**¢~**' STATE OF MICHIGAN

## .,.,~~·--:::····cAE'"1 DEPARTMENT OF ENVIRONMr/KC'drJAl.'i'fY ·'

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. LANSING**·.t'~t** 

## ;i,l**·~ ~-~-** **~:il'** DAN WYANT RICK SNYDER

GOVERNOR



### Mr. George Czerniak, Director Air and Radiation Division May 9, 2013

United States Environmental Protection Agency Region 5 77 West Jackson Boulevard (A-18J) Chicago, Illinois 60604-3507 Dear Mr. Czerniak: 

# MAY 1 4

# 20131 DIRECTOR



### SUBJECT: Supplemental Information for the April 25, 2011, Submission, "Requestto Redesignate to Attainment Status for Both the Annual and 24-Hour PM 2.

### 5 NAAQS". The Michigan Department of Environmental Quality (MDEQ), Air Quality Division, is

.. - pleased !o provide-you with the attached adi:litionaiinformation tosupplementthe

### PM~.

## 5 redesignation request thatwassubmitted to the United States Environmental Protection Agency (USEPA) on April 25, 2011, titled "Request to Redesignate to Attainment Status for Both the Annual and 24-Hour PMz.5 NAAQS."The information provides details on the effect ofcontrols at a steel-making facility directly impacting the formerly-violating PM25air monitor in Dearborn, Michigan, and relates it to photochemical modeling ofthe area performed by the USEPA We believe the attached information will satisfy anyfurther concerns you may have with the redesignation request, and you will be able to propose approval in the nearfuture. If you have any questions regarding this submittal, please contact Mr. Robert Irvine, MDEQ, at 517-373-7042; irviner@michigan.gov; or you may contact me.

Enclosure cc/enc: Sincerely 

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# ·'/c**/~~~- ~··**  G. Vinson Hellwig, Chief " Michigan Department of Environmental Quality Air Quality Division 517-373-7069

Mr. John Summerhays, USEPA Ms. Carolyn Persoon, USEPA Mr. Jim Sygo, Deputy Director, MDEQ Ms. Lynn Fiedler, MDEQ Ms. Barb Rosenbaum, MDEQ Mr. Robert Irvine, MDEQ CONSTITUTION HALL • 525 WEST ALLEGAN STREET • P.O. BOX 30473 • LANSING, MICHIGAN 48909-7973 WIIVVI/.mlchlgan.gov/deq • (800) 662-9278

### local Scale Dispersion Modeli11g Support[ng Fine Particulate Matter {PM2.5) 

### Redesignation May 9, 2013 The Michigan Department of Environmental Quality (MDEQ) conducted local scale dispersion modeling using the United States Environmental Protection Agency (USEPA) AERMOD to determine the impacts of localized emission reductions at large industrial facilities in the vicinity of the air monitors showing modeled potential violations ofthe standard, from the USEPA Comprehensive Air Quality Modeling with Extensions (CAMX) modeling used in the Cross State Air Pollution Rule (CSAPR). This modeling showed approximately 1.49 micrograms per cubic meter (1Jg/m 3) annual reduction in PM2.5 and 8.7 1Jg/m3 daily reductions atthe Dearborn monitor as a result ofthe controls required at the Severstal Steel Company alone. For areas like the Dearborn monitor location, where local source primary emissions may contribute a sizable portion ofthe total PM25 (i.e., 10 to 30 percent ofthe total annual and daily average), use of a Gaussian dispersion model may work well for determining local primary impacts within a small area. Such modeling techniques have become known as local scale, or "hotspot" modeling. The process to determine neighborhood scale impacts generally follows the principles suggested in Section 5.3.2 ofthe USEPA Guidance on the Use of Models and OtherAnalyses for Demonstration Attainment ofAir Quality Goals for Ozone. PM2 5• and Regional Haze, dated April 2007. As indicatedby Section 5.3.2, there is no single, simple method for quantifying the local contribution to a specific location. In fact, the local component will likely include contributions from more than one sOurce. When applying the model to changesin primary PM2:5, the recommended approach is to identify the individual components of PM2.s. This approach is necessary so that the non-primary components of PM2.s (i.e., nitrates, sulfates, etc.) can be removed and only the primary portions can be considered. For purposes ofthis analysis, only the speciated primary components identified as "soil" and "mixed industrials" were considered. These components should contain most ofthe metals exfi>ected from the steel industry, plus fugitive emissions associated with large industrial areas. Local meteorological (MET)data was used to represent the dispersive nature ofthe southeast Michigan wind patterns. The MET data, collected from the National Weather Service (NWS) at the Detroit Metro Airport, was used forthe local scale analysis. Meteorology data from 2005 was utilized for this analysis. To determine surface characteristics around the Detroit Metro NWS data collection site, the USEPA pre-processorAERSURFACE was utilized. The results from the AERSURFACE program, which were separated by month over 12 sectors, was supplied to the USEPA meteorological pre-processor, AERMET, to create the hourly MET data required by AERMOD. The guidance further recommends that the analysis be done on a quarterly basis. This evaluation deviates from that approach, because most ofthe referenced material was provided on an annual basis. For regional modeling, onereason for performing analyses on a quarterly basis is to account for secondary chemistry variances by season. Since the local scale analysis deals explicitly with primary emissions, seasonal chemistry variances do not apply. Therefore, this deviation from the guidance is not expected to significantly alterthe results ofthis analysis. The methodology used to predict the impacts of required local controls on future PM25 levels was to: 1) model base year (2002) PM2 5 emissions from local point sources to determine the impact on the Dearborn monitor (discussed below); 2) model an attainment year (2009) PM2.5 emissions from Severstal after controls were in place (discussed below); and 3) subtract the controlled attainment year from a nonattainment yearwhen these controls were not in place (20G2-2009=modeled reduction associated with the Severstal controls on the Dearborn monitor).USEPA Dfspersicm Modeling Page 2 

### May 9, 2013

To determine base year local source emissions impacts, the USEPAAERMOD Gaussian Dispersion model was used to predict impacts at the monitors of concern. Due to the proximity ofthe Severstal facility to the monitor, detailed refined modeling used all individual point and volume sources as defined during previous New Source Review permitting. Actual PM25 2002 emissions from Severstal (totaling 553.4 tons/year) were identified by the MDEQ at each detailed emission point. The total modeled impact at the Dearborn monitor is 2.96 1Jg/m3coming from Severstal forthe annual standard, and 17.96 1Jg/m3forthe daily standard. These emissions are considered representative for 2005. To determine the impact of2009 Severstal emissions on the Dearborn monitor, the AERMOD model was run using the 2009 Severstal projected emissions. The emission total is reduced by 148 tons of PM2.5 from the 2002 level because ofthe various controls that the company has installed. Severstal reduced emissions by installing new particulate controls on two blast furnaces, the basic oxygen furnace and several other smaller operations in the facility. The 2009 Severstal impact was predicted by AERMOD to be 1.47 1Jg/m3forthe annual standard, and 9.26 1Jg/m3forthe daily standard. The expected reduction in observed values at the Dearborn monitor in 2009 resulting from reductions at Severstal, is calculated by subtracting the modeled 2009 value for Severstal from the modeled2002 value for Severstai:·The result is apredicted improvementatthe-Dearborn monitorof 1.49 1Jglm3for the annual PM2.5 standard and 8.7 1Jg/m3forthe daily standard. The USEPA CAMX modeling, which did not take into account these local source controls of direct PM2.5 predicted the annual value to be 16.32 1Jg/m3and the daily to be 39.8 1Jg/m3
, which means the annual value would need to be reduced by 1.321Jg/m3to attain the annual NAAQS at 151Jg/m3
, and the 39.8 1Jglrn3would need to be reduced by 4.8 1Jg/m3to attain the daily NAAQS at 35 1Jg/m3

. The modeled reductions in local source contributions to monitored concentrations, when coupled with the larger scale photochemical model (CAMX), would indicate that the area is attaining even without regional controls. Given the magnitude of reductions achieved through permanent and enforceable controls oflocal sources, the MDEQ believes that these local controls have helped bring the area into attainment, and will allowthe area to continue to maintain that attainment. To support this is the fact that the monitored values have been meeting the standards since 2009 forthe annual average and for the 24-hour average, as follows:
Year PM2.5 Annual Average PM2.5 24-Hour Average (>Jg/rn3) (1Jg/m3)

. 2009 14.1 35 2010 12.2 32 2011 11.3 31 2012 11.5 28 AERMOD modeling summary files forthe 2005 and 2009 analyses are available electronically.