System and method for detecting aerosol particles in a atmosphere and counting aerosol particles with respect to each particle size

摘要

A particle size distribution measuring system 1 sets a reference voltage in a DMA 300 to a voltage value U, and executes the classifying of aerosol particles based on electrical mobility, in an electric field to which the voltage value U is supplied. When a predetermined condition is not satisfied, an analyzing device 600 causes a sum of the voltage value for the previous classifying (previous value) and the voltage value U to be re-set in the DMA 300 and causes the classifying of the aerosol particles to be executed again. A particle measuring device 400 defines a first measurement result as a measurement result M1, and defines a result of the re-measurement as a new measurement result Mx every time the measurement is thereafter repeated. An analyzing device 600 calculates a ratio of the measurement result Mx to the measurement result M1, and confirms that the condition is satisfied when the calculation result is a prescribed value or smaller, while confirming that the condition is not satisfied when the calculation result is larger than the prescribed value.

主权项

1. A particle size distribution measuring system comprising:
a neutralizer which puts aerosol particles into a charged equilibrium state; a DMA (Differential Mobility Analyzer) which classifies the aerosol particles charged by the neutralizer in a predetermined electric field based on electrical mobility and which, in a state where a reference voltage supplied to form the electric field is initially set to a voltage value U, executes the first classifying of the aerosol particles under the supplied voltage having the initially set voltage value U; an aerosol particle measuring device which measures the aerosol particles classified out by the DMA, by an electrical and/or optical measuring method and outputs a result of the measurement; and a measurement result analyzing device which confirms whether or not a predetermined condition is satisfied, based on the measurement result output by the aerosol particle measuring device, and when confirming that the condition is satisfied, calculates particle size distribution with respect to each particle size from the measurement result output by the aerosol particle measuring device, and when confirming that the condition is not satisfied, executes: (a) causing the DMA, in a state where the voltage supplied to form the electric field is re-set to a sum of the voltage value of the voltage supplied in the previous classifying (previous value) and the voltage value U, to execute re-classifying of the aerosol particles under the supplied voltage having the re-set voltage value; (b) causing the aerosol particle measuring device
(b-1) to output a first measurement result M1 which is the measurement result of the aerosol particles that the DMA classifies out under the supplied voltage having the initially set voltage value U, and(b-2) to output a new measurement result Mx which is the re-measurement result of the aerosol particles that are classified out, every time the re-classifying is executed in the (a) by the DMA; (c) calculating a ratio of the measurement result Mx, which the aerosol particle measuring device is caused to output in the (b-2), to the measurement result M1, which the aerosol particle measuring device is caused to output in the (b-1); (d) confirming that the condition is not satisfied yet when the ratio calculated in the (c) is larger than a prescribed value, to execute the (a), (b), and (c), while confirming that the condition is satisfied when the ratio calculated in the (c) is equal to or smaller than the prescribed value; and (e) when confirming that the condition is satisfied, calculating the particle size distribution with respect to each particle size from the measurement result based on a charging probability for the aerosol particles to be charged by the neutralizer.