Mr. John Mooney 

United States Environmental Protection Agency 

77 West Jackson Boulevard (AR-18J) 

Chicago, Illinois 60604-3507 

Dear Mr. Mooney: 

I am responding to your October 20, 2015, letter seeking input regarding a request from the 

Sierra Club to designate the area surrounding the DTE Monroe Power Plant as nonattainment 

for the 1-hour sulfur dioxide (S02 ) National Ambient Air Quality Standard (NAAQS). 

The Michigan Department of Environmental Quality (MDEQ) does not agree that the area 

around the DTE Monroe facility should be redesignated as nonattainment, as we detailed in our 

September 18, 2015, submittal to your office requesting the area be designated attainment. The 

modeling analysis submitted by DTE to the MDEQ used the same allowable emission rates as 

provided in their permit and demonstrated attainment with scrubbers installed on all units. As of 

June 2014, scrubbers were operating on all four units. DTE's continuous emissions monitoring 

data, submitted to the Clean Air Markets Division, demonstrates the Monroe plant is meeting 

their allowable limits. 

In the Sierra Club's request letter, their internal modeling includes emissions from DTE Monroe, 

Ohio's Bay Shore Plant, DTE River Rouge, DTE Trenton Channel, Wyandotte Municipal Power 

Plant, and Consumers Energy's JR Whiting plants. Using their listed emission inputs, the Sierra 

Club predicted a pre-background combined impact of 551.6 ug/m3 using allowable emissions 

and 289.9 ug/m3 using actual emissions. 

With the exception of DTE Monroe and Consumers Energy's JR Whiting facility, the modeled 

facilities are outside the DTE Monroe area's significant concentration gradient and do not 

directly impact the area other than within the region's background concentration. The Sierra 

Club's own modeling results also demonstrate virtually all contributions to maximum impacts are 

from DTE Monroe and Consumers Energy's JR Whiting plant. 

The Sierra Club's analysis has serious flaws because the modeled emission rates are 

antiquated and no longer representative. The modeled emissions from all facilities do not reflect 

most recent permits, fuel switches, and shutdowns. 

The Sierra Club's analysis for the facilities that directly contribute to the Monroe area, i.e., DTE 

Monroe and Consumers Energy's JR Whiting plant, contained the following flaws: 

DTE Monroe: The Sierra Club modeled 2462.6 pounds per hour (pph) per unit (i.e., Unit 1 -

Unit 4 ). These emissions do not account for the scrubbers recently installed on all four units. 

All scrubbers were in place by June 2014. The new permitted allowable emission rates are 

815.8 pph per unit. New Source Review modeling showed compliance with the 1-hour S02 

NAAQS using these allowable emission rates. 

CONSTITUTION HALL • 525 WEST ALLEGAN STREET • P.O. BOX 30473 • LANSING, MICHIGAN 48909-7973 

www.michigan.gov/deq • (800) 662-9278 
modeled 6,400 pph (i.e., 28,032 tons per year (tpy)), which will be entirely eliminated. 

The 2014 emissions inventory indicates total facility emissions have already been 

reduced to 6,439 tpy. 

In summary, each facility included in the Sierra Club's analysis has either installed 

controls, reduced emissions, switched fuels, has or will shut down, or is appropriately 

included in the area's background concentration. This leads to the obvious conclusion that 

the predicted impacts supporting the Sierra Club's Monroe area designation petition are 

severely over-estimated. Further, the air monitor installed in the proximity of the predicted 

DTE Monroe hotspot at Sterling State Park, shows ambient concentrations well below the 

75 parts per billion (ppb) threshold. The 2013-2015 (to date) monitor data show a design 

value of 17.5 ppb. 

If you have any questions regarding this issue, you may contact Mr. Robert Irvine, AQD, at 

517-284-6749; irviner@michigan.gov; MDEQ AQD, P.O. Box 30260, Lansing, Michigan, 

48909-7760; or you may contact me. 

Sincerely, 

cc: Mr. Robert Irvine, MDEQ 

CONSTITUTION HALL • 525 WEST ALLEGAN STREET • P.O. BOX 30473 • LANSING, MICHIGAN 48909-7973 

www.michi9an.gov/deq • (800) 662-9278