source identification, spatial distribution and ozone formation potential of benzene, toluene, ethylbenzene, and xylene (btex) emissions in zarand, an industrial city of southeastern iran

Introduction: benzene, toluene, ethylbenzene, and xylene (btex) as the ozone precursors have been classified as the hazardous air pollutants because of their negative effects on humans. this article presents the results of the first assessment of source identification, spatial distribution and btex's ozone-forming potential (ofp) in zarand. materials and methods: the current study was conducted at 30 geographically separated locations, in zarand, kerman, southeastern iran, during the summer and winter of 2020. btex samples were collected using passive samplers and then analyzed using gas chromatography-mass spectrometry (gc-ms). spatial variations were surveyed using the kriging method in gis. results: total btex levels (79.26±26.87 μg/m^3) during the summer were greater than their levels in the winter (37.38±29.18 μg/m^3). the ranking of btex level in all samples followed as: toluene>m,p-xylene>o-xylene>ethylbenzene>benzene. the overall ofp of 374.79±135.08 μg/m^3 in the summer and 172.61±148.81 μg/m^3 in the winter were more than 100 μg/m^3 as recommended guideline defined by world health organization (who), with toluene having the highest potential. conclusion: according to the results of the present study, btex relative abundances in all samples were toluene>m,p-xylene>o-xylene>ethylbenzene>benzene. despite of concerns among inhabitants and workers, benzene concentration was lower than other studied species. control measures such as management of fuel use in motor vehicles and industries and development of green space must be adopted to attenuate the level of toluene in the atmosphere in the studied area.