He notes that there are three categories of environmentally friendly materials. The first are materials that naturally decompose into harmless compounds, the second are recyclable or reusable materials, and the third are those that can be incinerated without emitting toxins.
他指出，環保分成 3 級，第一級是材料可以回歸大自然、自然分解腐化；第二級是可回收再利用；第三級則是焚燒時不產生毒氣。