Exploring climate, air pollution, and respiratory disease hospitalizations in Brazil: a scoping review.

INTRODUCTION: Air pollution is the leading environmental risk factor for mortality worldwide, contributing to 7.9 million deaths in 2023. In Brazil, studies evaluating the combined relationship between air pollution, climate variables, and respiratory disease hospitalizations remain fragmented and regionally concentrated. AREAS COVERED: This scoping review mapped the Brazilian literature on air pollution, climate, and respiratory hospitalizations across multiple scientific databases. A total of 1,179 studies were identified, of which 129 met the eligibility criteria after screening and full-text assessment. Respiratory infections, including pneumonia and COVID-19, followed by asthma, were the most frequently investigated outcomes, with children representing the main target population. The review also revealed geographical asymmetry, as a single federative unit concentrated more than one-third of all published studies. Overall, 117 studies (90.70%) reported positive associations between environmental exposures and hospitalizations, of which 112 reported significant results. EXPERT OPINION: Environmental epidemiology in Brazil remains limited by methodological fragmentation, territorial inequalities, and insufficient local coverage, with only 42 municipalities (0.75% of the Brazilian municipalities) individually identified among municipal-scale studies. Although the literature establishes an important epidemiological baseline, substantial structural gaps still hinder advances in the field, reinforcing the urgent need for decentralized research strategies, methodological modernization, and integrated climate-health approaches.