Also, in the current paper, we focus on the evaluation of nocturnal atmospheric extinction coefficient (mag/airmass) and others statistics (time of acquisition, accumulation time, air mass, and HR number is used as a star name only for information..) at Paranal observatory (70 degrees 24'05 '' W, 24(0)37'24 '' S, altitude 2635 m a.s.l, in Chile.). In addition, the rms error of the coefficient has been calculated. It is absolutely needed to evaluate the accuracy of each extinction measurement. For the first time, they were obtained from MASS database photometric processing during 885 nights in the years 2004, 2005, 2006 and 2007. These results will almost lead to complete its characterization. The project is implemented in the frame of the European Southern Observatory contract No. PO 014190/HNEU.