A particle concentration analyzing system for testing particle concentrations in a fluid sample, such as engine emission particle concentration present in the exhaust of an engine. The particle concentration analyzing system includes a condensation particle counter having a saturation chamber, a condenser, and a laser optic particle counter. The analyzing system further includes a working fluid tank, a working fluid pump, and a sampling probe. The system provides a robust analysis system for a user to test vehicle emissions without being highly trained on the device, as the device is protected from misuse. A position sensitive sensor is used to ensure that the system is not damaged if the system is tipped over or placed in a position that would produce false results. Additional features include differential pressure sensors, a sealed and replaceable tamper resistant working fluid tank, a solvent recovery system, an anti-cheat device, and fluid purity sensors.