Norio Arai, Aritaka Matsunami, Kozo Matsumoto, Kuniyuki Kitagawa, Noriyuki Kobayashi and Katsuichi Asai
Daily chromatographic investigation of the nitrogen(I) oxide content of the atmosphere at Ryori in Japan has shown a steep increase in concentration during the 1990s. The incremental increase was 5–9 ppbv, compared with the world-wide estimate for 1975–1985 of 1 ppbv.