Behavioral characteristics of polyhexamethyleneguanidine (PHMG) particles in aqueous solution and air when sprayed into an ultrasonic humidifier

Sunju Kim; Seonkyeong Park; Hyeri Jo; Seungwhan Song; Seunghon Ham; Chungsik Yoon

doi:10.1016/j.envres.2019.109078

Behavioral characteristics of polyhexamethyleneguanidine (PHMG) particles in aqueous solution and air when sprayed into an ultrasonic humidifier

Environ Res. 2020 Mar:182:109078. doi: 10.1016/j.envres.2019.109078. Epub 2019 Dec 23.

Authors

Sunju Kim¹, Seonkyeong Park¹, Hyeri Jo¹, Seungwhan Song¹, Seunghon Ham², Chungsik Yoon³

Affiliations

¹ Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, Republic of Korea.
² Department of Occupational and Environmental Medicine, Gil Medical Center, Gachon University College of Medicine, Incheon, Republic of Korea.
³ Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, Republic of Korea; Institute of Health and Environment, Graduate School of Public Health, Seoul National University, Seoul, Republic of Korea. Electronic address: csyoon@snu.ac.kr.

PMID: 31884194
DOI: 10.1016/j.envres.2019.109078

Abstract

Polyhexamethyleneguanidine (PHMG) is widely used as a disinfectant to prevent microbial contamination in ultrasonic humidifiers in Korea; however, sales have been prohibited by the government after an outbreak of severe lung injury among humidifier disinfectant users. This study was therefore conducted to determine the characteristics of PHMG particles in aqueous solution and to investigate the behavior of airborne particles generated when using PHMG as a humidifier disinfectant. Three types of PHMG were selected (manufactured in Korea, USA, and China), with dynamic light scattering (DLS) used to determine their behavioral characteristics in aqueous solution. To determine the airborne behavioral characteristics, PHMG was diluted to obtain high (62.5-65 ppm) and low (6.25-6.5 ppm) concentrations, and then real-time monitoring instruments were used to measure the effect of using a diffusion dryer and thermodenuder to control moisture in a cleanroom. A polycarbonate filter sample was analyzed by field emission-scanning electron microscope-energy dispersive spectrometry (FE-SEM-EDS) to determine the particle morphology. The DLS intensity results for the three products showed a slightly right-shifted (~100 nm) bimodal distribution relative to the airborne particle size distribution. The size of the airborne PHMG particles increased during the spraying due to aggregation, with the particle size of aggregated particles confirmed by FE-SEM to be approximately 20 nm or more. As the PHMG concentration increased by 10 times, the airborne concentrations measured by the real-time monitoring instrument increased by 2-3 times for nanoparticles, and by 45-85 times for 1-10 μm particles during humidifier operation; however, 99% of the particles generated could be classified as PM₁. Without ventilation, even after operating the humidifier, the PHMG particles could be airborne for about 2 h until the background concentration was reached. Therefore, we found that the airborne behavior was affected by PHMG concentration. Products from different manufacturers had no effect on the airborne behavior.

Keywords: DLS; FE-SEM; Humidifier disinfectant; PHMG; Real-time monitoring instrument; Ultrasonic humidifier.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

China
Guanidines* / chemistry
Humidifiers*
Republic of Korea
Ultrasonics*

Substances

Guanidines
polyhexamethyleneguanidine