MEASURING METHOD OF CONCENTRATION IN AIR OF PARTICULATE MATERIAL

PROBLEM TO BE SOLVED: To measure the concentration in air of particulate material by a method the particulate material adhering to a cylinder body is washed to determine a solution mass by a quantitative analysis of the material contained in washing water while air velocity near the cylinder body is measured to determine the efficiency of making the material adhere to the cylinder body. SOLUTION: A cylinder 1 is set at the right angle to air current 2, the cylinder 1 is left alone by a fixed time T and particles 3 of a part of sea salt particles in the air current 2 are made to adhere to the surface of the cylinder 1. The particles are washed by a very small amount of washing water 6 to be recovered as sample 4. Then, a probe of an electric conductivity meter 7 is put into the washing water 6 to measure electric conductivity. The amount W of salt in the washing water 6 undergoes a quantitative analysis. On the other hand, an air velocity meter 5 is set near the cylinder 1 and the average air velocity U in a fixed time T is measured beforehand and an adhesion efficiency (y) is determined from a theoretical approximation formula or approximation curve. The concentration C of salt is determined by the formula of C=W/(D.L.T.U.y), wherein D represents the diameter of the cylinder body, L the length of the cylinder body, U air velocity, T set time and (y) adhesion efficiency.