Socioeconomic and racial disparities in thermal comfort conditions in Brazil

The role of environmental disparities in exposure to ambient temperature and its impact on health, focusing solely on temperature exposure may not fully capture the complexity of thermal stress experienced by individuals. Thermal comfort conditions, encompassing factors such as humidity and wind speed alongside temperature, provide a more complete understanding of human comfort and well-being. In this study, we investigated the socioeconomic and racial disparities in thermal comfort conditions across Brazil. We conducted an ecological analysis at the census-tract (sub-municipal) scale across Brazil (n = 34,016 tracts). Thermal comfort indices (Discomfort Index, Humidex, Heat Index, Net Effective Temperature) were computed from ERA5-Land meteorology at 0.1° (∼10 km) and linked to tracts via centroid-within-grid–cell assignment. We employed a Generalized Additive Models (GAMs) adjusted for socioeconomic status (SES), race/ethnicity, and geographic factors to assess the associations between these variables and thermal comfort indices. Our findings suggest that lower SES indicators, such as income and education, are associated with higher exposure to thermal stress, indicating significant discomfort conditions with potential health implications. We also observed nuanced associations across different racial/ethnic groups, with variations in exposure levels at different percentiles. Our results suggest that the disparities in thermal comfort conditions persist across urban and rural areas, highlighting the pervasive nature of these inequalities. These findings underscore the need for targeted interventions and policy initiatives aimed at addressing environmental justice and promoting health equity in Brazil.