National transitions in childhood lower respiratory infection burden attributable to household versus ambient particulate matter pollution, 1990–2023: Timing, persistence, and uncertainty in GBD 2023

Global estimates indicate that the combined childhood lower respiratory infection burden attributable to household and ambient particulate matter pollution fell sharply from 1990 to 2023, while the relative balance between the two components shifted toward ambient pollution in more countries. A GBD 2023 analysis examined children younger than five in 204 countries and territories, assessing not only the start and end of the period but also the timing, persistence and uncertainty of national transitions. Across the study population, lower respiratory infection deaths attributable to the two pollution components declined from an estimated 731,498 in 1990 to 212,667 in 2023. The corresponding estimated death rate fell from 119.08 to 33.07 per 100,000 children under five.

The study used Global Burden of Disease Study 2023 parent-risk estimates to quantify pollution-attributable burden. It separated the burden attributed to household air pollution from solid fuels and ambient particulate matter pollution, then defined dominance as the larger attributable-burden component rather than as a direct measurement of emissions contributions. Based on death-rate point estimates, ambient particulate matter pollution exceeded household air pollution as the larger attributable component in 99 countries in 1990 and in 134 in 2023. The researchers characterized this changing balance with a transition index: the natural logarithm of the ratio of the ambient-pollution-attributable rate to the household-pollution-attributable rate. The results therefore describe a model-based shift in disease burden attributed to the two risk components, not observed changes in the relative volume of pollution emitted from household and ambient sources.

The apparent timing of national transitions depended on the confirmation rule used. Requiring a transition to persist for two years identified 35 follow-up transitions, with a median transition year of 2005. Three-year confirmation produced 36 transitions, also with a median year of 2005, while five-year confirmation identified 35 transitions with a median year of 2004. These largely similar counts and dates show that the analysis did not assign a single worldwide transition date; instead, it assessed individual national trajectories under alternative criteria for continued persistence. The framework also characterized whether transitions were uninterrupted and whether reversals occurred, adding information that cannot be obtained by comparing only the burden in 1990 and 2023.

Death-based and disability-adjusted life-year-based classifications were closely aligned under the three-year rule. The two outcome measures produced the same national transition status in all 204 countries and territories, and their transition years matched in all 36 jointly identified transitions. Agreement between these metrics supports the internal consistency of the observed component shift within the model, although it does not eliminate uncertainty in the underlying burden estimates. In particular, the 95% uncertainty intervals for the ambient and household pollution components overlapped in 67 locations, representing 32.84% of the study population. In nearly one third of locations, therefore, the available point estimates did not provide a clean statistical separation between the two components.

Together, the findings offer a more detailed picture of change in childhood lower respiratory infection burden than endpoint rankings alone. The estimated total burden declined markedly across the 204 countries and territories, while ambient particulate matter pollution became the larger attributable component in more places. At the same time, the timing of relative transitions varied nationally, and overlapping uncertainty intervals limited confident classification in a substantial minority of locations. The analysis does not establish that ambient pollution caused the decline in total deaths, nor does it convert attributable disease burden into a direct inventory of source emissions. Its contribution is instead a model-based national description of when the relative balance changed, how long transitions persisted, where reversals were observed, and how uncertainty complicates those classifications.

Subject of Research: GBD 2023 analysis of national shifts in childhood lower respiratory infection burden attributed to household and ambient particulate matter pollution

Article Title: National transitions in childhood lower respiratory infection burden attributable to household versus ambient particulate matter pollution, 1990–2023: Timing, persistence, and uncertainty in GBD 2023

Article References: Du, Q., Qin, C., Tian, Z., He, Z., Han, N., Wang, Y., Kong, L., Hu, H., Sun, M., & Zhang, Y. (2026). National transitions in childhood lower respiratory infection burden attributable to household versus ambient particulate matter pollution, 1990–2023: Timing, persistence, and uncertainty in GBD 2023. Air Quality, Atmosphere & Health, 19(11), Article 242. https://doi.org/10.1007/s11869-026-02129-8

Image Credits: AI Generated

DOI: 10.1007/s11869-026-02129-8

Keywords: GBD 2023, childhood lower respiratory infections, ambient particulate matter, household air pollution, under-five mortality, global burden of disease, national transitions, uncertainty intervals, pollution-attributable burden, disability-adjusted life years, National, transitions