SIP - ALASKA - 18 AAC 50.215
18 AAC 50.215. AMBIENT AIR QUALITY ANALYSIS METHODS
(a) A person who submits ambient air monitoring data under AS 46.03, AS 46.14, or this chapter shall obtain the data in accordance with
(1) the department's Alaska Quality Assurance Manual For Ambient Air Quality Monitoring, adopted by reference in 18 AAC 50.030, for PM-10, total suspended particulates (TSP), lead, carbon monoxide, nitrogen dioxide, sulfur dioxide, and ammonia;
(2) a reference method or an equivalent method described in 40 C.F.R Part 50, adopted by reference in 18 AAC 50.035, for ozone; or
(3) an alternative method that is representative, accurate, verifiable, capable of replication, and approved by the department.
(b) Except as provided in (c) of this section, a person who submits an analysis performed to predict ambient air quality conditions shall
(1) ensure that estimates of ambient concentrations and impairment to visibility are based on applicable air quality models, databases, and other requirements specified in the EPA's Guideline on Air Quality Models (Revised), adopted by reference in 18 AAC 50.030; and
(2) for comparing predicted or measured ambient concentrations of an air pollutant to a maximum allowable increase established under 18 AAC 50.020(b)(2), exclude
(A) concentrations attributable to a temporary construction activity for a new or modified source; and
(B) the increase in concentrations attributable to new sources outside the United States over the concentrations attributable to existing sources included in the baseline concentration.
(c) A person may substitute or modify an air quality model referenced in (b) of this section only after
(1) obtaining approval from the department for a protocol to be used in performing the analysis required by (2) of this subsection;
(2) undertaking and submitting a comparative analysis of the air quality models using the approved protocol, which must be fashioned after those outlined in the EPA's Workbook for Comparison of Air Quality Models and Interim Procedures for Evaluating Air Quality Models (Revised), adopted by reference in 18 AAC 50.030; and
(3) obtaining approval from the federal administrator and the commissioner for the substitution or modification if an ambient air quality analysis is required by 18 AAC 50.306.
(d) Table 5 establishes the significant impact level, expressed as micrograms per cubic meter, for each pollutant and averaging time. If the ambient impacts from emissions from a stationary source or modification are less than the concentrations in Table 5, the emissions are not considered to cause or contribute to a violation of an ambient air quality standard or maximum allowable increase for a Class II area.
Table 5. Significant Impact Levels (SILs)
| Pollutant | Annual | Averaging time (hours) |
 | | 24 | 8 | 3 | 1 |
| Sulfur dioxide…… | 1.0 mg/m3 | 5 mg/m3 | ……….. | 25 mg/m3 | ……….. |
| PM-10……... | 1.0 mg/m3 | 5 mg/m3 | ……….. | ……….. | ……….. |
| Nitrogen dioxide…. | 1.0 mg/m3 | ……….. | ……….. | ……….. | ……….. |
| Carbon monoxide… | ……….. | ……….. | 500 mg/m3 | ……….. | 2000 mg/m3 |
State effective: 10/1/04; EPA effective: 9/13/07