Their approach is flexible enough that in principle other important quality-of-life changes could be incorporated—for example, decreases in total emissions of pollutants and declines in crime rate.
2018年6月六级真题（第三套）阅读 Section C
柯林斯高阶英汉双解学习词典释义
N-VAR
污染物（尤指车辆尾气和工业有毒化学废弃物）
Pollutants are substances that pollute the environment, especially gases from vehicles and poisonous chemicals produced as waste by industrial processes.