Thermal Failure and Respiratory Health: A Physics-Based Exposure Metric and the Socioeconomic Moderation of Housing-COPD Associations in Greater Manchester

This Research Note introduces Weighted Failure Hours—a physics-based thermal exposure metric—and estimates its association with emergency respiratory hos- pitalisations across 294 neighbourhoods in Greater Manchester. Weighted Failure Hours integrates dwelling-level heat loss coefficients, household income-based affordability constraints, and observed weather data to estimate the annual hours during which affordable heating is insufficient to maintain indoor temperatures above the WHO safety threshold of 12◦C. Utilizing a log-log specification with controls for outdoor air pollution (PM2.5, NO2) and barriers to healthcare, we test whether thermal failure exposure operates as an independent driver of COPD admissions after spatial correction. After applying Eigenvector Spatial Filtering (ESF) to correct for spatial autocorrelation, a significant independent association is identified in wealthier neighbourhoods (N = 143; βESF = 0.176, p = 0.023) but not in the most deprived areas (N = 151; βESF = 0.028, p = 0.110). A con- founder step-through analysis reveals that barriers to healthcare services absorb the thermal failure signal in deprived areas, suggesting that healthcare access is the binding constraint on emergency COPD admissions in the most deprived neighbourhoods. ESF stability diagnostics confirm the wealthy-area coefficient is not an artefact of eigenvector overfitting. These findings are consistent with thermal failure representing a direct respiratory health stressor in areas where healthcare access is not the primary limiting factor, and are robust to a placebo outcome test using hip fracture admissions. JEL Classification: I14 , I18 , C21 , R20