The 2007 heavy-duty on road diesel engine particulate matter standards will require that the particulate matter (PM) levels being emitted from the exhaust will be less than 0.01 g/bhp-hr. This ten-fold decrease in the existing regulations created the need for changes in the PM filter-weighing environment and procedures. The Code of Federal Regulations Title 40, Part 86 Subpart N (40 CFR 86) has stated that a weighing environment must meet Federal Standard 209E class 1000 classification. This regulation required a new cleanroom facility in the West Virginia University Center for Alternative Fuels, Engines and Emissions laboratories.;Weighing procedures were determined by the specifications of 40 CFR 86, conducting experiments and by varying procedures to determine the procedure that yielded the lowest variation. The Society of Automotive Engineers (SAE) documentation and Center for Alternative Fuels, Engines and Emissions laboratory procedures for particulate matter filter handling and weighing were also reviewed to assist in the evaluation of procedures that will yield the smallest error. This study compares the particulate matter collection on two types of filter media, dual 70 mm and single 47 mm T60A20 and 47 mm Teflo filter. The average difference between the 70 mm T60A20 and the 47 mm Teflo was determined to be 0.259 g/testphase. The average difference between the 70 mm T60A20 and the 47 mm T60A20 was determined to be 0.205 g/testphase
