Characteristics and dispersion modeling of VOCs emitted from the tank farm of petroleum
refi nery complex were evaluated in this study. Gas phase VOCs within aboveground storage
tank from all types of petroleum raw materials and products were sampled by the Tedlar bags
prior be transferred to 6-Liter evacuated canisters and analyzed to determine their types and
concentrations using the Gas Chromatography Mass Spectrophotometer (GC/MS) in accordance
with the US.EPA TO-15 compendium method. Results indicated that alkane was the dominant
compound in which pentane is the major contributor in total VOCs. Fraction of the concentration
of pentane in total VOCs was then used to estimate its emission for further used as an input
to evaluate the ambient ground level concentration of pentane through the simulation of the
AERMOD dispersion model. Predicted 1-hr average concentrations were calculated to the
5-minutes average using the concept of the peak to mean concentration with the objective to
evaluate the extent and magnitude of odor impacts caused by pentane. Results indicated that
the highest predicted concentrations of pentane within the modeling domain simulated under
the existing operation of the refi nery were exceeded their RfC and odor threshold. Alternative
mitigation measures to reduce emission of pentane were evaluated and compared with the
existing business as usual of the refi nery. Results suggested that adding of the secondary seal
to the fl oating roof of crude oil storage tank will be the most appropriate measure taking into
consideration its success in decreasing both of the emission and ground level concentration of
pentane as well as demonstrate as the cheapest capital cost per unit of ambient concentration
reduction. This study highlights the important in elucidating the source-receptor relationship
which will assist in quantifi cation of the contribution of emission sources towards the ambient air concentrations. Eff ectiveness and appropriate of mitigation control scenarios to be applied for
industrial air pollution management should be taking into consideration not only their success in
emission control but also on their achievement in reducing level of pollutants in the environment.