Mental health and well-being can be related to both individual as well as environmental factors. In order to address the latter relationship we use an Ecological Momentary Assessment (EMA) approach to capture the mood of 10 persons in real-time and real-life via questionnaires sent to their smartphones. This paper focuses on the timing of the questionnaire trigger. In order to avoid the questionnaires being triggered simply at fixed time intervals, we add a spatial component incorporating the land use associated with the participant’s location. The results show that the introduced trigger, which can send out an electronic questionnaire when a person moves to an area with a different land use, results in more unique trigger positions and displays an increase of triggers at less frequently visited land uses. This helps obtain a spatial spreading of the questionnaires.