Introduction of Korea Air Pollutants EXposure (KAPEX) Model for PM2.5 and O3

KIYOUNG LEE, Seoul National University

     Abstract Number: 7
     Working Group: Aerosol Exposure

Abstract
Outdoor air contaminants concentration is often used as a surrogate for population exposure. However, people stay most of their times indoors. The time-activity patterns (TAPs) should be considered in the estimation of personal exposure. The Korea Air Pollutants EXposure (KAPEX) model is being developed to estimate population exposures to PM_2.5 and O₃. The input data for the model were 1) outdoor air pollution data from 530 ambient air monitoring stations in Korea, 2) detailed TAP surveys of 12,800 subjects, and 3) the microenvironment-to-outdoor (M/O) ratios of PM_2.5 and O₃ at thirteen microenvironments. The personal exposure can be estimated by the KAPEX model. A field technician simulated a total of 10 TAPs scenarios for each season while carrying portable PM_2.5 and O₃ monitors. From March 2022 to February 2024, a total of 670 person-days of personal exposure monitoring were conducted across eight seasons. Population-weighted personal exposure was calculated by considering the proportion of people for each TAP scenario. The population-weighted personal exposure to PM_2.5 in Seoul ranged from 14.7 to 16.7 µg/m³ across eight seasons without significant difference. The population-weighted personal exposure to O₃ in Seoul ranged from 3.5 to 10.4 ppb across eight seasons. The O₃ exposures were relatively higher in the spring, with 10.4 ppb in 2022 and 7.6 ppb in 2023. The KAPEX model for PM_2.5 and O₃ could be used to estimate population exposure, identify determinants for high exposure group, and evaluate the effectiveness of control policies to reduce personal exposure.