本研究以三軸加速規測量每日步行數 ，並透過生態瞬時評估（ecologically momentary assessment）測量每日戶外情境，進而探討每日步行數與特定的戶外情境對於每日情感的影響。共154位成年人參與本研究，研究對象連續7日在早上、下午、晚上會隨機收到提醒訊號以回答當下的戶外情境與當下的情感程度；此外，每位研究對象皆配戴三軸加速規（activPAL）連續7日以測量每日步行數。透過階層線性模型分析後發現，當成年人當日步行數越高時，以及當日步行於自然場域與步道越頻繁時，在當日有越高程度的正向情感。對於成年人心理健康而言，若提升個人在自然場域的日常步行頻率，有助於促進心理健康。本研究提供學術單位在未來的研究方向，並提供公共衛生政府部門在未來推廣步行時的參考依據。

This study aimed to examine the unique effects of specific outdoor contexts and accelerometry-assessed daily steps on daily affect using ecological momentary assessments (EMA). A total of 154 adults completed randomly delivered EMA surveys three times per day for seven days on their smartphones. During each EMA survey, they indicated their current context and rated its positive affect on themselves. They also wore an activPAL accelerometer to record their daily steps during the study period. Multilevel modeling was used to investigate the day-level associations between daily steps, specific outdoor contexts, and daily affect. Our multilevel models suggest that participants with higher numbers of daily steps and greater exposure to natural or green spaces, walking trails, or pathways on a given day experienced a higher degree of positive daily affects. Our EMA study indicates that this contextual benefit may be independent of higher activity levels (assessed by daily steps in our study). Our findings provide practical implications for future EMA studies investigating context-specific effects on mental health outcomes. We also suggest clinical implications for promoting emotional well-being for public health organizations.