Shape Analysis of Indoor Free Settling Particulate Matters

On the basis of the Area-Perimeter Method, the profile fractal dimensions of the indoor free settling particles were calculated by using fractal geometry theory. Using optical microscope, the grain projection of micro-particles were gotten. With image analysis software, grain shape of air particles were analyzed. And the character of air particles was also analyzed with its special cause of formation. The results showed that: grain shape of air particles could be expressed by fractal dimension. And the character was getting more obvious when the particle was getting smaller. The shape fractal dimensions of the micro-particle ranges from 0.869 to 1.048. The values of fractal dimension decreased with the increasing of the sampling time, and the character was getting less obvious. It is found that the higher percentage of the finer particles is associated the higher profiled fractal dimension values of micro-particles.