Policies tackling target environmental impacts can affect other aspects of environmental quality adversely or beneficially, which brings about questions on trade-offs or co-benefits. The passenger car fleet contributes an important part of total emissions driving concerns on both climate change and nitrogen cycle disturbance. In the present study, we investigated simultaneously the time series greenhouse gas and reactive nitrogen emissions of the Japanese passenger car fleet from a life cycle perspective. The integrated model which consists of the dynamic material flow sub-model and life cycle analysis sub-model was used for the analysis. The results indicated that the stock of passenger cars had a relatively small variation at approximately 50 million yet with rapid evolving stock composition from 2000 to 2030, which resulted in a change in energy consumption structure. The emission of greenhouse gas achieved a reduction of 35% by 2030 compared to 2005. Remarkably, the emission of reactive nitrogen was reduced by 66% within this same period. The greenhouse gas emission is mainly stemmed from the Tank to Wheel (TTW) stage. As for reactive nitrogen, the emission from TTW stage was higher than that from Well to Tank (WTT) stage from 2000 to 2013, whereas it reversed from 2013 to 2030. Finally, policy implications were presented based on energy consumption structure change, mitigation effort shift and contribution of key pollutant species.

解决目标环境影响的政策可能对环境质量的其他方面产生不利或有利影响，这带来了有关权衡或共同利益的问题。在气候变化和氮循环扰动方面，乘用车车队是排放总量驱动因素的重要组成部分。在本研究中，我们从生命周期的角度同时研究了日本乘用车车队的时间序列温室气体和活性氮排放。使用由动态物料流子模型和生命周期分析子模型组成的集成模型进行分析。结果表明，从2000年到2030年，乘用车的存量变化相对较小，约为5000万，但存量构成迅速变化，导致能源消耗结构发生变化。与2005年相比，到2030年温室气体的排放量减少了35％。值得注意的是，同一时期内活性氮的排放量减少了66％。温室气体排放主要源于“罐转轮”（TTW）阶段。至于活性氮，从2000年到2013年，TTW阶段的排放量高于从油井到储罐（WTT）阶段的排放量，而从2013年到2030年则相反。最后，根据能源消耗结构的变化，缓解措施提出了政策含义。关键污染物种类的转移和贡献。温室气体排放主要源于“罐转轮”（TTW）阶段。至于活性氮，从2000年到2013年，TTW阶段的排放量高于从油井到储罐（WTT）阶段的排放量，而从2013年到2030年则相反。最后，根据能源消耗结构的变化，缓解措施提出了政策含义。关键污染物种类的转移和贡献。温室气体排放主要源于“罐转轮”（TTW）阶段。至于活性氮，从2000年到2013年，TTW阶段的排放量高于从油井到储罐（WTT）阶段的排放量，而从2013年到2030年则相反。最后，根据能源消耗结构的变化，缓解措施提出了政策含义。关键污染物种类的转移和贡献。