Model Clearinghouse Information Storage and Retrieval System
Record Details

Issue:

The New York State Department of Environmental Conservation’s 
(NYSDEC) formally submitted a request  to the U.S. Environmental 
Protection Agency (EPA) Region 2 on June 28, 2022, to use 
alternate modeling approaches to conduct its modeled attainment 
demonstration of the 1-hour Sulfur Dioxide (SO2) National Ambient 
Air Quality Standard (NAAQS) for the Alcoa Massena West aluminum 
smelter located in St. Lawrence County, New York. The modeled 
attainment demonstration is a required component for approval and 
incorporation into the NYSCEC’s State Implementation Plan (SIP) 
with respect to the portion of St. Lawrence County that was 
designated as non-attainment through the Round 4 1-hour SO2 NAAQS 
designation process.

The NYSDEC is requesting approval to use two case-specific 
alternative model approaches which modify inputs to the EPA 
preferred model, AERMOD (American Meteorological Society/
Environmental Protection Agency Regulatory Model). Specifically, 
the two requested alternative model approaches include the 
(1) substitution of a neutral temperature lapse rate in the lower 
100 meters of the atmosphere and (2) use the 2019 draft version 
of BPIPPRM (Building Profile Input Program for PRIME, Plume Rise 
Model Enhancements). The NYSDEC is seeking alternative model 
approval under the under the Guideline on Air Quality Models 
(40 CFR Part 51, Appendix W) Section 3.2.2(b), Condition (2).

EPA Region 2 finds that the proposed alternative model approaches 
and accompanying model performance evaluation adequately address 
the requirements of the Guideline, Section 3.2.2(b)(2) and Section 
3.2.2(d). As such, pursuant to Sections 3.0(b) and 3.2.2(a) of the 
Guideline, EPA Region 2 intends to approve the alternative model 
approaches proposed for the modeled attainment demonstration for 
the Alcoa Massena West aluminum smelter.

C/H Response:  

The Model Clearinghouse fully concurs with EPA Region 2’s proposed 
approval of the two alternative model approaches for use by NYSDEC 
in its modeled attainment demonstration of the 1-hour SO2 NAAQS 
for the Alcoa Massena West aluminum smelter located in St. 
Lawrence County, New York. The EPA Region 2 review and the NYSDEC 
and Alcoa documentation provide a sufficient theoretical basis and 
supporting scientific justification for the use of these 
alternative model approaches. This Model Clearinghouse concurrence 
and the EPA Region 2 alternative model approval for these two 
alternative model approaches should be considered case-specific 
and any further regulatory application of these alternative model 
approaches would require further review and approval per the 
requirements of the Guideline, Section 3.2.

Note:

While BPIPPRM is not technically a regulatory portion of the 
AERMOD Modeling System and does not require alternative model 
approval by EPA, the transmittal memorandum associated with the 
release of the 2019 draft BPIPPRM does state that the draft 
version of BPIPPRM cannot be used in regulatory applications of 
AERMOD. Thus, any potential regulatory use of the 2019 draft 
BPIPPRM can only be done through coordination and consultation 
with the appropriate reviewing authority, EPA Regional Office, 
and the Model Clearinghouse.

Memo:  Model Clearinghouse review of the use of case-specific alternative 
approaches to demonstrate modeled attainment of the 2010 SO2 NAAQS 
at the Alcoa West aluminum smelter in Massena, New York
        Dated: October 14, 2022
        From:  George Bridgers, Model Clearinghouse Director
                 Air Quality Modeling Group, Air Quality Assessment Division, 
                 Office of Air Quality Planning and Standards
        To:    Annamaria Colecchia, Regional Air Quality Modeler
                 Permitting Section, Air Programs Branch, Air and Radiation Division
                 EPA Region 2, New York, New York
               Rick Ruvo, Director
                 Air and Radiation Division
                 EPA Region 2, New York, New York
                 
Memo:  Concurrence Request to Use Site Specific Alternative Approaches to 
Demonstrate Modeled Attainment of the 2010 SO2 NAAQS at the Alcoa 
West Aluminum Smelter in Massena, New York
        Dated: September 20, 2022
        From:  Annamaria Colecchia, Regional Air Quality Modeler
                 Permitting Section, Air Programs Branch, Air and Radiation Division
                 EPA Region 2, New York, New York
        Thru:  Rick Ruvo, Director
                 Air and Radiation Division
                 EPA Region 2, New York, New York
        To:    George Bridgers, Model Clearinghouse Director
                 Air Quality Modeling Group, Air Quality Assessment Division, 
                 Office of Air Quality Planning and Standards

Memo:  New York State Department of Environmental Conservation (NYSDEC) 
Alternative Model Request
        Dated: June 28, 2022

Modeling Protocol:  SO2 Modeling Protocol for Alcoa Massena Operations - West Plant
        Dated: June 10, 2022

Expert Opinion Paper:  Review of LIFTOFF Model as AECOM has Implemented into AERMOD
 - Steven Hanna
        Dated: February 6, 2022