Journal of Environmental Protection, 2011, 2, 194-197 doi:10.4236/jep.2011.22022 Published Online April 2011 (http://www.SciRP.org/journal/jep) Evaluation of Nitrogen Oxides Pollution in Takamatsu and Utazu Area in Kagawa Prefecture, Japan Shoko Murakami1, Noriko Sakano1, Shigeru Suna2, Fumiyuki Asakawa3, Nobuyuki Miyatake1 1Department of Hygiene, Faculty of Medicine, Kagawa University, Miki, Kagawa, Japan; 2Kagawa Prefectural College of Health Sciences, Kagawa, Japan; 3Kurashiki University of Science the Arts, Kurashiki, Japan. Email:
[email protected] Received December 21st, 2010; revised February 6th, 2011; accepted March 12th, 2011. ABSTRACT We evaluate nitrogen oxides pollution in Takamatsu and Utazu area in Kagawa prefecture, Japan. Annually observa- tions for nitrogen oxides (nitrogen dioxide; NO2, nitric oxide; NO) (1990-2007) were obtained from data base of Ka- gawa prefecture, Japan. Changes in NO2 and NO in Takamatsu and Utazu area were evaluated and compared. In 2007, NO2, NO and NO2 + NO (ppm) in Takamatsu area were higher than those in Utazu area. However, NO2 /(NO + NO2) in Takamatsu area was lower than that in Utazu area. From 1990 to 2007, mean of NO2 in a day over the level of 0.06 ppm was 30 days in Takamatsu area and only one day in Utazu area. Mean of NO2, NO and NO2 + NO was signifi- cantly higher and NO2/(NO + NO2)was lower in Takamatsu area than that in Utazu area. In addition, NO2, NO and NO2 + NO were negatively correlated and NO2/(NO + NO2) was positively correlated with years (1990 - 2007) in Ta- kamatsu area. The level of nitrogen oxides pollution in Utazu area was lower than Takamatsu area.