In Taiwan, the annual mean concentration of ozone is constant, but
surface ozone concentration at ozone event days (24 h maximum value of the hour > 120 ppb) have increased significantly attribution ozone event days to reduce (Fig. 1). Some researchers believe this is related to global warming (Langner et al., 2005; Reilly et al.,2007; Joireman et al., 2010; Nema et al., 2012). Ambient ozone is a secondary air pollutant that forms in atmospheric photochemical reactions.