外界微量影响物

例句：

1. 1. The small amount of pollutants in the air can have a significant effect on human health.
   空气中的少量污染物对人类健康有显著影响。
2. 2. The researcher found that the microbes in the soil had a minimal influence on the plant growth.
   研究人员发现土壤中的微生物对植物生长几乎没有影响。
3. 3. The decision to invest in renewable energy sources has a minor influence on global warming.
   投资可再生能源的决定对全球变暖的影响微乎其微。