Wildfire-related PM2.5 and respiratory transmitted disease among Chinese children and adolescents from 2008 to 2019: A retrospective study.

Summary

Across 501 Chinese cities (2008–2019), each 5 μg/m3 increase in wildfire-related PM2.5 (lag 0–28 days) was associated with a 6.8% rise in daily incidence of respiratory transmitted diseases—far exceeding the 1.2% rise linked to non-wildfire PM2.5. Disease-specific increases were substantial for influenza (+28.6%), rubella (+12.6%), measles (+13.6%), and scarlet fever (+5.2%). Although wildfire PM2.5 represented only 2.7% of total PM2.5, it accounted for 10.8% of PM2.5-associated cases.

Key Findings

• Each 5 μg/m3 increase in wildfire PM2.5 (lag 0–28) increased daily respiratory infection incidence by 6.8% (95% CI 5.0–8.7%), versus 1.2% (1.0–1.4%) for non-wildfire PM2.5.
• Marked increases for specific infections: influenza +28.6%, rubella +12.6%, measles +13.6%, scarlet fever +5.2%.
• Wildfire PM2.5 comprised 2.7% of total PM2.5 but accounted for 10.8% of PM2.5-associated cases; in low-exposure areas, its share reached 29.7%.

Clinical Implications

Public health planning for wildfire seasons should incorporate respiratory infection mitigation (vaccination campaigns, air quality advisories, indoor filtration, school and activity guidance) and integrate wildfire PM2.5 into infectious disease surveillance models.

Limitations

• Potential exposure misclassification from city-average wildfire PM2.5.
• Residual confounding possible; mortality analyses limited by fewer events.

Future Directions

Integrate wildfire smoke metrics into infectious disease forecasting, evaluate interventions (filtration, sheltering, vaccination timing), and extend to adult and elderly populations with clinical severity endpoints.