Towards healthy buildings: developing harm-metric frameworks to support design and decision-making

Current Indoor Air Quality (IAQ) regulations rely on concentration thresholds for individual pollutants, which limits their ability to capture cumulative health impacts and hinders the development of performance-based ventilation standards. Building on prior work, including Annexe D of ASHRAE 62.2, this study introduces a harm-based framework that shifts the reference from indoor concentrations to a standardised emission rate scenario. The proposed Harm Metric aggregates multiple contaminant exposures into a single health outcome expressed in DALYs·(105 pers)−1·year−1, enabling an outcome-based evaluation of ventilation performance.Applied to a representative sample of the French dwelling stock, the metric shows a median total harm of 994 DALYs·(105 pers)−1·year−1. The main contributors are particulate matter, formaldehyde, nitrogen dioxide (NO2), and radon. A ventilation sensitivity analysis demonstrates the metric’s responsiveness, with total harm decreasing to around 800 DALYs·(105 pers)−1·year−1 when airflow exceeds 350 m³·h−1 in a 100 m2 dwelling.By linking emissions, ventilation, and health outcomes, this framework supports integrating chronic exposure impacts into building standards and codes. It offers policymakers a quantitative basis for transitioning towards performance-based regulation and highlights the need for improved emission scenarios using large-scale real-world data.