title: National-scale exposure prediction for long-term concentrations of particulate matter and nitrogen dioxide in South Korea.
abstract: The limited spatial coverage of the air pollution data available from regulatory air quality monitoring networks hampers national-scale epidemiological studies of air pollution. The present study aimed to develop a national-scale exposure prediction model for estimating annual average concentrations of PM10and NO2at residences in South Korea using regulatory monitoring data for 2010. Using hourly measurements of PM10and NO2at 277 regulatory monitoring sites, we calculated the annual average concentrations at each site. We also computed 322 geographic variables in order to represent plausible local and regional pollution sources. Using these data, we developed universal kriging models, including three summary predictors estimated by partial least squares (PLS). The model performance was evaluated with fivefold cross-validation. In sensitivity analyses, we compared our approach with two alternative approaches, which added regional interactions and replaced the PLS predictors with up to ten selected variables. Finally, we predicted the annual average concentrations of PM10and NO2at 83,463 centroids of residential census output areas in South Korea to investigate the population exposure to these pollutants and to compare the exposure levels between monitored and unmonitored areas. The means of the annual average concentrations of PM10and NO2for 2010, across regulatory monitoring sites in South Korea, were 51.63 μg/m3 (SD = 8.58) and 25.64 ppb (11.05), respectively. The universal kriging exposure prediction models yielded cross-validated R2s of 0.45 and 0.82 for PM10and NO2, respectively. Compared to our model, the two alternative approaches gave consistent or worse performances. Population exposure levels in unmonitored areas were lower than in monitored areas. This is the first study that focused on developing a national-scale point wise exposure prediction approach in South Korea, which will allow national exposure assessments and epidemiological research to answer policy-related questions and to draw comparisons among different countries.
authors.affiliation: Institute of Health and Environment, Seoul National University, Seoul, South Korea. Electronic address: puha0@snu.ac.kr.
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Geography, Seoul National University, Seoul, South Korea.
authors.forename: Insang
authors.initials: I
authors.lastname: Song
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis / Q000706:statistics & numerical data*; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D006801:Humans; D008962:Models, Theoretical; D009585:Nitrogen Dioxide / Q000032:analysis*; D052638:Particulate Matter / Q000032:analysis*; D056910:Republic of Korea
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D009585:Nitrogen Dioxide
keywords: Exposure prediction; Korea; National model; Nitrogen dioxide; Particulate matter