To investigate the absorption of atmospheric PAH in orange jasmine leaves, Murraya paniculata (L.) Jack and the potential of orange jasmine leaves to monitoring atmospheric PAH by evaluating the relationship of measured concentrations of atmospheric PAH and calculated atmospheric concentration PAH estimated from leaves. Four sampling sites were selected from Bangkok roadsides, which are Phayathai road, Chula soi 62 (Patumwan junction), Ngamwongwan road (Phongphet junction), Paholyothin road (Saphan Khwai junction) and Rama IV road (Kasemraj junction). The potential of leaves as bioindicator of atmospheric PAH was studied by comparing the calculated PAH concentration estimated from the orange jasmine leave and the concentrations of atmospheric PAH which collected from the same locations by high volume air sampler. The result indicated that total PAH in orange jasmine leaves at Saphan Khwai was the highest concentrations (82.46 mg/kg), and Kasemraj and Phongphet were slightly difference (70.71 and 65.59 mg/kg, respectively), while Patumwan area was considerably the lowest (63.99 mg/kg). And the regression analysis of relationships between calculated and measured PAH in the air was clearly showed good linear relationships (r² > 0.70, p = 0.028) in lower molecular weight, which were ACY, ACE, FLU, PHE and ANT since they had relatively high vapor pressure and mostly presented in gas phase. While the concentration of higher molecular weight PAH which mostly occurred in particulate phase had low correlation coefficient (r² < 0.6, p = 0.230).
