Passive houses are ninety percent cleaner than standard homes

Most people assume that closing the windows during an air quality alert creates a sealed environment, but the reality of urban housing is far more porous. In a typical pre-war townhouse, air constantly migrates through window frames, under doors, and through tiny gaps caused by decades of structural settling. During major wildfire events, these leaks allow fine particulate matter to reach unhealthy levels indoors, offering residents surprisingly little protection from the hazardous conditions outside.