The Lin-Yuan Petrochemical Industrial Park, located closely to a populated area in southern Taiwan, is considered to be a major source of odor events. To evaluate odor impact near the park, establishment of sampling stations specifically for monitoring odor is essential. This study is intended to identify the location of such odor-monitoring stations through actual monitoring of potential odor-causing substances. We also correlate the concentration of the characteristic chemical odorant to the odor concentration perceived by a panel and predicte time and spatial concentrations of the major odor-causing substances using a dispersion model. Air samples were obtained on four occasions from 10 sites that had experienced frequent odor problems in the past. The concentrations of 10 compounds of each sample were quantified with a GC/MS unit. The impact index is introduced as the concentration of the individual compounds divided by the respective odor threshold concentration. In general, there is one specific com...