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本身，还对环境、本地企业和居民等社会利益相关方产生深远影响。旅游推荐系统（TRS）可通过引导游客选择负面影响最小的目的地，在推动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地及出行月份的城市旅游TRS综合可持续性指标。该指标整合了不同交通方式的二氧化碳排放当量，并分析了目的地流行度与季节性需求。我们基于Tripadvisor和Google Trends的用户评论、兴趣点及搜索趋势数据量化城市流行度，同时利用TourMIS与Airbnb数据计算季节性需求指数。通过用户研究探索旅行决策中的基本权衡关系，并确定所提出指标的权重。最后，我们展示了该指标与TRS的集成应用，验证其在提供可持续城市旅游推荐方面有效性的能力。本研究通过整合可持续性评估指标，为未来相关研究奠定基础，并推动TRS提供负责任的推荐方案。