soot concentration

例句：

1. 1.The engine's performance is directly related to the soot concentration in the exhaust.
   发动机的性能与排气中的烟灰浓度直接相关。
2. 2. Scientists are studying how to reduce the soot concentration in power plants.
   科学家们正在研究如何减少发电厂的烟灰浓度。
3. 3.The factory has implemented stricter emission standards to control the soot concentration in the air.
   该工厂已实施更严格的排放标准，以控制空气中的烟灰浓度。