Preliminary experiments are carried out to characterize the droplets generated in two aerosol-generating health care procedures,i.e.taking nasopharyngeal aspirates（NPA）and nebulizer therapy.Glass slides and water-sensitive paper（WSP）are used to collect large droplets when taking NPA.Droplet stain-marks on glass slides are counted under a microscope,and then a size analysis is performed.During nebulizer therapy dust monitors are used to detect small droplets and droplet nuclei at different positions around the nebulizer and in the room.From the preliminary results it is found that taking NPA can stimulate coughing and generate large droplets.Nebulizers can generate more than tens of millions fine droplets ranging from 0.3 to 20 μm per minute,a large volume of which can escape from the holes on the nebulizer＇s facemask and disperse in the whole room.Droplets coagulate on the inner surface of the mask and the volunteer＇s face,suggesting a great possibility of drug solution contamination by patients＇ secretion during nebulizer therapy.
