Abstract
When bioaerosols float in the atmosphere, due to static electricity generated by collisions and friction, particles agglomerate. By using the cluster-cluster aggregation model, the structures of aggregated particles were established at different stages in the aggregation of bioaerosols. Moreover, extinction parameters of the aggregated particles were calculated by using the discrete dipole approximation method, thus obtaining the bioaerosol mass extinction coefficient. The results demonstrate that aggregation of bioaerosols can decrease the mass extinction coefficient. When there are three, or four, original particles in each of the aggregated particles, the mass extinction coefficients of bioaerosols decrease to 50% and 25% of those before aggregation. Porosity of aggregated particles is a key factor affecting the mass extinction coefficient: the greater the porosity, the smaller the mass extinction coefficient a bioaerosol.
