source of atmospheric pollution

例句：

1. 1. The source of the pollution isoften difficult to trace.
   污染的来源往往难以追踪。
2. 2. The scientist discovered a new source ofenergy.
   科学家发现了一种新的能源来源。
3. 3. The company's success can be traced backto its innovative source of technology.
   公司的成功可以追溯到其创新的技术来源。