LAUSR

AbstractThe meteorological conditions associated with air pollution episodes on South Africa’s Highveld were studied using Ozone Monitoring Instrument (OMI) and Atmospheric Infrared Sounder (AIRS) satellite estimates, MERRA2 reanalysis model products, and in situ weather data. Surface-layer sulfur dioxide (SO2) and nitrogen dioxide (NO2) display high concentrations during winter (May–July) and provide a focus for statistical analysis of monthly and daily time series. Highveld area-averaged monthly model SO2 was temporally correlated with boundary layer height (correlation coefficient of −0.76) and temperature lapse rate (+0.65) for the period of 1980–2015, but relationships with winds were weak. Daily Highveld area-averaged satellite NO2 was related to dewpoint temperature (−0.59) and exhibited pulsing in the range of 7–24 days for 2005–15. High concentrations of these short-lived locally generated air pollutants were found over and southeast of Johannesburg as a result of urban and industrial emissions. ...