### Question
What does existing source mean?


### Answer
**Existing source** has the following meaning in *42 U.S.C. § 7412*:

> any stationary source other than a new source

#### Citation:
  - *42 U.S.C. § 7412*
  - Heading: **CHAPTER 85-AIR POLLUTION PREVENTION AND CONTROL > SUBCHAPTER I-PROGRAMS AND ACTIVITIES > Part A-Air Quality and Emission Limitations**

