In the present context, the issue of air pollution has become a debilitating predicament, affecting the ecosystem, climate, and well-being of people ubiquitously. Therefore, this paper primarily investigates the adsorption behavior of PM2.5 (particulate matter with diameter less than 2.5 µm) contaminants, especially NOx (oxides of nitrogen (N), where x = 1, 2), viz. nitrogen dioxide (NO2) and nitric oxide (NO), on the hydrogen-passivated doped (N, F (fluorine)), co-doped NF)/pristine monolayer Armchair Graphene Nanoribbon (AGNR). The results demonstrate that the sensing performance of AGNR strongly depends on the specific type, concentration, and distribution of dopants. The co-doped NF creates additional active sites for adsorption, increases the surface polarity, and modifies the electronic structure of AGNR. It demonstrates an extremely high chemisorption of − 6.92 eV and − 9.56 eV forming strong covalent bonds, and a gigantic amount of ΔQX of + 2.231 eV and + 0.35 eV for NO2 and NO, respectively, at the F site, that enhances the conductivity. Moreover, a metallic transition with a %ΔEG (bandgap variation) of − 100% leads to an increased sensitivity with a high enhancement in the DOS around the Fermi level. Hence, the NF-AGNR proves to be an efficient and reliable sensor for the detection and monitoring of NOx pollutants.