Airborne Measurements of Ozone and Its Precursors over Yeosu-Gwangyang Industrial Areas in the Southern Coast of Korea

Abstract

The purpose of this study is to understand distributional characteristics in the atmospheric concentrations of <TEX>$O_3$</TEX> and its precursors based on data taken at the southern Korean coast. The average <TEX>$O_3$</TEX> concentration in the high altitude was found to range from 32.3 to 90.8 ppb with a maximum concentration of 132 ppb. The ambient <TEX>$O_3$</TEX> concentration was high at altitudes of 1000 m and 500 m above the southern sea near Gwangyang Bay and an industrial area containing emission sources. The daily mean concentrations of <TEX>$NO_y$</TEX> and CO were 6.7-24.2 ppb and 0.152-0.487 ppm, respectively. During the aerial measurement period, the highest mean concentration of <TEX>$O_3$</TEX> was observed on June 1. The aerial measurement results showed that the maximum ozone concentration was observed to be 132 ppb in the high altitude the southernmost part of Yeosu. The measurement of vertical wind fields in the air indicated that <TEX>$O_3$</TEX> formed in the southernmost part of Yeosu was transported by strong southwesterly winds to the northeast of Gwangyang Bay. This led to a ground <TEX>$O_3$</TEX> concentration of over 100 ppb in Jinju, the northeastern part of Gwangyang Bay. On August 9, when the maximum <TEX>$O_3$</TEX> concentration was 50 ppb, the measurement results showed that <TEX>$O_3$</TEX> concentrations were relatively low compared to other days. In particular, low <TEX>$NO_2$</TEX> and TVOC concentrations were observed, both of which serve to form <TEX>$O_3$</TEX> in photochemical reactions.