Changes in NOx and O-3 concentrations over a decade at a central urban area of Seoul, Korea

Abstract

This study aims to explore trends of NOx (NO + NO2) pollution over ten years (2004-2013) at an urban monitoring station at Yongsan in Seoul, Korea. The mean concentrations (in nmol/mol) of NO, NO2, and O-3 measured over the entire study period were 25.3 +/- 730, 36.9 +/- 1.76, and 17.5 +/- 1.31, respectively. The decadal trend of these pollutants exhibited statistically significant, but contrasting, results with downward NO and NOx trends and upward O-3 trends throughout the study period. Correlation studies and principal component analysis (PCA) explained association of NO and NO2 with traffic related pollutants (CO, PM, and SO) at a statistically significant level while O-3 exhibited patterns correlated with meteorological parameters. The overall results of this study indicate that the decadal trend of NO and NO2 was highly dependent on automotive related pollution, while O-3 concentration was influenced by both the availability of NO and meteorological conditions. (C) 2015 Elsevier Ltd. All rights reserved.