In South Korea, many cases of humidifier disinfectant-associated lung injury (HDLI) have been reported among people who used humidifier products containing humidifier disinfectant (HD). The objectives of this study are to estimate both airborne HD concentration in the room where HD was used and the amount of humidifier disinfectant absorbed into the respiratory system. Information and data on the HDs were collected using a structured questionnaire and home environmental investigations include the volume of HD (ml) and hours used per day, concentration of disinfectants contained in the HD brand (µg/ml), volume of the room (m³), assumed ventilation rate (m³/hr) and breathing rate assumed (m³/hr). We used children aged under five years old as a sample and estimated both airborne HD concentrations and amount of HD absorbed into the respiratory system. The estimated airborne concentration of HD in the room ranged from 68 to 369 µg/m³ for PHMG (polyhexamethylene guanidine phosphate) and from 16 to 239 µg/m³ for PGH (oligo (2-(2-ethoxy) ethoxyethyl guanidine). The amount of HD absorbed in the respiratory system per day was estimated to range from 227 to 1,225 µg for PHMG and from 53 to 794 µg for PGH. In conclusion, a great amount of HD was likely absorbed into respiratory system, likely beyond the level of the capacity of the immune system to remove the HD absorbed.

KeywordsCMIT,humidifier disinfectant (HD),humidifier disinfectant-associated lung injury (HDLI),MIT,PGH,PHMG