### Question
How does PROGRAMS AND ACTIVITIES define modification?


### Answer
Under *42 U.S.C. § 7412*, **modification** is defined as:

> any physical change in, or change in the method of operation of, a major source which increases the actual emissions of any hazardous air pollutant emitted by such source by more than a de minimis amount or which results in the emission of any hazardous air pollutant not previously emitted by more than a de minimis amount

#### Citation:
  - *42 U.S.C. § 7412*
  - Heading: **CHAPTER 83-ENERGY EXTENSION SERVICE > SUBCHAPTER I-PROGRAMS AND ACTIVITIES > Part A-Air Quality and Emission Limitations**

