Sequencing mobile environmental exposure and travel stress in Singapore

Cities can supply greenery widely while making it unevenly available to people moving through them. We argue that mobility helps constitute exposure: it organizes how greenness, crowding, and noise combine within a moment, how environmental supply becomes perceptible under movement, and how moments are ordered across the day. We examined this process in Singapore through 21 days of geographic ecological momentary assessment (GEMA) with 57 participants, linking momentary reports of stress, perceived greenness, and crowding to satellite-derived greenness and watch-recorded noise at each GPS location, yielding 5963 moments across 1225 participant-days, alongside 25 follow-up interviews. Momentary stress was higher when crowding occurred alone or with greenness deficit, and higher still where deficit, crowding, and elevated noise coincided. Objective greenness was more strongly associated with perceived greenness en-route than post-arrival, and under active than motorized travel. Longer consecutive stretches within the same combination of conditions were associated with lower daily stress, beyond what the day contained. Interviews traced these patterns to the work of travel: transfers, timing, and weather decided what journeys required and what surroundings could be noticed. Configuration, translation, and sequence therefore recast mobile exposure as environmental supply reorganized by movement. Where greenery is already extensive, the remaining levers lie partly with the systems that organize movement.