South Africa's industrial zone has twice the safe air pollution levels
A year-long study of a residential area near Johannesburg found PM2.5 pollution at double the WHO safety threshold, exceeding guidelines on 13 days. The findings give air regulators critical data to update outdated pollution plans affecting millions of residents in Africa's most industrialized region.
Originaltitel: Ambient PM2.5 Concentrations, Chemical Composition and Source Characteristics in a Residential Area of the Industrial Highveld Priority Area, South Africa
Sustainable air quality governance requires robust monitoring and updated air quality management plans (AQMPs) to translate legislation into meaningful environmental and health protection. The Highveld Priority Area (HPA), which was declared South Africa’s second National Air Pollution Priority Area in 2007, includes the Ekurhuleni Metropolitan Municipality (EMM), where AQMPs are outdated and long-term chemical characterization data remain limited. This study provides baseline evidence to support AQMP revision by characterizing PM2.5 mass concentrations and chemical composition in a residential area of Kempton Park within the EMM and HPA. A total of 57 24 h PM2.5 samples were collected every sixth day from May 2021 to April 2022. Concentrations ranged from 0.9 to 32 µg/m3 (annual mean 10 µg/m3), exceeding the WHO annual guideline (5 µg/m3) but remaining below the South African standard (20 µg/m3). The daily WHO guideline (15 µg/m3) was exceeded on 13 days. PM2.5, black carbon and organic carbon peaked during winter and spring, consistent with enhanced atmospheric stability and combustion emissions, while elements Br, Fe, K, S, Si and Sr exhibited seasonal variability. Principal component analysis and enrichment factor assessment distinguished crustal sources (Si, Ca, Fe, Ti) from enriched anthropogenic elements (S, Zn, Br, U), indicating contributions from combustion, industrial activities and mining. Correlation patterns and 72 h back-trajectory analysis further demonstrated shared sources and significant regional transport influences. These findings highlight the combined role of local emissions, meteorology and long-range transport, providing locally relevant evidence to inform sustainable air quality management within the EMM and HPA.