Adviser:  Dr. Anne Thompson  

Surface ozone variability due to El-Niño Southern Oscillation (ENSO) during 1990-2007 is examined at Highveld – a heavily populated region in South Africa with numerous industrial facilities.  The meteorological perturbations of the region are significantly affected by the variability in the sea surface temperature (SST) anomalies of the equatorial Pacific Ocean and therefore could be linearly approximated by ENSO.  Surface ozone is sensitive to the meteorological conditions such as clouds because its production depends on the solar radiation to split NO₂.  Our results find 4 out of 5 air quality monitoring stations measuring ozone that are sensitive to the ENSO in the January-July period where El Niño with dry and warm anomalies acts to amplify the ozone, while La Niña with wet and cool anomalies act to reduce the ozone.  Also over the study period of 18 years three stations display negative ozone trend and two stations show no significant change in the ozone.