Air pollution and heavy metal contamination are serious environmental challenges in industrial cities such as Gachsaran City, an oil, gas, and petrochemical hub. Using resistant plant species is a sustainable, low-cost mitigation strategy. This study evaluated heavy metal accumulation (Pb, Ni, Cu) and air pollution tolerance in five dominant tree and shrub species in Gachsaran City. Samples were collected from three stations: city center, Chaharbisheh Industrial Town, and Dousti Park (control). Species were Citrus aurantium, Melia azedarach, Conocarpus erectus, Bougainvillea spp., and Olea europaea. Heavy metals were measured by atomic absorption spectrometry. APTI, API, and bioconcentration factors (BCF, CBCI, MAI) were determined. The results showed metal concentrations in soil and leaves followed Ni > Cu > Pb, with maximum at Chahar-Bisheh Industrial Town, Gachsaran. Melia azedarach accumulated the highest level of Cu and Ni with amount 15.70 and 14.50 mg/kg), respectively. And the Conocarpus erectus accumulated the highest Pb (7.16 mg/kg). Species differences were significant for Ni (P = 0.006) and Cu (P = 0.034), but not Pb (P = 0.47). Melia azedarach had the highest APTI (10.01), while Olea europaea had the lowest (6.08). APTI was strongly positively correlated with RWC (r = 0.87, P < 0.01). API classified Melia azedarach and Citrus aurantium as good, and Conocarpus erectus and Olea europaea as poor. Conocarpus erectus showed BCF > 1 for Pb (1.069), indicating high phytoremediation potential. Melia azedarach and Citrus aurantium are recommended for polluted areas, whereas Olea europaea should be limited near pollution sources.