The report summarizes the activities conducted at the Environmental Monitoring Systems Laboratory's wind tunnel test facility in RTP, NC from January 1985 to July 1986. During this period, the wind tunnel test procedures proposed for PM(sub 10) reference and equivalent methods (49 FR 10454) were evaluated and revised. Several shortcomings in the particle sampling and analysis procedures used in the wind tunnel test facility were identified and eliminated. Specifically, the aerosol distribution system was redesigned, the differences in concentration measurements between an isokinetic high-volume sampler and an array of isokinetic sampling nozzles were investigated, the repeatability of replicate isokinetic sampler measurements was determined, the precision of the analytical technique (fluorometry) was determined, and velocity and turbulence profiles were measured over the range of wind speeds used for testing.