Measurement of NMHCs at Oki Island, Japan,: An evidence of long range transport

The analysis of C-2-C-6 non-methane hydrocarbons (NMHCs) was conducted at r emote site in Oki Island, Japan from July 24-August 10, 1998. Lower molecul ar weight hydrocarbons, C-2-C-5 alkanes, ethene, acetylene, propene, and is oprene accounted for more than 90% of the total measured hydrocarbons. The study of trajectory analysis revealed that East Asia Pacific Rim Region is significantly contaminated from the anthropogenic emission transported from Asian continent by rapid convective movement of air masses. Air masses ori ginating from Pacific Ocean and crossing over Japanese Island were rich in C-3-C-5 hydrocarbon. On the contrary, the air masses arriving directly to t he site without any prior continental influence were more aged maritime air masses.