Section 096-140-14 - Ambient Air Quality AnalysisA.General Requirement. It shall be the burden of any applicant to provide an affirmative demonstration that its emissions, in conjunction with all other sources, will not violate ambient air quality standards, except that Part 70 sources in nonattainment areas or which significantly impact a nonattainment area shall be required to demonstrate that the Part 70 source's emissions are consistent with Reasonable Further Progress provisions of the State Implementation Plan. An applicant may use ambient air monitoring, modeling, or other assessment techniques as approved by the Department and shall be consistent with EPA regulations and guidelines or other requirements under the CAA. The analyses shall include relevant emissions units at the Part 70 source, meteorological and topographical data necessary to estimate such impacts, and shall consider the impact of fugitive emissions to the extent quantifiable, secondary emissions, and emissions from other existing sources including increases in mobile and area source emissions impacting the same area. The level of analysis shall depend upon the size of the Part 70 source, the regulated air pollutants emitted, existing air quality, proximity to Class I or nonattainment areas, or areas where increment has been substantially consumed. (For the purposes of this subsection, the Class I area includes any conservation easements under the jurisdiction of an appropriate Federal Land Manager as of August 7, 1977.) The air quality impact analysis, in general, will not be required of the applicant for those regulated pollutants that are not included in the definition of "significant emissions increase" in 06-096 C.M.R. ch. 100. The analysis shall be conducted pursuant to subsection 14(C) of this Chapter, Prohibited Dispersion Techniques, 06-096 C.M.R. ch. 116, and Appendix W to 40 C.F.R. Part 51 - Guideline on Air Quality Models.
Air quality modeling conducted as part of the licensing of a new Part 70 source or modification to a Part 70 source in the United States is substantially governed by the Appendix W to 40 C.F.R. Part 51 - Guideline on Air Quality Models. That modeling guidance was first promulgated in 1978 and, by law, must be routinely updated by EPA. Thus, federal regulatory guidance on modeling and the list of acceptable models do change. The Department recognizes that air dispersion modeling guidance will be periodically updated to reflect the latest federal guidance. To maintain an orderly licensing process in the State, applicants will be required to conform with those procedures and guidelines in effect at the time of Department approval of a written modeling protocol that meets all applicable requirements provided the applicant completes modeling, as approved, and submits its results within six months of the date of approval of the protocol. If the protocol calls for collection of on-site meteorological data, then the starting date for the on-site data collection must be no later than six months after approval of the protocol, and modeling results must be submitted within six months of obtaining acceptable on-site meteorological monitoring data. Requests by the applicant to modify the modeling protocol will require conformance with current applicable air dispersion modeling guidance.
(1)Ambient Air Quality Monitoring Requirements. Monitoring done by the owner or operator shall conform to the requirements of 40 C.F.R. Part 58, Appendix B and the Department's Quality Assurance Plan (or other plan approved by the Department) during the operation of monitoring stations. It is recommended that a written protocol be developed by the owner or operator and the Department when a Part 70 source is required to conduct either pre-construction or post-construction monitoring. The protocol shall, at a minimum, specify the monitoring sites, frequency of sampling, data recovery, pollutants, and monitoring method(s).(2)Air Quality Impact Modeling Requirements(a) All estimates of ambient concentrations required by an ambient or increment impact analysis shall be based on the relevant air quality models, data bases, and other requirements specified in the current Appendix W to 40 C.F.R. Part 51 - Guideline on Air Quality Models, and in accordance with subsection 14(C) of this Chapter, and 06-096 C.M.R. ch. 116. Fugitive emissions, to the extent quantifiable, shall be considered.(b) All input, output and diagnostic files used in the final Class I and Class II standards and increment compliance modeling analyses and Class I AQRV and visibility modeling analyses shall be submitted to the Department on media formatted for use by computer software which the Department uses unless otherwise approved by the Department.(c) Where an air quality impact model specified in the Appendix W to 40 C.F.R. Part 51 - Guideline on Air Quality Models is inappropriate, the model may be changed or another model substituted; such change or substitution shall be subject to public comment and the written acceptance of the Department and the EPA Regional Administrator or their designee. Methods such as those outlined in the Protocol for Determining the Best Performing Model (EPA-454/R-92-025) and the Interim Procedures for Evaluating Air Quality Models: Experience with Implementation (EPA-450/4-85-006) should be used to determine the comparability of air quality models.B.Renewal of a Part 70 License(1) A previously submitted impact analysis shall be acceptable unless:(a) It has been found to be deficient with respect to requirements set forth in subsection 14(A) of this Chapter;(b) The impact analysis fails to reflect available information with respect to ambient air quality levels in the area, which, based upon the Department's expertise, may reasonably be expected to be significantly impacted by the Part 70 source;(c) The Part 70 source emits a regulated pollutant for which an ambient air quality standard has been adopted and whose impact was not addressed in the original impact analysis; or(d) There are changes in stack or building configurations or other factors which are determined to significantly alter the dispersion characteristics of the Part 70 source.(2) Continuation of an ambient air monitoring or meteorological monitoring program will be made on a case-by-case basis at the time of the renewal. It is the burden of the applicant to demonstrate the adequacy of existing data; its relationship to past, present, and future facility operating conditions; and the adequacy of other means to document continuing compliance.(3) An existing Part 70 source is exempt from an impact analysis with respect to a regulated pollutant whose allowable emissions, after the application of control technology requirements specified in Section 4 of this Chapter, do not exceed the following, unless the Part 70 source is located in or near a Class I area or an area where the available air quality is limited, or other extenuating circumstances exist: (a) 50 tons per year (tpy) for SO2;(d) 15 tpy for PM2.5 direct emissions;(e) 50 tpy for NOx (measured as NO2);(f) 0.6 tpy for Lead (Pb); and(g) 0.2 tpy of total Chromium.C.Modeling/Data Collection Protocol. Any air quality dispersion modeling or data collection program shall be developed consistent with the following requirements:(1)Guidance. All air quality dispersion modeling and meteorological data collection shall be conducted consistent with Section 14 of this Chapter and Appendix W to 40 C.F.R. Part 51 - Guideline on Air Quality Models. NOTE: For major sources and major modifications, the applicant should consult with the Department and Federal Land Managers (potentially affected federal lands are listed in Classification of Air Quality Control Regions, 06-096 C.M.R. ch. 114) if Class I analyses are required, prior to submitting a modeling/data collection protocol. The applicant is responsible for obtaining the training necessary to perform the required air dispersion modeling and meteorological data collection.
(2)Variance from Guidance. Upon an applicant's written request, the Department may grant a variance from any of the requirements set forth in Section 14 of this Chapter and Appendix W to 40 C.F.R. Part 51 - Guideline on Air Quality Models, when the Department finds that the alternative proposed by the applicant will not significantly affect the accuracy of the modeling, or when data collection results or compliance with the requirements specified in Section 14 of this Chapter and Appendix W to 40 CFR Part 51 - Guideline on Air Quality Models is technically infeasible or economically unreasonable for the applicant. For any Part 70 source subject to Prevention of Significant Deterioration (PSD) review, the variance shall be subject to EPA review and written approval and shall be subject to notice and opportunity for public comment pursuant to 40 C.F.R. Parts 51.160(f)(2) and 51.166 (l) (2).(3)Significant Impact Modeling Protocol for SO2, NO2, CO, PM2.5, and PM10. Prior to undertaking significant impact modeling for SO2, NO2, CO, PM2.5, and PM10, the applicant shall provide in writing to the Department, a description of the following factors that the applicant proposes to use in the significant impact modeling demonstration (see Appendix W to 40 C.F.R. Part 51 - Guideline on Air Quality Models for more specific guidance):(a) Operating scenarios, emissions units, and emission rates in English and metric units;(b) Regulated air pollutants;(c) Model(s) and methodologies;(d) Origin and period of meteorological data, including location of collection site relative to facility, meteorological parameters, instrument height, recovery rates, substitution techniques, and quality assurance and quality control (QA/QC) procedures;(e) Receptor grid (listing of coordinates and elevations, topographic maps covering the receptor grid area map of receptors). A listing of all Digital Elevation Model (DEM) quadrangles used and method(s) used to convert DEM data to the proposed receptor grid shall also be included. If DEM data is being used to create a rectangular receptor grid, then the elevation of each receptor point shall be the highest elevation within the grid cell. The grid cell is defined as an area enclosed by boundaries located half way to the nearest receptor in each direction;(f) Any special (e.g., fenceline, air intake, or flagpole) receptors;(g) Identity of emissions units and emissions which are included in baseline;(h) A properly scaled plot plan of the proposed facility with clearly marked true north indicator, building heights, and an accurate scale ruler. Also, show the location of the source on a map or aerial photograph of the area; and NOTE: An original plot plan is preferred, but if a photocopy is submitted, care should be taken to make sure that the scale is not changed on any area of the plot.
(i) Building dimension and Good Engineering Practice (GEP) analysis techniques. For each stack, all buildings that are large enough and close enough to influence the stack should be considered in the GEP analysis. As expeditiously as possible and within 30 calendar days of receipt of this information, the Department will notify the applicant in writing that such information is complete and acceptable for modeling or notify the applicant in writing of the reason(s) why the information is not complete. If the information is not complete, the Department will clearly identify the changes or additional information that must be submitted to complete the protocol requirements.
(4)Submittal of Significant Impact Modeling(a) Prior to undertaking the final air quality dispersion modeling demonstration, the applicant shall submit the following for review:(i) Significant impact modeling results (If all modeled impacts of any regulated pollutant are below the significant impact levels for all averaging periods, then no further analysis is necessary for that pollutant);(ii) Emissions data for regulated pollutants not in the significant impact modeling protocol;(iii) A preliminary analysis of nearby sources that will not be included in the background concentration analysis; NOTE: The Department is responsible for the final decision of off-site sources to be modeled. The Department will provide the applicant with a list of any additional sources that may have to be included in the final modeling analysis and the requisite model input data for these sources. This list will contain all data required for model input including source location(s), emission rates, stack parameters, and necessary building dimensions for the applicant to determine direction-specific building parameters.
(iv)Background Concentration Data. Conservative background values are available from the Department for all areas of the state. Should the applicant choose not to use the conservative background values supplied by the Department, the applicant shall be responsible for determining background values based on data normally supplied by and in consultation with the Department. For sources needing more refined background values, general guidance on determining background determinations based on monitoring data is provided in the most recent version of the Department's Guideline Document for Background Air Quality Determinations. Particular care must be taken when determining background values so that they do not implicitly include any impacts of the source(s) being modeled in order to avoid double counting; and(v)Processed Meteorological Data Base (if required by the Department). The use of five consecutive years of off-site National Weather Service (NWS) meteorological data (or other data equivalent or better in accuracy and detail to the NWS data) or at least one year of site-specific data is the minimum requirement for modeling applications. If more than one year (and up to five years) of acceptable data is available, it shall be used in the air quality analysis. If there is a gap in data from a catastrophic incident or a persistent but subtle problem that evades detection, a two, three, four, or five year on-site meteorological database acceptable for modeling purposes need not be compiled from two, three, four, or five consecutive years or 24, 36, 48, or 60 consecutive months of data. If this is the case, then the applicant shall write to the Department requesting an exemption from the consecutive two, three, four, or five year database requirement. If data requirements, source configurations or characteristics of the surrounding area change, the database may need to be updated after consultation with the Department. However, a requirement to collect a new database will neither preclude the applicant's ability to use the existing database in the interim data collection period nor require the applicant to repeat any previously submitted analyses that used the original database.(b) Within 30 calendar days of receipt of this information, the Department will notify the applicant of the following in writing: (i) The submitted information is complete and acceptable for modeling or the reason(s) why the information is not complete or acceptable. If the information is not complete or acceptable, the Department will clearly identify the changes or additional information that must be submitted to complete the protocol requirements; and(ii) For each regulated pollutant for which there are significant impacts, the Department will specify which operating scenarios and other nearby sources, if any, needs to be further modeled. If the applicant requests in writing, information in the possession of the Department that is required for modeling (for example, emissions which are included in baseline emissions, background data or other emissions data from nearby sources), the Department will provide any available information it has responsive to the request to the applicant within 30 calendar days.
(5)Air Quality Dispersion Modeling Protocol. If impacts from SO2, NO2, CO, PM2.5, and PM10 are above significance or if there are other regulated pollutants to be modeled, then the applicant must provide in writing to the Department, a description of the following factors (if different from previously submitted data) that the applicant proposes to use in the air quality dispersion modeling (see Appendix W to 40 C.F.R. Part 51 - Guideline on Air Quality Models for more specific guidance): (a) Operating scenarios, emissions units, and emissions in English and metric units (including other nearby sources, if necessary);(b) Regulated air pollutants;(c) Model(s) and methodologies;(d) Origin and period of meteorological data, including location of collection site relative to facility, meteorological parameters, instrument height, recovery rates, substitution techniques, and QA/QC procedures;(e) Receptor grid (listing of coordinates and elevations, topographic maps covering the receptor grid area, map of receptors and, if applicable, a listing of all DEM quadrangles used and method(s) used to convert DEM data to the proposed receptor grid). If DEM data is being used to create a rectangular receptor grid, then the elevation of each receptor point shall be the highest elevation within the grid cell. The grid cell is defined as an area enclosed by boundaries located half way to the nearest receptor in each direction;(f) Any special (e.g., fenceline, air intake, or flagpole) receptors;(g) Identity of emissions which are included in baseline emissions;(h) A properly scaled plot plan of the proposed facility with clearly marked true north indicator, building heights and an accurate scale ruler. Also, show the location of the source on a map of the area; NOTE: An original plot plan is preferred, but if a photocopy is submitted, care should be taken to make sure that the scale is not changed on any area of the plot.
(i)Building Dimension and Good Engineering Practice Analysis Techniques. For each stack, all buildings that are large enough and close enough to influence the stack should be considered in the GEP analysis. Submit all building profile input program (BPIP) input and output files on media approved by the Department. All tiers of a building will be input as tiers and not as separate buildings; and(j)Background Concentration DataWithin 30 calendar days of receipt of this information, the Department will notify the applicant in writing that such information is complete and acceptable for modeling or notify the applicant in writing of the reason(s) why the information is not complete or acceptable. If the information is not complete or acceptable, the Department will clearly identify the changes or additional information that must be submitted to complete the protocol requirements.
When all submitted information is considered complete and acceptable for modeling, the applicant shall perform air quality dispersion modeling and submit for review the air quality dispersion modeling analysis as part of the final application submittal.
(6)Presentation of Final ResultsOnce compliance with ambient air quality standards, ambient increments, and other limitations has been demonstrated through modeling, the applicant shall prepare a written report documenting the source being modeled, the modeling effort, and a compliance demonstration. The following information is required in the written report and information required to be submitted on media approved by the Department.
(a) Introduction (briefly provide an overview of the project, the analyses conducted, and the results);(b) Site and surroundings (describe the topography, demography, air quality control region, and compliance status (attainment/nonattainment); include a topographic map section showing the site and a properly scaled plot plan of the proposed facility; include rural/urban classification and simple/complex terrain determination, topography and land-use described in sufficient detail to specify roughness length if roughness length is a required input for the modeling system used in the analysis;(c) Source description (provide an overview of the source, describe the process(es) involved);(d) Description of each emissions unit at the source (describe the equipment/operations, emissions controls, emissions limits; list emissions and stack parameters for each emissions unit in English and metric units);(e) Screening modeling (describe the screening analyses performed): (i) Modeling approach/model(s) used;(iii) Model switch selections;(iv) Source data (affected source and other nearby sources);(f) Final compliance modeling analysis, (describe in detail modeling performed and results): (i) Modeling approach/model(s) used;(iii) Model switch selections;(iv) Source data (affected source and other nearby sources);(v) Meteorological data base. The meteorological data base shall be submitted on media approved by the Department if the applicant processed the meteorological data base;(vi) Receptor data. A map of the receptor grid shall be submitted. (If applicable, all DEM data used to create the receptor grid shall be submitted on media approved by the Department); and(vii) Modeling results (all input files needed to duplicate the final compliance model runs and all final compliance model output and diagnostic files shall be submitted on media approved by the Department).(g) Compliance demonstration (describe how the predicted concentrations comply with all applicable ambient air quality standards and ambient increments):(i) Background determination (include table of values);(ii) Compliance with ambient air quality standards; and(iii) Compliance with Class II Prevention of Significant Deterioration (PSD) increments (if applicable).(h) Class I area impact assessment, if required, (describe any analyses made for federal Class I areas):(i) Basis for assessment;(ii) Modeling approach/model(s) used;(iii) Model version used;(iv) Model switch selections;(v) Class I areas affected;(vi) Emissions and conditions of operating scenarios;(vii) Meteorological data;(x) Air quality impacts (ambient air quality standards and ambient increments);(xi) Visibility (plume blight assessment for regions within a Class I area that are affected by plumes or layers that are viewed against a background generally within 50 kilometers of the source) and regional haze assessment (for regions of a Class I area where visibility impairment from the source would cause a general alteration of the appearance of the scene generally 50 kilometers or more away from the source or from the interaction of the emissions from multiple sources) and other assessments that the Federal Land Manager and the Department agree should be assessed; and(xii) All input files needed to duplicate the final Class I analysis model runs and all final Class I analysis model output and diagnostic files shall be submitted on media acceptable to the Department. NOTE: The Department recommends that any applicant likely to be required to conduct and submit an air quality dispersion modeling analysis meet at least once with Department staff prior to submitting the information specified in subsection 14(C)(5) of this Chapter. A failure by the Department to notify or provide information to the applicant as specified in this subsection does not constitute an approval of the proposed protocol or modeling.
06-096 C.M.R. ch. 140, § 14