Virginia Administrative Code
Title 9 - ENVIRONMENT
Agency 5 - STATE AIR POLLUTION CONTROL BOARD
Chapter 60 - HAZARDOUS AIR POLLUTANT SOURCES
Part II - Emission Standards
Article 4 - Emission Standards for Toxic Pollutants from Existing Sources (Rule 6-4)
Section 9VAC5-60-250 - Determination of ambient air concentrations

A. The owner shall, upon the request of the board, provide an assessment as to whether his facility emits, or may emit, any toxic pollutant in such quantities as to cause, or contribute to, any concentration exceeding, or which may exceed, any significant ambient air concentration.

B. Ambient air concentrations shall be determined using air quality analysis techniques (modeling) based on emission rates equal to the potential to emit of the stationary source for the applicable averaging time or any other method acceptable to the board.

C. Ambient air concentrations shall include all emissions from the stationary source, including those from sources exempted under 9VAC5-60-200 C.