Abstract
BACKGROUND: Particulate matter pollution (PMP) remains a leading risk factor for lower respiratory infections (LRIs) globally. However, the evolving contributions of household air pollution (HAP) versus ambient particulate matter pollution (APMP) across different development stages remain poorly characterized, hindering targeted intervention strategies. METHODS: Using Global Burden of Disease 2021 data from 204 countries (1990-2021), we analyzed age-standardized mortality rates (ASMR) and disability-adjusted life years (DALY) for PMP-attributable LRIs, stratified by Socio-demographic Index (SDI), pollution source, and demographics. Temporal trends were assessed using Joinpoint regression, with projections to 2050. RESULTS: In 2021, PMP was responsible for an estimated 651,238 (95% UI, 121,605-1076,503) deaths and 29,098,331(6,988,265-48,127,683) DALY from LRIs globally (ASMR: 8.68; ASDR: 420.09 per 100,000). Despite significant declines since 1990 (ASMR EAPC: -2.44%), profound disparities persisted. Low-SDI regions experienced 23-fold higher mortality (ASMR: 31.28 per 100,000) than high-SDI regions (ASMR: 1.34 per 100,000), with slower improvement rates (EAPC: -3.41% vs -6.76% in high-middle SDI). A critical epidemiological transition emerged: APMP became predominant in high-income regions (approaching 100% of PMP burden), while HAP dominated in low-SDI settings (ASMR: 26.12 per 100,000). Regional heterogeneity was marked, with Central Sub-Saharan Africa bearing the highest HAP burden and minimal APMP improvement (EAPC: -0.24%). Children under 5 years of age group still accounted for the most PMP-related deaths, with the number decreasing from 851,458 (95% UI: 211,026 to 1,363,810) in 1990 to 201,078 (95% UI:61,817 to 337,232). In contrast, the APMP-related burden increased among adults aged 20 years and older. Strong inverse correlations between SDI and disease burden (r=-0.85, p<0.001) confirmed socioeconomic determinants. Projections suggest decelerating improvements post-2030. CONCLUSION: The global PMP reduction masks widening inequities between regions at different development stages. The divergent pollution profiles-HAP persistence in low-SDI regions versus APMP dominance in high-SDI regions-necessitate differentiated intervention strategies addressing both household energy transitions and ambient air quality regulations to achieve health equity by 2050.