Evaluation of the volatile organic compounds (VOCs) concentration in the city of Khorramabad gas stations using AERMOD and ArcGIS

Introduction: In the present study, the emission of Volatile Organic Compounds (VOCs) from gas stations located in the city of Khorramabad and its impact on the environment was investigated based on the AERMOD dispersion model and the preparation of maps in Geographic Information System (GIS). Materials and methods: 7 gas stations were randomly selected and the values of VOCs emission in two seasons of the year (winter and summer) were examined. The Phochek 5000 direct reading device was used to measure VOC concentrations. R 3.6.3 was used for the data analysis. Results: The results showed that there was no significant difference among the gas stations in terms of VOCs emission (P>0.05). The highest mean concentration observed at gas station No. 6 with 7.7± 6.48 mg/m3 while    the lowest concentration was at gas station number 3 with a concentration  of 0.52±0.18 mg/m3. The results from the anova revealed that there was a significant difference between the seasons in terms of the VOCs emission (P<0.05). The mean concentration of the VOCs was 3.58±2.77 mg/m3 in the summer and 2.53±2.4 mg/m3 in the winter. Conclusion: Based on the results, the highest estimated concentration in the summer was recorded in the vicinity of gas station No. 6, which is located below Imam Hossein square. Due to the proximity of gas station No. 5 to gas station No. 6 as well as being in the direction of the prevailing wind, the concentrations of VOC emitted by these two gas stations will increase the estimated concentration around Imam Hossein square.