Conforto térmico em áreas de intensa atividade comercial: Variabilidade espacial da temperatura e seus impactos para população

Abstract

This study investigates the interplay between thermal comfort and air quality in commercial areas of São Luís, Paço do Lumiar, and São José de Ribamar (MA), focusing on the neighborhoods of João Paulo, Cohab, Cidade Operária, and Estrada de Ribamar. Data were collected through mobile transects and fixed sensors, including thermo-hygrometers for temperature and relative humidity measurements, PM2.5 monitoring, and structured questionnaires administered to area users during the dry (2024) and rainy (2025) seasons. Spatial analysis using IDW interpolation in QGIS revealed persistent urban heat islands regardless of season, along with minor thermal fluctuations between weekdays and weekends, highlighting the influence of urban land use on local microclimates. Thermal comfort indices, namely the Heat Index (HI) and Effective Temperature (TE), indicated recurrent health risks, with “Danger” and “Extreme Danger” levels predominating in João Paulo and Cohab, while Cidade Operária and Maiobão exhibited comparatively lower values. Users’ subjective thermal perception aligned with these metrics, reporting discomfort and symptoms such as headaches, fatigue, and dizziness. PM2.5 concentrations exhibited clear seasonal variability, peaking above 20 μg/m3 during the dry season and decreasing in the rainy season. Statistical analyses revealed a negative correlation with relative humidity and weak associations with precipitation, wind, and temperature. The Distributed Lag Nonlinear Model (DLNM) showed that PM2.5 exerted a significant effect only at elevated exposure levels (>20 μg/m3), with a lag of approximately 10 days, corresponding to an estimated 150% increase in the relative risk of respiratory hospitalizations. Stepwise multiple regression identified relative humidity (p = 0.000337) and wind speed (p = 0.00177) as the most explanatory factors, although the low R2 highlights the multifactorial nature of hospitalizations. These findings underscore the critical influence of urban climate and air quality on public health and emphasize the need for integrated urban planning strategies, including thermal comfort mitigation, expansion of green infrastructure, redesign of urban furniture, and regulation of vehicular emissions, to foster healthier, more resilient, and socially equitable commercial environments.