Comparative assessment of PM₂.₅ and carcinogenic trace elements across four South African sampling sites
1
School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
2
Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
3
Department of Occupational and Environmental Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, University of Gothenburg, Sweden
Popul. Med. 2026;8(Supplement Supplement 1):
ABSTRACT
BACKGROUND:
Fine particulate matter (PM₂.₅) is a major contributor to global disease burden, yet long-term monitoring and chemical characterisation remain limited in low- and middle-income countries, including South Africa. While PM₂.₅ mass concentrations are routinely reported, less is known about PM₂.₅-bound carcinogenic trace metals and their associated health risks in African settings. These metals can penetrate deep into the respiratory system and induce oxidative stress, inflammation and cancer, underscoring the need for site-specific exposure and risk assessments. The aim was to compare PM₂.₅ concentrations and carcinogenic trace element risks across four South African sites (Pretoria, Thohoyandou, Mabopane and Bloemfontein).
METHODS:
24-hour PM₂.₅ samples were collected at regular intervals, analysed gravimetrically and chemically characterised using energy-dispersive X-ray fluorescence. Health risks were estimated following the U.S. EPA Human Health Risk Assessment framework, with lifetime excess cancer risks calculated for arsenic (As), nickel (Ni) and hexavalent chromium (Cr(VI)). The World Health Organization (WHO) annual PM₂.₅ guideline of 5 µg/m³ was used as a reference.
RESULTS:
Mean PM₂.₅ concentrations exceeded the WHO annual guideline at all sites, with the highest levels observed in Pretoria (23.2 µg/m³), followed by Thohoyandou (11.0 µg/m³), Bloemfontein (11.0 µg/m³) and Mabopane (10.0 µg/m³). Ni was the most consistent contributor to cancer risk across sites, with lifetime excess cancer risks exceeding commonly accepted benchmarks. As contributed additional seasonal risk in Pretoria, while Cr(VI) dominated cancer risk in Bloemfontein.
CONCLUSIONS:
PM₂.₅ pollution in South Africa remains well above the WHO guideline, with carcinogenic trace metals contributing substantially to health risks. Concentrations were consistently elevated during cold and dry seasons, reflecting increased domestic fuel combustion and reduced atmospheric dispersion. Ni sources may include traffic, industrial activities and combustion sources. Expanded chemical speciation monitoring and targeted emission control strategies are needed to reduce exposure, particularly in vulnerable communities and high-risk environments.
Fine particulate matter (PM₂.₅) is a major contributor to global disease burden, yet long-term monitoring and chemical characterisation remain limited in low- and middle-income countries, including South Africa. While PM₂.₅ mass concentrations are routinely reported, less is known about PM₂.₅-bound carcinogenic trace metals and their associated health risks in African settings. These metals can penetrate deep into the respiratory system and induce oxidative stress, inflammation and cancer, underscoring the need for site-specific exposure and risk assessments. The aim was to compare PM₂.₅ concentrations and carcinogenic trace element risks across four South African sites (Pretoria, Thohoyandou, Mabopane and Bloemfontein).
METHODS:
24-hour PM₂.₅ samples were collected at regular intervals, analysed gravimetrically and chemically characterised using energy-dispersive X-ray fluorescence. Health risks were estimated following the U.S. EPA Human Health Risk Assessment framework, with lifetime excess cancer risks calculated for arsenic (As), nickel (Ni) and hexavalent chromium (Cr(VI)). The World Health Organization (WHO) annual PM₂.₅ guideline of 5 µg/m³ was used as a reference.
RESULTS:
Mean PM₂.₅ concentrations exceeded the WHO annual guideline at all sites, with the highest levels observed in Pretoria (23.2 µg/m³), followed by Thohoyandou (11.0 µg/m³), Bloemfontein (11.0 µg/m³) and Mabopane (10.0 µg/m³). Ni was the most consistent contributor to cancer risk across sites, with lifetime excess cancer risks exceeding commonly accepted benchmarks. As contributed additional seasonal risk in Pretoria, while Cr(VI) dominated cancer risk in Bloemfontein.
CONCLUSIONS:
PM₂.₅ pollution in South Africa remains well above the WHO guideline, with carcinogenic trace metals contributing substantially to health risks. Concentrations were consistently elevated during cold and dry seasons, reflecting increased domestic fuel combustion and reduced atmospheric dispersion. Ni sources may include traffic, industrial activities and combustion sources. Expanded chemical speciation monitoring and targeted emission control strategies are needed to reduce exposure, particularly in vulnerable communities and high-risk environments.
| eISSN: | 2654-1459 |
We process personal data collected when visiting the website. The function of obtaining information about users and their behavior is carried out by voluntarily entered information in forms and saving cookies in end devices. Data, including cookies, are used to provide services, improve the user experience and to analyze the traffic in accordance with the Privacy policy. Data are also collected and processed by Google Analytics tool (more).
You can change cookies settings in your browser. Restricted use of cookies in the browser configuration may affect some functionalities of the website.
You can change cookies settings in your browser. Restricted use of cookies in the browser configuration may affect some functionalities of the website.
