Ambient PM₂.₅ air pollution in Botswana: Composition, source apportionment, and implications for air pollution policy
1
Environmental Health, University of Botswana, Gaborone, Botswana
2
University of Pretoria, Pretoria, South Africa
Popul. Med. 2026;8(Supplement Supplement 1):
ABSTRACT
BACKGROUND:
Fine particulate matter (PM₂.₅) is a major environmental health concern due to its ability to penetrate deep into the respiratory system and enter the bloodstream, causing significant morbidity and mortality. In Sub-Saharan Africa, ambient PM₂.₅ concentrations remain among the highest globally, yet monitoring infrastructure and epidemiological evidence are limited. In Botswana, available studies indicate that urban centres such as Gaborone frequently exceed the World Health Organization (WHO) annual guideline of 5 µg/m³. PM₂.₅ pollution in Botswana is influenced by local sources such as vehicular emissions, biomass burning, and windblown dust, as well as transboundary transport from neighbouring countries. However, existing studies are sporadic, short-term, and insufficient for comprehensive exposure and health risk assessment.
METHODS:
This review synthesizes published studies on PM₂.₅ concentrations, chemical composition, source apportionment, meteorological influences, and health impacts relevant to Botswana. Measurement approaches assessed include gravimetric sampling, regulatory-grade continuous monitors, low-cost sensors, and satellite-derived aerosol optical depth products. Studies on apportionment methods such as Positive Matrix Factorization and trajectory analysis using HYSPLIT were reviewed. Studies evaluating health impacts using both epidemiological evidence and hazard-based health risk assessment frameworks applicable to data-limited settings were included.
RESULTS:
Available evidence shows that PM₂.₅ concentrations in Gaborone commonly exceed WHO guidelines, with pronounced diurnal and seasonal variability. Winter time temperature inversions and biomass burning episodes result in elevated concentrations. Chemical analyses reveal a mixture dominated by crustal dust, black carbon, organic carbon, and trace metals. Limited source apportionment studies identify vehicular emissions, biomass burning, and resuspended dust as major contributors.
CONCLUSIONS:
PM₂.₅, poses a significant but under-characterized environmental health risk in Botswana. Establishing continuous monitoring networks, integrating low-cost sensors and applying source apportionment models are critical for evidence-based policy. Strengthened air quality management will support public health protection and sustainable development goals in Botswana.
Fine particulate matter (PM₂.₅) is a major environmental health concern due to its ability to penetrate deep into the respiratory system and enter the bloodstream, causing significant morbidity and mortality. In Sub-Saharan Africa, ambient PM₂.₅ concentrations remain among the highest globally, yet monitoring infrastructure and epidemiological evidence are limited. In Botswana, available studies indicate that urban centres such as Gaborone frequently exceed the World Health Organization (WHO) annual guideline of 5 µg/m³. PM₂.₅ pollution in Botswana is influenced by local sources such as vehicular emissions, biomass burning, and windblown dust, as well as transboundary transport from neighbouring countries. However, existing studies are sporadic, short-term, and insufficient for comprehensive exposure and health risk assessment.
METHODS:
This review synthesizes published studies on PM₂.₅ concentrations, chemical composition, source apportionment, meteorological influences, and health impacts relevant to Botswana. Measurement approaches assessed include gravimetric sampling, regulatory-grade continuous monitors, low-cost sensors, and satellite-derived aerosol optical depth products. Studies on apportionment methods such as Positive Matrix Factorization and trajectory analysis using HYSPLIT were reviewed. Studies evaluating health impacts using both epidemiological evidence and hazard-based health risk assessment frameworks applicable to data-limited settings were included.
RESULTS:
Available evidence shows that PM₂.₅ concentrations in Gaborone commonly exceed WHO guidelines, with pronounced diurnal and seasonal variability. Winter time temperature inversions and biomass burning episodes result in elevated concentrations. Chemical analyses reveal a mixture dominated by crustal dust, black carbon, organic carbon, and trace metals. Limited source apportionment studies identify vehicular emissions, biomass burning, and resuspended dust as major contributors.
CONCLUSIONS:
PM₂.₅, poses a significant but under-characterized environmental health risk in Botswana. Establishing continuous monitoring networks, integrating low-cost sensors and applying source apportionment models are critical for evidence-based policy. Strengthened air quality management will support public health protection and sustainable development goals in Botswana.
| eISSN: | 2654-1459 |
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