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' STATE OF MICHIGAN .,.,~~·--:::····cAE'"1 DEPARTMENT OF ENVIRONMr/KC'drJAl.'i'fY ·' . . . rr -=:....:: . LANSING ·.t'~t ;i,l ·~ 

RICK SNYDER ~-~- ~:il' DAN WYANT 

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, "Request to 

Redesignate to Attainment Status for Both the Annual and 24-Hour PM2.5 

NAAQS". 

The Michigan Department of Environmental Quality (MDEQ), Air Quality Division, is 

.. - pleased !o provide-you with the attached adi:litionaiinformation to supplementthe PM~. 5 redesignation request that was submitted to the United States Environmental Protection 

Agency (US EPA) 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 of controls at a steel-making facility directly impacting the formerly-violating 

PM25air monitor in Dearborn, Michigan, and relates it to photochemical modeling of the 

area performed by the US EPA 

We believe the attached information will satisfy any further concerns you may have with 

the redesignation request, and you will be able to propose approval in the near future. 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 

v ./ . . /...,._. / A ·~?f!:~- . ·'/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 of the 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/m3

) annual reduction in PM2.5 and 8.7 1Jg/m3 daily reductions at the Dearborn monitor as 

a result of the 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 of the total PM25 (i.e., 10 to 30 percent of the 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 of the US EPA Guidance on the Use of Models and Other Analyses for Demonstration 

Attainment of Air Quality Goals for Ozone. PM2 5• and Regional Haze, dated April 2007. 

As indicated by 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 of this analysis, only the speciated primary components identified as 

"soil" and "mixed industrials" were considered. These components should contain most of the 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 of the southeast 

Michigan wind patterns. The MET data, collected from the National Weather Service (NWS) at the 

Detroit Metro Airport, was used for the 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-processor AERSURFACE 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 of the referenced material was provided on an annual 

basis. For regional modeling, one reason 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 alter the results of this 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 year when 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 USEPA AERMOD Gaussian Dispersion 

model was used to predict impacts at the monitors of concern. Due to the proximity of the 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/m3 coming from Severstal for the annual 

standard, and 17.96 1Jg/m3 for the daily standard. These emissions are considered representative for 

2005. 

To determine the impact of 2009 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 of the 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 1.4 7 1Jg/m3 for the annual standard, and 9.26 1Jg/m3 for the 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 a predicted improvement at the-Dearborn monitor of 

1.49 1Jglm3 for the annual PM2.5 standard and 8. 7 1Jg/m3 for the 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/m3 and the daily to be 39.8 1Jg/m3

, which means the 

annual value would need to be reduced by 1.321Jg/m3 to attain the annual NAAQS at 151Jg/m3

, and 

the 39.8 1Jglrn3 would need to be reduced by 4.8 1Jg/m3 to 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 of local 

sources, the MDEQ believes that these local controls have helped bring the area into attainment, 

and will allow the area to continue to maintain that attainment. To support this is the fact that the 

monitored values have been meeting the standards since 2009 for the 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 for the 2005 and 2009 analyses are available electronically.