Biogenic and natural components of Saharan dust sampled in Nigeria. Issue 7 (8th August 2020) - Emmanuel Abiye, Olawale
Abstract: Monitoring of airborne PM associated with Saharan dust storms has been implemented in Ile-Ife, Nigeria during characteristic Harmattan weather conditions over southern West Africa. Collected at low flow rates on quartz fiber filters, all samples were equilibrated and gravimetrically analyzed. Particle size was determined through Scanning Electron Microscopy (SEM) coupled with an ISIS X-ray detector. Concentrated organic extracts from the dust-laden filters were analyzed by Gas chromatography/Mass Spectrometry (GC/MS) for the purpose of characterizing polycyclic- and aromatic-hydrocarbon content. Obtained mass concentrations (predominantly in the range 280–450 µg m −3 with the exception of 780 µgm 3 recorded on a certain day) were well above the daily limits of the WHO standard. Particles sizes were mostly between 10 and 20 µm with a few below 5 µm on the filters analyzed by SEM, indicating the possibility of Saharan dust with adsorbed fractions being capable of penetrating to the lower lungs. The results from the organic analysis carried out in this study indicated that a number of both aromatic and aliphatic hydrocarbons were adsorbed to the airborne PM collected at Ile-Ife. The most occurring aromatic hydrocarbon was quinoline (MEiQ); a heterocyclic aromatic amine and a member of a family of hydrocarbons known to be mutagenic and carcinogenic.