Indoor Thermal Vulnerability and Climate Justice: Understanding Adaptation Barriers in a Low-Income Lisbon Neighbourhood

Despite its mild winters, Portugal experiences the highest number of winter-related injuries and deaths. This suggests that inadequate housing and insufficient adaptive measures are major contributors to excess mortality.  

A 2021 study on elderly vulnerability to summer temperatures in Lisbon highlighted structural and behavioural limitations to adaptive capacity. However, the relationship between indoor thermal environments and human health in disadvantaged communities remains underexplored.  

This observational study was conducted in a low-income, informally constructed neighbourhood where residents face poverty and significant health challenges. During winter, meteorological data were collected from six households, monitoring thermal conditions in the most frequently used spaces: the bedroom and living room. Biometeorological indices, such as the Universal Thermal Climate Index (UTCI) and Predicted Mean Vote (PMV), were used to assess cold exposure, and face-to-face interviews provided further insight into living conditions.  

The results revealed severe indoor cold exposure, with a significant portion of monitored hours falling below thermal comfort guidelines, particularly at night. Indoor temperatures frequently dropped to levels that worsened respiratory issues, joint pain, and mobility difficulties. Although most households owned heating devices, high energy costs meant they were only used on cold days. Instead, residents resorted to inadequate measures such as blankets or going to bed early to escape the cold.  

Health impacts were evident, with residents reporting aggravated bone pain, throat irritation, sleep disturbances, and respiratory illnesses linked to high humidity and mould exposure. Additionally, a lack of knowledge on indoor thermal adaptation was observed, highlighting the need for greater community education and awareness initiatives.  

This study provides critical insights into the barriers to thermal adaptation in vulnerable communities. It reinforces the urgent need for equitable housing policies and climate justice-driven interventions to improve living conditions and access to affordable energy.