1. Graduate School of Environmental Studies Nagoya University Furo‐cho, Chikusa‐ku Nagoya 464‐8601 Japan
2. Asia Center for Air Pollution Research 1182 Sowa, Nishi‐ku Niigata‐shi 950‐2144 Japan
3. National Institute for Environmental Studies 16‐2 Onogawa, Tsukuba Ibaraki 305‐8506 Japan