HR: 0830h
AN: A11F-0043    [PDF]
TI: Assessment of the Photochemistry of OH and NO$_{3}$ on Jeju Island during the Asian Dust-Storm Period in the Spring of 2001
AU: * Shon, Z
EM: zangho@dongeui.ac.kr
AF: Dong-Eui University, Dept. of Environmental Engineering, Dong-Eui University, Busanjingu Gayadong San 24, Busan, 614-714 Korea, Republic of
AU: Kim, K
EM: kkim61@empal.com
AF: Sejong University, Dept. of Earth \& Environmental Sciences Sejong University Kun Ja Dong 98, Kwang Jin Goo, Seoul, 143-747 Korea, Republic of
AU: Bower, K N
EM: k.bower@umist.ac.uk
AF: UMIST, The Physics Department, U.M.I.S.T. P.O. Box 88,, Manchester, M60 1QD United Kingdom
AU: Lee, G
EM: gwlee63@naver.com
AF: Hankuk University of Foreign Studies, Dept. of Environmental Sciences, Hankuk University of Foreign Studies 89 Wangsan-ri Mohyun-myon, Yongin, 449-791 Korea, Republic of
AU: Kim, J
EM: jykim@metri.re.kr
AF: Meterological Research Institute, Korea Global Atmosphere Watch Observatory Meteorological Research Institute Korea Meteorological Administration 1764-6 Seungeon-ri, Anmyeon-eup, Taean-gun, Chungnam, 357-961 Korea, Republic of
AB: In this study, we examined the influence of long-range transport of dust particles and air pollutants on the photochemistry of OH and NO$_{3}$ on Jeju Island, Korea ($33.17\deg$N, $126.10\deg$E) during the Asian Dust-Storm (ADS) period of April 2001. Three ADS events were observed during the periods of April 10-12, 13-14, and 25-26. Average concentration levels of daytime OH and nighttime NO$_{3}$ on Jeju Island during the ADS period were estimated to be about 1 $\times$ 10$^{6}$ molecules cm$^{-3}$ and 2 $\times$ 10$^{8}$ molecules cm$^{-3}$, respectively. OH levels during the ADS period were lower than those during the non-Asian-Dust-Storm (NADS) period by a factor of 1.5. This was likely to result from higher CO levels and the significant loading of dust particles, reducing the photolysis rates of ozone. Decreases in NO$_{3}$ levels during the ADS period was likely to be determined mainly by the enhancement of the N$_{2}$O$_{5}$ heterogeneous reaction on dust aerosol surfaces. Averaged over 24 hours, the reaction between HO$_{2}$ and NO was the most important source of OH during the study period, followed by ozone photolysis, which contributed more than 95% of the total source. The reactions with CO, NO$_{2}$, and non-methane hydrocarbons (NMHCs) during the study period were major sinks for OH. The reaction of N$_{2}$O$_{5}$ on aerosol surfaces was a more important sink for nighttime NO$_{3}$ during the ADS due to the significant loading of dust particles. The reaction of NO$_{3}$ with NMHCs and the gas-phase reaction of N$_{2}$O$_{5}$ with water vapor were both significant loss mechanisms during the study period, especially during the NADS. However, dry deposition of these oxidized nitrogen species and a heterogeneous reaction of NO$_{3}$ were of no importance. Key Words: OH, NO$_{3}$, Asian dust storm, ACE-Asia, Jeju Island
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting