Airborne particle and microbiological human emission rate investigation for cleanroom clothing combinations

The control of airborne particles and bio contaminants is a key factor in several industries in order to avoid product defects, to assure process quality and to protect personnel and outdoor environment. Cleanrooms and controlled environments are spaces with strict control of airborne contaminants and thermo-hygrometric parameters. Humans are one of the main sources of contamination in clean environments. A correct technical clothing system reduces the contamination released by humans. Despite substantial work done in this field, it is difficult to compare previous results due to differences in test rig, procedures, gowning systems and sampling locations. This study implements a dispersal chamber test methodology and an experimental campaign on 7 combinations of technical clothing and undergarments. It presents comparative experimental results of total particle and microbiological contaminants released by humans in terms of emission rate (ER). It is found that ageing factor, sterilization, physical movements, donning and warping type, and materials influence the human ER in clean environments. Sterile garment systems entirely composed of synthetic materials decrease the particle release compared to the non-sterile mixed ones. Sterile garment systems show a better performance, achieving 10 to 30 times fewer particle emission rates in wider movements and almost zero microbiological release. A low human contamination ER benefits the cleanroom design and operation, either reducing the energy consumption or increasing the number of personnel in clean environments.