Background <p>The relationship between transportation noise and health-related quality of life (HRQoL) has been established, but its specific effects on residents of multi-story buildings, who are also exposed to neighbour noise, require further investigation.</p> Objective <p>This study sought to investigate the effects of transportation noise on HRQoL among adults residing in such buildings.</p> Methods <p>A cross-sectional study was conducted with 400 participants recruited from four apartment complexes. Transportation noise was measured over a 24-h period, and the resulting data were used to create noise maps. HRQoL was assessed using the RAND-36, which measures physical (PCS) and mental (MCS) component summaries.</p> Results <p>The results revealed significant negative associations between outdoor noise exposure (overall, road traffic, and railway) and both PCS and MCS, with road traffic noise showing the strongest effects. Noise sensitivity, indoor acoustic satisfaction, and outdoor noise annoyance were identified as significant effect modifiers, with higher sensitivity and annoyance levels exacerbating the negative impacts of noise on HRQoL.</p> <p></p> Impact statement <p><UnorderedList Mark="Bullet"> <ItemContent> <p>This study contributes to the growing body of evidence on the health effects of noise pollution by addressing several underexplored aspects. First, it examines the differential impacts of road traffic and railway noise on HRQoL, providing insights into the relative contributions of these noise sources. Second, it investigates the role of noise sensitivity and indoor acoustic satisfaction as potential modifiers of noise-related health outcomes, offering valuable information for targeted interventions. Finally, the study’s focus on urban apartment residents highlights the unique challenges faced by this population, informing policies and building design strategies aimed at improving residential environments and public health.</p> </ItemContent> </UnorderedList></p>