机动车尾气污染因子季节变化特征及防控对策

Seasonal Variation Characteristics of Motor Vehicle Exhaust Pollutants and Prevention and Control Strategies

摘要: 机动车尾气是城市NO_x、CO、PM_2.5、VOCs的重要排放源，气象条件与季节变化会显著改变机动车污染物排放强度与组分构成。在国内移动源污染管控中，普遍采用全年统一管控模式，对污染物季节差异的考虑尚有不足。本文基于现有台架、车载实测与城市观测文献资料，系统归纳机动车常规污染物及VOCs的季节排放特征，解析温度、冷启动、尾气后处理、气象扩散条件对污染过程的驱动作用。研究发现，常规污染物CO、NO_x、PM_2.5冬季排放压力最大；VOCs存在尾气与蒸发排放的双途径，夏、冬两季污染来源与化学活性差异明显。结合季节污染风险，梳理分季节管控路径，为移动源精细化管控和后续相关研究提供参考。

Abstract: Vehicle exhaust is an important emission source of urban NO_x, CO, PM_2.5, and VOCs. Meteorological conditions and seasonal variations can significantly alter the emission intensity and component composition of vehicle-derived pollutants. In China’s mobile-source pollution management, a year-round unified control mode is generally adopted, which gives insufficient consideration to the seasonal differences of pollutants. Based on existing bench-scale tests, on-vehicle real-world measurements and urban observation literature, this paper systematically summarizes the seasonal emission characteristics of conventional vehicle pollutants and VOCs, and analyzes the driving effects of temperature, cold-start conditions, exhaust after-treatment devices and meteorological diffusion conditions on pollution processes. The results show that conventional pollutants, including CO, NO_x and PM_2.5, present the highest emission pressure in winter. VOCs have dual emission pathways of tail-pipe exhaust and fuel evaporation, with obvious differences in pollution sources and chemical reactivity between summer and winter. Combined with seasonal pollution risks, seasonal-targeted control approaches are sorted out. This work can provide references for refined mobile-source pollution control and future related research.