The weekly variations of O3 and NOx during 2008 at CCMand PK in Nanjing (CCM: Caochangmen, PK: Pukou). The zero line presents the average value of O3 or NOx during a week
(from Monday to Sunday), and the concentration anomaly means the difference between the average concentration on any day of a week and the average value of the whole week. The
observed data in the rainy days are not included.