Numerical analysis of volatile organic compounds concentration and evaluation of hazard index in Bangkok, Thailand

• Main Author: Wisit Thongkum
• Other Authors: Natchanok Pala-En
• Language: English
• Published: Mahidol University. Mahidol University Library and Knowledge Center 2023
• Subjects: Air quality management > Thailand > Bangkok; Volatile organic compounds > Environmental aspects
• Online Access: https://repository.li.mahidol.ac.th/handle/123456789/89569
• Institution: Mahidol University

Monitoring data of conventional air pollutants, measured from 2008 to 2013 in Bangkok, were used to formulate an equation for predicting BTEX and 1,3-butadiene concentrations. It was found that the model performed well and predicted the overall concentration of all air toxic compounds except 1,3-butadiene. Three different spatial interpolation techniques namely, ordinary kriging, the inverse distance weighted (IDW), and spline were tested in order to find the most appropriate scheme to provide the best interpolated results for this study. A cross validation and several statistical parameters were employed for selection. Results indicated that in general, IDW performs much better than the other techniques. The impact zone was defined as an area having annual average concentration of benzene higher than the Thai ambient air quality standard for benzene (1.7 μg/m3), which had decreased from the year 2008 to 2013. The calculated results of hazard quotient (HQ) and hazard index (HI) for the year 2008 to 2013 were less than 1. The decreasing tendency of the area having HI > 0.25 from the year 2008 to 2013 was also illustrated. This could be explained by a success of mitigation measures for VOCs management policy such as the implementation of EURO IV standards. These findings elucidate the effectiveness of changing of fuel quality on the reduction of air toxic concentration in the Bangkok environment.