Exposure to built and social environments and momentary well-being: A geographic ecological momentary assessment study in Montreal

• Momentary well-being is higher among older adults. • Afternoon and weekend days significantly boost momentary well-being levels. • Temperature shows a marginal positive association with momentary well-being. • Social interactions with friends and family enhance momentary well-being. • Women report lower well-being than men when alone among others. Understanding how built and social environments shape momentary well-being is essential for advancing urban health research and planning. This study investigated temporal, social, and environmental predictors of daily well-being using a geographic ecological momentary assessment (GEMA) approach. Seven-day GEMA measures were collected between 2018 and 2021 among 889 residents of Greater Montreal, recruited through the INTERACT and REM studies. Participants (mean age = 41.7 years; age range = 18–80 years; 55.7% women) completed the Short Mood Scale three times daily via the EthicaData smartphone app, yielding over 10,600 prompts linked with GPS data. Multilevel mixed-effects models were used to assess the associations between well-being and temporal, social, and environmental exposures. Well-being varied significantly across time and contexts (conditional R 2 ≈ 0.6). Higher well-being was reported in the afternoon (β = 0.23, 95% CI: 0.03–0.43) and on weekends, particularly Sundays (β = 1.11, 95% CI: 0.74–1.49), whereas evenings were associated with lower well-being (β = –0.31, 95% CI: –0.52 to –0.10). Social interactions, especially with friends (β = 1.97, 95% CI: 1.26–2.67) and family (β = 0.83, 95% CI: 0.42–1.25), were strongly associated with higher well-being. Built environment features, including greenness, proximity to parks, and road density, showed limited associations. Older adults (60–80 years) reported substantially higher well-being than younger (18–40) adults (β = 4.31, 95% CI: 3.44–5.18). An interaction indicated that women reported lower well-being than men when surrounded by others without direct interaction (β = –0.66, 95% CI: –1.17 to –0.09). Temporal rhythms, age, and social interactions were central determinants of momentary well-being, while built environment factors played a lesser role. Integrating GEMA approaches provides robust evidence to inform urban planning and public health strategies that promote supportive social and temporal environments.