A PM_1.0/2.5/10 trichotomous virtual impactor based sampler: Design and applied to arid southwest aerosols part I: Design

A PM_1.0/2.5/10 Trichotomous sampler has been developed to determine if the particles in the saddle point between the coarse and fine particle modes (specifically the 1.0 μm to 2.5 μm size range) are primarily coarse or fine mode particles. The sampler consists of a standard high volume sampler with two high volume virtual impactors (one with a cut size of 2.5 μm and the other with a cut size of 1.0 μm) inserted between the PM₁₀ inlet and the 8x10 inch (20x25 cm) after filter. By using nine 47 mm filters, at various locations within the trichotomous sampler, a technique has been developed for subtracting out the effects of particles smaller than the cutsize of a virtual impactor from the minor flow particle collection.