Tourism affects not only the tourism industry but also society and stakeholders such as the environment, local businesses, and residents. Tourism Recommender Systems (TRS) can be pivotal in promoting sustainable tourism by guiding travelers toward destinations with minimal negative impact. Our paper introduces a composite sustainability indicator for a city trip TRS based on the users' starting point and month of travel. This indicator integrates CO2e emissions for different transportation modes and analyses destination popularity and seasonal demand. We quantify city popularity based on user reviews, points of interest, and search trends from Tripadvisor and Google Trends data. To calculate a seasonal demand index, we leverage data from TourMIS and Airbnb. We conducted a user study to explore the fundamental trade-offs in travel decision-making and determine the weights for our proposed indicator. Finally, we demonstrate the integration of this indicator into a TRS, illustrating its ability to deliver sustainable city trip recommendations. This work lays the foundation for future research by integrating sustainability measures and contributing to responsible recommendations by TRS.

翻译：旅游业不仅影响旅游产业，还涉及社会及环境、本地商业、居民等多方利益相关者。旅游推荐系统（TRS）通过引导旅行者选择负面影响最小的目的地，可在促进可持续旅游方面发挥关键作用。本文提出一种基于用户出发点和旅行月份的城市旅行TRS复合可持续性指标。该指标整合了不同交通方式的CO2e排放量，并分析了目的地热门度与季节性需求。我们基于Tripadvisor和Google Trends数据的用户评论、兴趣点及搜索趋势量化城市热门度。为计算季节性需求指数，我们利用TourMIS和Airbnb的数据。通过开展用户研究，我们探索了旅行决策中的基本权衡关系，并确定了所提出指标的权重系数。最后，我们展示了该指标在TRS中的集成方案，证明其能够提供可持续的城市旅行推荐。本研究通过整合可持续性度量指标，为TRS实现负责任推荐奠定基础，并为未来研究开辟道路。