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Test system for analysing the filter efficiency of respirator material. Nebulized particles were distributed evenly in the space within the cabinet by a fan. The units with and without a filter were connected by equal-length plastic tubing (Tygon and polyurethane, respectively) to validated particle counters that sampled air with a yield of 28 L/min while counting the particles. Sampling and counting of particles were performed for 10 min per test.
