Monte-Carlo 모의실험을 통한 부분 인구집단별 이산화질소와 오존의 노출 및 위해성 평가

Exposure and Risk Assessment of Nitrogen Dioxide and Ozone for Sub-population Groups using Monte-Carlo Simulations

Objectives: Although the risk assessments for nitrogen dioxide (NO₂) and ozone (O₃) have been extensively studied, most of the existing risk assessments were limited mainly to indoor environments such as workplaces, schools, and multi-use facilities. Therefore, integrated risk assessment is needed to consider exposure in all microenvironments, including outdoors. The purpose of this study was to assess the differences in risk among sub-population groups according to time-activity patterns and reported concentrations, as well as the lifetime risk of Koreans. Methods: In this study, we estimated time-weighted average exposure concentrations of NO₂ and O₃ for preschool children, students, housewives, workers, and seniors using residential time and indoor concentrations (house, school or workplace, other), outdoors, and transport by meta-analysis method. The risk for NO₂ and O₃ were assessed by hazard quotient using reference concentrations 30 and 60 ppb, respectively. The risk assessments were conducted through 1,000,000 Monte-Carlo simulations for probabilistic analysis. Results: Preschool children, students, housewives, workers, and seniors spent 91.9, 86.0, 79.8, 82.2, and 77.3% of their day in a house, school, or workplace, respectively. The risk assessment for the lifetime of a housewife and a worker showed that 33.8 and 28.4% of hazard quotients of NO₂ exceed 1, respectively, and more than 99% of hazard quotient of O₃ were less than 1. Conclusions: The risk of NO₂ and O₃ by sub-population group and for the lifetime of housewives and workers were assessed. The risk for NO₂ was higher than for O₃ and showed a different risk by sub-population group. Both NO₂ and O₃ showed a higher risk for housewives than for workers. This study can be used as a basis for lifetime exposure and risk assessment for NO₂ and O₃.