The greenhouse gas emissions footprint and global warming potential are widely-used for environmental sustainability studies. However, environmental sustainability is far wider than carbon emissions and climate change. This review aims to highlight the importance of considering air pollutants in optimisation studies and evaluate the limitation of the current assessments for air emissions, particularly in relation to transportation. The source of air pollutants is firstly overviewed with special attention on non-stationary sources, freight and sea transportation. The type of measurement to obtain the emission data and the available optimisation models on transport mode choice selection were then summarised. The strengths and Weaknesses' have been indicated. The identified gap includes greenhouse gas and air pollutants not being evaluated simultaneously and the interaction between the different pollutants are not being adequately considered. A better assessment framework and impact categories classification are consequently required. The summarised assessment model of transportation mode choice shows that the current viewpoint on low emissions, green or environmental sustainability options refers to carbon dioxide as a part of greenhouse gas. Attention towards a better emission assessment and management has been supported in this study through critical discussion. The next step of this work is to develop a methodology to measure greenhouse gas and air pollutants simultaneously by considering the synergistic effect and the discussed limitation. It is important for minimising the potential of footprint shifting and poor decision-making.

温室气体排放足迹和全球变暖潜力已广泛用于环境可持续性研究。但是，环境的可持续性远远超过碳排放和气候变化。这篇综述旨在强调在优化研究中考虑空气污染物的重要性，并评估当前的空气排放评估的局限性，尤其是在运输方面。首先概述了空气污染物的来源，特别关注非固定来源，货运和海上运输。然后总结了获得排放数据的测量类型和关于运输模式选择的可用优化模型。已经指出了优势和劣势。所确定的差距包括未同时评估的温室气体和空气污染物，并且未充分考虑不同污染物之间的相互作用。因此，需要更好的评估框架和影响类别分类。运输模式选择的总结评估模型表明，当前关于低排放，绿色或环境可持续性选择的观点是将二氧化碳作为温室气体的一部分。本研究通过批判性讨论支持了对更好的排放评估和管理的关注。这项工作的下一步是通过考虑协同效应和所讨论的局限性，开发一种同时测量温室气体和空气污染物的方法。