Wildfires and heatwaves are driving an increase in toxic fine particulate pollution, the World Meteorological Organization (WMO) warned, in a finding with immediate implications for public health and air quality management in South Africa and beyond.
Global trend threatens local gains
The WMO’s latest annual Air Quality and Climate Bulletin stresses that while emissions from industry and transport have declined in some regions, exposure to fire-related PM2.5 — microscopic particles smaller than 2.5 micrometres in diameter — has risen where extreme fires have become more frequent and intense. PM2.5 can penetrate deep into the lungs and enter the bloodstream, increasing risks of respiratory, cardiovascular and other health problems.
"Extreme wildfires are increasing, leading to big health consequences because of the high toxicity of smoke," the WMO said in a statement accompanying the bulletin.
The bulletin links this trend to climate change, which scientists say is driving more frequent and severe heatwaves and wildfires. It calls for better monitoring of airborne pollutants — including aerosols such as black carbon and microplastics, fine particles and ground-level ozone — noting many of these substances remain inadequately measured despite being widespread and harmful to ecosystems and human health.
Why wildfire smoke is a particular concern
The WMO emphasises that particles from burning vegetation can be more toxic than particles from other sources, including vehicle exhaust. Lorenzo Labrador from the WMO’s Global Atmosphere Watch network told AFP that in regions with major forest fires, "we find a lot of fine particle pollution" and that microparticles from vegetation burning are "much more toxic" than some other sources.
- PM2.5 sources: fossil-fuel combustion, farming, domestic heating, transport, wildfires and dust storms.
- Insufficient monitoring: black carbon, microplastics, fine particles and ground-level ozone are not consistently tracked in many areas.
- Policy need: the WMO calls for coordinated air quality and climate policies because the two issues are interlinked.
The report underlines that declines in industrial and transport PM2.5 in some high-income regions can be offset by increasing exposure to fire-related particles, which can travel long distances and affect populations far from the source of the blaze.
Implications for South African health services and the public
South Africa already contends with seasonal veld fires and heatwaves in various provinces. The WMO’s assessment signals a need for health services, environmental agencies and municipal planners to factor wildfire smoke into air-quality alerts, public health advisories and emergency response plans.
Practical measures for clinicians and the public include:
- recognising symptoms linked to PM2.5 exposure — worsening asthma, coughing, chest pain, shortness of breath — and advising at-risk patients to seek clinical care;
- strengthening air-quality monitoring and public warning systems to give early notice of smoke events;
- adopting coordinated policies that address both climate mitigation and air-pollution reduction to avoid one policy undermining the other.
Health professionals should continue to guide patients to clinics or emergency care rather than encouraging self-diagnosis. Those with chronic respiratory or cardiac conditions, young children, older adults and pregnant people are typically most vulnerable to PM2.5 exposure and should follow medical advice during smoke events.
| Pollutant | Health/ecosystem concern |
|---|---|
| PM2.5 (fine particles) | Respiratory and cardiovascular disease; travels long distances |
| Black carbon | Climate warming agent; impacts air quality and health |
| Ground-level ozone | Respiratory irritation; damages crops and ecosystems |
The WMO recommends enhanced monitoring networks and integrated policy responses because air quality and climate change are mutually reinforcing problems: if one deteriorates, the other is likely to worsen. Improved measurement of aerosols and particulate composition, including emerging concerns such as microplastic particles in the air, will be critical to assessing risk and directing public-health interventions.
Officials and clinicians should note the bulletin’s central message: tackling air pollution and climate change together offers the best chance to protect health, ecosystems and long-term air quality. Individuals experiencing symptoms after smoke exposure are urged to consult a healthcare provider for assessment and treatment.
