A Time-and Site-Specific Questionnaire-Based Method for Estimating Outdoor Daylight Exposure in Built Environment Field Studies
Frontiers in Built Environment, cilt.12, sa.1, ss.1-32, 2026 (ESCI, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 12 Sayı: 1
- Basım Tarihi: 2026
- Doi Numarası: 10.3389/fbuil.2026.1888375
- Dergi Adı: Frontiers in Built Environment
- Derginin Tarandığı İndeksler: Scopus, Emerging Sources Citation Index (ESCI)
- Sayfa Sayıları: ss.1-32
- Dokuz Eylül Üniversitesi Adresli: Evet
Özet
Outdoor daylight exposure can provide useful context for built environment field studies, but practical assessment is difficult. Wearable sensors provide detailed data but require equipment, calibration, data processing and participant compliance. Questionnaires are easier to administer, yet duration-only questions treat all outdoor minutes as equal, although available daylight varies by time, place and season. This study developed a questionnaire-based method for estimating outdoor daylight exposure and compared two estimates derived from the same self-report grid. The method was applied to a university library dataset collected at the UCL Bartlett Library in London, comprising 193 cleaned participant records. Participants reported outdoor periods, defined as being outside without a roof above the head, in 15-minute intervals between 07:00 and 16:00 for regular workdays and free days during the previous four weeks. The first estimate calculated total outdoor duration in minutes/day. The second combined the reported intervals with interval-specific daylight availability weights from a representative late-autumn weather profile for London St James's Park, producing a time- and irradiance-weighted estimate in lux·hour/day. Among the 179 participants in the main method-comparison sample, the estimates were strongly associated (Pearson r = 0.913; Spearman ρ = 0.870; R² = 0.833). However, 16.7% of the variance in the weighted estimate was not explained by duration alone, and 45 participants (25.1%) were assigned to a different low-, medium- or high-exposure group when timing and site-specific daylight availability were included. The weighted estimate remained closely related to duration-only reporting, while producing different exposure classifications for one-quarter of participants. It should therefore be treated as an optional, fit-for-purpose, macro-scale contextual proxy when exposure timing or broad site- or season-specific daylight context is analytically important. Duration-only reporting may remain adequate when overall time outdoors is the primary construct. These findings do not establish that the weighted estimate is more accurate or predictive; validation against participant-worn light measurements is required before claims of accuracy or superiority can be made.