Chemical composition, main sources and temporal variability of PM1 aerosols in southern African grassland

Abstract

Southern Africa is a significant source region of atmospheric pollution, yet long-term data on pollutant concentrations and properties from this region are rather limited. A recently established atmospheric measurement station in South Africa, Welgegund, is strategically situated to capture regional background concentrations, as well as emissions from the major source regions in the interior of South Africa. We measured non-refractive submicron aerosols (NR-PM1) and black carbon over a one year period in Welgegund, and investigated the seasonal and diurnal patterns of aerosol concentration levels, chemical composition, acidity and oxidation level. Based on air mass back trajectories, four distinct source regions were determined for NR-PM1. Supporting data utilised in our analysis included particle number size distributions, aerosol absorption, trace gas concentrations, meteorological variables and the flux of carbon dioxide. © 2014 Author(s).