Daily mortality records from 1366 communities in ten countries and territories over 2000-19 were linked to modelled landscape fire PM2·5, using instrumental variable models alongside conventional time-series estimates. Each 1 µg/m³ rise in the 2-day mean of landscape fire PM2·5 was associated with a 0·60% (95% CI 0·19-1·00) increase in mortality, giving 906 869 attributable deaths, or 1·90% of the total. Landscape fire smoke was 19·0% of ambient PM2·5 mass but 30·6% of PM2·5-attributable deaths.
Why it is interesting: The instrumental-variable approach raises the attributable burden by more than half over conventional estimates, bearing directly on how smoke mortality is attributed.