GAS-BORNE PARTICLE MEASURING SYSTEM

PROBLEM TO BE SOLVED: To provide a gas-borne particle measuring system capable of measuring gas-borne particles by an air-borne particle counter without decreasing accuracy.SOLUTION: A gas-borne particle measuring system which measures particles suspending in gas other than air comprises: a gas-to-air replacement part 1 which replaces a sample gas with air by means of diffusion by partial pressure difference of the sample gas to be measured and air via a porous partition wall; and an air-borne particle counter 2 which measures the particles in the air replaced in the gas-to-air replacement part 1. A pressure difference gauge 10 can be provided for measuring the pressure difference between a sample gas inflow port A and an air inflow port B of the gas-to-air replacement part 1. Furthermore, a changeover valve 12 which selects and introduces the sample gas or air to the sample gas inflow port A can be provided at a position upstream of the sample gas inflow port A of the gas-to-air replacement part 1.