Determination of Aerosol Particle Size Distribution using Electrical Differential Mobility Analyzer (DMA)

Determining the size distribution of the particles for assessing their effects on human health and their control mechanisms is very effective. One of the most important equipment used in determining particle size distribution is the DMA. In this study, in addition to the design and construction of a DMA, the size distribution measurement of aerosol particles was carried out.

In this experimental-laboratory study, according to the theoretical principles, the geometric dimensions and operating conditions of the DMA were determined by Fortran programs. The design of the technical drawing of the DMA was done using the Salidworks-2017 software. The DMA designing was performed by studying the size distribution of 12 ranges of DOP particles in 15 voltages.

The results of applying different voltages to the DMA showed that one range of particles size had the highest number of particles in the output of the DMA at each voltage. As the number of particles with the size of 0.26-0.3 µm at 3500 volts and those larger than 2 µm at 9000 volts is the highest at the output of the DMA.

DMA systems are a robust tool in determining the particle size distribution. As by knowing the required voltage to separate a specific size of the particles, the DMA will be able to specify the spectrum of unknown particles.