Chemical characterization of fine particulate matter, source apportionment and long-range transport clusters in Thohoyandou, South Africa

Abstract

This paper presents a chemical characterization of fine particulate matter in air masses passing through Thohoyandou and further determines their sources. Fine particulate matter (PM2.5) was collected and quantified using gravimetric method. X-ray fluorescence, Smoke stain reflectometer, Optical Transmissometer and Scanning Electron Microscopy- Energy Dispersive X-Ray Spectroscopy were used to determine the chemical and morphological composition of the particulate matter. The source apportionment was done using principal component analysis while the HYSPLIT model was used to depict the long-range transport clusters. The mean of concentrations of PM2.5, soot, black carbon and UVPM were 10.9 μg/m3, 0.69x10-5 m-1, 1.22 μg/m3 and 1.40 μg/m3, respectively. A total of 24 elements were detected in the PM2.5 with Pd, Sn, Sb, Mg, Al and Si being the dominant elements. SEM-EDS have shown the presence of irregular, flat and spherical particles which is associated with crustal material and industrial emissions. Source apportionment analysis revealed six major sources of PM2.5 in Thohoyandou namely, crustal materials, industrial emissions, vehicular emissions, urban emissions, fossil fuel combustion and fugitive-Pd. Air parcels that pass-through Thohoyandou were clustered into four. The major pathways were from the SW Indian Ocean, Atlantic Ocean and inland trajectories. Clusters from the ocean are associated with low concentration, while inland clusters are associated with high concentration of PM2.5. The PM2.5 occasionally exceeds the WHO daily guideline in Thohoyandou and the sources of PM2.5 extend beyond the borders. This study recommends that further studies need to be carried out to assess the health impacts of PM2.5 in Thohoyandou.

Health Risk Assessment of PM2.5 and PM2.5-Bound Trace Elements in Thohoyandou, South Africa

“…Due to technical issues two PM 2.5 measurements were missing, for 23 and 26 March 2018. The sampling process has been described in detail by Novela et al [29].…”

Temperature modifies the association between air pollution and respiratory disease hospital admissions in an industrial area of South Africa: The Vaal Triangle Air Pollution Priority Area

“…The range of daily PM 2.5 levels in the VTAPA during 1 January 2013 -29 February 2020 was higher than those recorded by the South African government at 21 ambient air quality monitoring stations in 5 provinces in 2012 (4.9 to 43.3 μg.m -3 ) (Altieri and Keen (2019). PM 2.5 levels were also lower during April 2017 to April 2018 in Cape Town, a large coastal city in the country, and Thohoyandou, a rural non-industrial town in the north of the country (Novela et al, 2020;Williams et al, 2021). PM 2.5 levels were lower in Pretoria, the administrative capital of South Africa during April 2017 to February 2020 (Adeyemi et al, 2022;Howlett-Downing et al, 2022).…”

“…There is a lack of studies in Africa that reported on BC levels and their health effects. The mean BC level (1.28 μg.m -3 ) in Thohoyandou was lower (Novela et al 2020). A study from Nairobi, Kenya reported a higher mean of 2.7 μg.m -3 for BC (Gaita et al 2014)…”

Particulate Matter (PM2.5) Characterization, Air Quality Level and Origin of Air Masses in an Urban Background in Pretoria

“…Urban background sites are commonly used to depict the typical exposure to the population without a dominating influence of nearby point sources. Particulate matter samples were taken every third day from April 18, 2017 to April 17, 2018, spanning four seasons, with a start and stop time of 9:00 a.m. to 9:00 a.m. the next day (due to the inability to stop the pumps at midnight, which necessitated the option of sampling time), as done in other studies (Novela et al 2020;Williams et al 2020;Adeyemi et al 2021). A total of 122 PM2.5 samples and 25 duplicates were collected on 2.0 µm PFTE (Zefon International, Inc ocala, FL34474 USA)., PTFE supports (Zefluor) 37 mm filters for 24 hours, during the sampling campaign.…”

“…Further research into the impact of environmental and other human behavioural factors on air quality is recommended by this study. On the Africa continent, only a few studies have looked at PM2.5 levels (Gaita et al 2014;Tshehla andDjolov 2018, Kalisa et al 2019) and elemental composition in an urban context region with a high population density, such as Pretoria and Cape town (Novela et al 2020;Williams et al 2020;Adeyemi et al 2021). As a result, the aim of this study was to determine the level of PM2.5 in the Pretoria region, as well as its elemental composition, during four different seasons: autumn, winter, spring, and summer.…”