Environmental hazards associated with release of emission from petroleum refineries have caused serious concerns for the host communities. The study focused on the assessment of the contribution of Nigerian refineries to the ambient air quality. Total emission of toluene, ethyl benzene and xylene (TEX) from Nigerian twenty-six (four existing and twenty-two proposed) refineries were estimated using emission factor approach, under no-control measure (worst case scenario) option. Results showed that the four existing refineries emit 2.90 × 1013 tons of toluene, 1.93 × 1013 tons ethyl benzene and 1.06 × 1013 tons per year while the twenty-two proposed refineries have the capacity of releasing annually 9.17 × 1013 tons of toluene, 6.69 × 1013 tons of ethyl benzene and .95 x 1013 tons of xylene. If operated at full capacity, the total estimated TEX emission from the existing refineries stood at 5.89 × 1013 tons/year while the proposed refineries have the potential of adding additional 2.01 × 1014 tons/year. These concentrations were considered as environmental menace that could have adverse health challenge of the residents of the host communities. Some technologically driven measures to control and subsequently reduce TEX emission from these refineries were suggested.