Assessment of Some Pollutant Gases in Selected Cities in Crude Oil-Rich Delta State Nigeria

Abstract

Delta state is one of the petroleum-producing states in Nigeria where upstream and downstream exploration activities tend to pollute the environment. While soil and water pollution are regularly monitored, there is a dearth of information on the impact of exploration and related industries on air quality. This study investigated the levels of pollutant gases including ozone, nitrogen dioxide, sulphur dioxide, hydrogen sulphide and ammonia in ambient air samples selected cities (Warri, Ughelli, Sapele and Ugbenu) in Delta state, Nigeria. The concentration of the gases was determined using air sampling instruments equipped with appropriate sensors for selective to each gas. Meteorological parameters were also obtained concurrently during sampling. The results obtained showed that the average concentrations of SO₂, H₂S and NH₃ were all below the National ambient air quality standard (NAAQS) and Federal ministry of environment (FMEnv) regulatory limits. However, the mean concentration of O₃ and NO₂ obtained exceeded the NAAQS and FMEnv regulatory limits of 0.007 ppm, 0.05 ppm and 0.04 ppm – 0.06 ppm respectively. Ugbenu, the control station did not record any value for the pollutant gases. This is as a result of non-availability of industrial activities that emit these pollutant gases in the area. There was a clear seasonal variation, with higher values recorded mostly in the dry season. The field data agreed with global model data on the pollutant gases. The information from this study provides information on the level of these pollutant gases and how the various industrial process may impact their concentration in this region.