Experimental determination of indoor air concentration of 5-chloro-2-methylisothiazol-3(2h)-one/ 2-methylisothiazol-3(2h)-one (CMIT/MIT) emitted by the use of humidifier disinfectant

Seon Kyung Park, Hwi Soo Seol, Hee Jin Park, Yoon Seob Kim, Seung Hun Ryu, Jaehoon Kim, Suejin Kim, Jong Hyeon Lee, Jung Hwan Kwon

Research output: Contribution to journalArticle

Abstract

A mixture of 5-chloro-2-methylisothiazol-3(2H)-one/2-methylisothiazol-3(2H)-one (CMIT/MIT) had been used as an active ingredient in humidifier disinfectants (HDs). Owing to its high reactivity, the atmospheric concentration of CMIT/MIT, following its use in HD, would be lower than expected assuming that it is removed by ventilation only. In order to evaluate the exposure concentration of CMIT/MIT used as an HD, room-scale chamber studies were conducted under plausible use of three different HD doses at air change rates (ACR) of 0. 3, 0. 5, and 1. 0 h-1 . Atmospheric CMIT/MIT was sampled using two serial impingers containing deionized water after the attainment of steady state. Water samples in which CMIT/MIT was dissolved were concentrated using a cosolvent evaporation method with efficiencies of 35. 5 and 77. 9% for CMIT and MIT, respectively. The estimated air concentration, assuming that all the CMIT/MIT is absorbed in deionized water, increased linearly with increasing emission rate, but was independent of the ACR. This indicates that the removal rate of CMIT/MIT via chemical reactions is more than the removal rate by ventilation. Further investigations on homogeneous and heterogeneous chemical reactions of CMIT/MIT under ambient conditions are necessary to understand the actual exposure concentration of the mixture in HD.

Original languageEnglish
Article numbere2020008
Pages (from-to)1-6
Number of pages6
JournalEnvironmental Health and Toxicology
Volume35
Issue number2
DOIs
Publication statusPublished - 2020

Keywords

  • Biocides
  • Chemical reactions
  • Chloromethyl/methyl-isothiazolinone (CMIT/MIT)
  • Health risk assessment
  • Indoor air

ASJC Scopus subject areas

  • Toxicology
  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis

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