(1) 
Applicability. This section describes the procedures that shall be used for quantifying emissions and analyzing impacts of toxic air contaminants in order to meet the requirements for new or modified toxic air contaminant sources (see TTC § 8.25.420(5)) and for existing toxic air contaminant sources.
(2) 
Quantifying Emissions of Toxic Air Contaminants.
(a) 
The owner or operator of a new or modified toxic air contaminant emissions source that may be discharged to the atmosphere after applying the required control technology, and shall submit this information as part of a Notice of Construction and Application for Approval.
(b) 
The owner or operator of an existing toxic air contaminant source, upon request by the Department, shall quantify toxic air contaminant emissions emitted by the facility and submit that information within 30 days.
(c) 
The following assumptions shall be made when quantifying toxic air contaminant emissions:
(i) 
Each toxic air contaminant is introduced into the atmosphere in an unaltered form continuously, at the maximum concentration known to exist at the source, unless there is reliable data to the contrary or there is a physical or legal restriction.
(ii) 
Dioxin and furan emission shall be combined as one toxic air contaminant, equivalent in potency to 2,3,7,8-Tetrachlorodi-benzo-p-dioxin.
(iii) 
Benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene, dibenz(a,h)anthrancene, indeno(1,2,3-cd)pyrene, and benzo(a)pyrene shall be combined as one toxic air contaminant equivalent in potency to benzo(a)pyrene.
(3) 
Analyzing Impacts of Toxic Air Contaminants. The air quality impact analysis for toxic air contaminant sources shall be performed using one of the following procedures:
(a) 
The EPA guideline dispersion model, TSCREEN, shall be used to demonstrate that the predicted concentration of each contaminant is below the corresponding acceptable source impact level listed in Appendix A, attached to the ordinance codified in this chapter. Stack parameters shall be submitted within the Notice of Construction Application, or, for existing sources, within 30 days after the Department requests the information. The maximum one-hour concentration calculated by the model shall be converted with a persistence factor of 0.4 to a 24-hour average concentration or 0.08 to an annual average concentration;
(b) 
The owner or operator shall submit a more comprehensive evaluation including the use of other EPA guideline models and more accurate emission estimation techniques to demonstrate that the predicted concentration of each contaminant below the corresponding acceptable source impact level listed in Appendix A, attached to the ordinance codified in this chapter in all areas where the general public has access; or
(c) 
If predicted ambient concentrations are not below the acceptable source impact levels listed in Appendix A, attached to the ordinance codified in this chapter, the owner or operator shall submit a risk analysis following the procedures in WAC 173-460-090(4), which demonstrates that emissions from the source will not cause air pollution.
(Ord. 96 § 10.03, 6-7-1997 (Res. 97-0118))