Analytical Sciences

Discrimination of Ionic Pollutants except Condensation Nuclei of Acid Fog Using an Ultrasonic Humidifier

Keiji YOSHIMURA,* Ryoei KIKUCHI,* Takashi KIMOTO,** Toru OZEKI,*** Kazuhiko IMANO,* Masahiro KAJIKAWA,* and Nobuaki OGAWA*

*Faculty of Engineering and Resource Science, Akita University, 1-1, Tegata Gakuencho, Akita 010-8502, Japan
**Kimoto Electric Co. Ltd., 3-1, Funahashi-cho, Tennoji-ku, Osaka 543-0024, Japan
***Hyogo University of Teacher Education, 942-1, Shimokume, Yashiro-cho, Kato-gun, Hyogo 673-1494, Japan

Fog droplets in the atmosphere are first produced by the activation of cloud condensation nuclei (CCN), which are originally some ionic compound. Subsequently, the nuclei grow by vapor diffusion. Fog droplets are polluted through the activation process and successive diffusion growth and residence (post activation). We cannot distinguish the effects of the two pollution processes of natural fog water samples. We found that fog droplets can be produced artificially without CCN using an ultrasonic humidifier. Because the artificial fog droplets are not polluted by CCN, the movement of the fog droplets in natural air will take up some pollutants in the air. Consequently, the two pollution processes of fog (the activation of CCN and the post activation process) can be discriminated using data from field experiments. This sampling analytical method is extremely important for further research regarding fog, clouds and environmental chemistry.

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