Pollution type and emission reduction

（一）Different types of pollution

1. 按照污染物种类分类

• Air pollution
• Greenhouse gas emissions (GHGs)：严格来说温室气体不属于污染，但是很多空气污染的来源和温室气体的来源是相同的 （ep 燃料燃烧），因此需要协同治理，减污降碳。
• Water pollution
• Noise pollution
• Soil pollution

2. 按照污染源分类

• Point source pollution (点源污染)
  • Easy to identify the source and measure the pollution level
  • Example: Industrial pollution
• Nonpoint source pollution (面源污染)
  • Difficult to identify the source and measure the pollution level
  • Example: Agricultural pollution from fertilizer (化肥)
  • More practical for indirect regulation, e.g. limiting the use of inputs that contribute to pollution【间接监管更好用】

（二）emission reduction

1. emission moedel

• Emission intensity（排放强度）:每单位产出带来的污染
• Output（产出）：f公司的产出总量
• 因此减排存在两个途径：1）减少排放强度；2）减少产出

2. Reducing emission intensity

• Change input mix (改变投入品组合)
  • Use renewable energy instead of fossil fuels
  • Improve energy efficiency
• End-of-pipe treatment (末端治理)：排放出来之后进行处理