Table 1: List of the prefectures located west of Japan and ozone concentrations from 2006 to 2009.
*hourly mean concentration during daytime
Prefecture Number of stations Annual mean ozone concentrations (ppb)
(1-hr*, max-hr)
2006 2007 2008 2009
1 Hokkaido 23 28.8 38.1 28.5 38.2 29.6 39.0 31.4 40.5
2 Aomori 6 36.7 48.0 36.5 47.0 32.7 42.2 32.3 42.2
5 Akita 5 35.8 45.4 38.0 48.4 36.8 47.3 37.5 47.3
6 Yamagata 10 32.3 44.3 34.1 46.1 32.7 43.9 32.9 44.0
15 Niigata 28 33.9 46.4 36.5 49.6 35.8 47.9 37.4 49.0
16 Toyama 25 36.4 51.3 36.4 50.6 35.0 48.4 33.7 45.5
17 Ishikawa 22 35.0 46.9 37.2 49.5 36.9 49.1 38.5 50.0
18 Fukui 22 31.8 45.5 32.0 45.8 33.6 47.7 33.0 45.6
31 Tottori 3 34.0 45.3 34.3 45.7 33.7 45.3 36.3 47.3
32 Shimane 7 36.9 49.7 38.3 50.1 36.6 48.7 37.9 49.3
35 Yamaguchi 19 30.3 47.2 34.6 52.3 32.9 48.9 35.4 51.1
40 Fukuoka 40 29.7 45.5 33.8 49.9 30.3 45.5 33.6 48.9
41 Saga 9 30.9 45.3 32.0 46.6 33.3 49.1 38.3 52.8
42 Nagasaki 18 34.4 47.3 36.2 49.1 33.8 46.2 37.6 50.3
43 Kumamoto 20 28.2 42.5 32.3 47.4 30.4 45.4 35.3 50.7
46 Kagoshima 9 33.9 48.0 34.6 47.8 32.2 45.1 36.5 50.2
47 Okinawa 4 27.3 34.7 27.7 34.0 27.3 34.3 33.8 41.5