetic 2,4,6-trinitrotoluene and hybrid-ORS measurement, which possibly indicates that BangBox EF measurement may not be applicable for predicting actual ambient field OD PM10 emissions. This is an abstract of a paper presented at the 105th AWMA Annual Conference and Exhibition 2012 (San Antonio, TX 6/19-22/2012).