Data gaps will leave scientists ‘in the dark’: How load shedding is obscuring our understanding of air quality

concentrations of pollutants are within acceptable levels for human health. For example, the 24-hour average standard for PM 2.5 (particulate matter with an aerodynamic diameter smaller than 2.5 µg/m 3 ) in South Africa is 20 µg/m 3 – this may be compared to the more stringent World Health Organization guideline of 5 µg/m 3 . 14 Data available on SAAQIS go through data validation processes and are checked for zero drift, which, if identified, is corrected based on values from the most recent in-situ calibration. In accordance with prescribed standard operating procedures, suspicious data spikes, negative values and other questionable data points are removed