===Environment===According to the 2005 statistical book issued by the National Bureau of Statistics, Taiyuan scored the fourth worst among China's main cities in air quality, with only 224 days (2004) of ambient air quality equal to or above grade II, after Lanzhou (worse, 204), Jinan (210) and Changsha (219), with 0.175 milligrams/m2 of particulate matter (the most/worst of all main cities) and 0.087 milligrams/m2 of sulphur dioxide (4th worst).