Overview
This study applied the US EPA human health risk assessment (HRA) model to assess health risks from PM2.5 ambient air pollution and its trace elemental components in Thohoyandou, a rural South African community, using PM2.5 samples collected April 2017 to April 2018. Despite relatively moderate annual average PM2.5 of 11 µg/m3 (above WHO 10 µg/m3 guideline but below South African NAAQS of 20 µg/m3), health risks were substantial, especially for infants and children. Particle-bound nickel posed both non-cancer and cancer risks. The study concludes air quality standards in South Africa need to be tightened, as the risks were present even at levels compliant with national annual standards.
Key numbers
Annual average PM2.5: 11 µg/m3. WHO guideline: 10 µg/m3 annual mean; South African NAAQS: 20 µg/m3 annual mean, 40 µg/m3 24-hour mean. Adults exposed to PM2.5-related health risks during May-October (dry season); infants and children throughout the year. Nickel (particle-bound): posed non-cancer and cancer risks; specific HQ and CR values are in the source document. XRF analysis covers all elements between Al and U. LOD replacement: LoD/√2 for values below detection limit. Trace elements characterised by XRF; health risk assessment applied EPA reference doses derived from WHO guidelines, South African NAAQS, and US EPA reference concentrations.
Methods (brief)
PM2.5 sampled on filters every 3 days (24-hour) from April 2017 to April 2018 at 9 m above ground at University of Venda. Gravimetric mass determination. Chemical composition by XRF (XEPOS 5, SPECTRO Analytical). US EPA HRA model applied with reference doses from WHO, NAAQS, and EPA.
Implications
Certification: air pathway metal exposure context; nickel in PM2.5 is relevant to background inhalation exposure, which contributes to total body burden alongside dietary intake. Not a food-matrix study.
Courses: useful for illustrating inhalation pathway health risk assessment methodology and the special vulnerability of infants and children to air pollution.
App: not applicable to food-matrix contamination profiles.
Wiki pages updated on ingest
Update history
The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.
| Commit | Date | Change | Description |
|---|---|---|---|
| a8052bb | 2026-08-09 | major | 6 sections added; narrative text revised |