Appendix K

Analysis of Monitored Concentrations and Wind Direction

Introduction

This document supports the redesignation request for the Campbell-Clermont partial 

nonattainment area in the State of Ohio and the Commonwealth of Kentucky. This 

nonattainment area encompasses emissions from the Walter C. Beckjord facility. There 

are no other significant sources of SO2 emissions within the nonattainment area that 

warrant inclusion in the modeling analysis. As can be seen from the inventory included 

in the redesignation request, the SO2 emissions from the point sources comprise 

99.95% of the 2014 SO2 emissions in the entire nonattainment area. Notably, violations 

at this monitor were determined to be caused by emissions from the Walter C. Beckjord 

facility located along the Ohio River in Ohio east of the monitor. On September 1, 

20141, the Walter C. Beckjord facility ceased operations. Ohio EPA was notified of the 

permanent shutdown on October 14, 2014. (Appendix B and I of the redesignation 

request) There are no other significant point sources of SO2 emissions located in the 

nonattainment area. Within the portion of Campbell County, KY that is a part of this area 

there are 11 sources which combined emit less than one ton per year (tpy) of SO2. 

(Appendix C of the redesignation request) There are no other point sources of SO2

emissions in the portion of Clermont County, OH that is a part of this area. 

Located south (and slightly east) of the monitor, but outside of the nonattainment area, 

is the William H. Zimmer facility (see Figure 1). It was determined during the 

nonattainment designation process that emissions from the William H. Zimmer facility 

likely do not impact the violating monitor at question, and therefore, the nonattainment 

area was not expanded to encompass this facility. To support the previous conclusion, 

Ohio EPA performed an extensive meteorology, emissions and back-trajectory analysis 

and has included this analysis as Appendix D of the redesignation request. This 

analysis concludes that it was in fact the Walter C. Beckjord facility that caused the 

violations and not the William H. Zimmer facility.

In support of this conclusion, Ohio EPA conducted an analysis of hourly SO2

concentrations recorded at monitor 21-037-3002, wind direction data from the Cincinnati 

weather station located at the Cincinnati Northern Kentucky Airport, and emissions from 

both the Walter C. Beckjord and William H. Zimmer facilities for years 2012 through 

February 28, 2015. This time period is henceforth referred to as the study period. The 

analysis presented in this document further demonstrates that emissions from William 

H. Zimmer and other sources within and outside of the nonattainment area are not likely 

to cause exceedances both at the monitor and in the entirety of the nonattainment area 

 

1

The letter contained in Appendix B identifies the permanent shutdown of all units occurred on October 1, 

2014. However, a review of CAMD emissions showed that all the units ceased operation by September 

1, 2014.
and that the shutdown of the Walter C. Beckjord facility will result in attainment of the 

standard.

Methodology

Hourly SO2 emissions data from the Walter C. Beckjord and William H. Zimmer facilities 

were collected from the U.S. EPA Clean Air Markets Database for the study period. 

Hourly and one-minute wind data were collected from the National Weather Service 

station located at the Cincinnati Northern Kentucky Airport. To ensure that the most 

complete meteorological record possible was used, Ohio EPA processed the hourly 

meteorological data and one-minute ASOS data using the most recent versions of the 

AERMOD preprocessors AERMET and AERMINUTE. In addition to eliminating missing 

periods in the meteorological data, this processing provided hourly outputs that were 

more easily paired with hourly emission and monitor data. Hourly monitoring data for 

monitor 21-037-3002 were obtained from U.S. EPA’s Air Quality System.

After compiling the above hourly data, Ohio EPA binned all data based on wind 

direction data, in ten degree increments. This was done for the entirety of the study 

period. The same binning of the data by wind direction was also done for only those 

periods in which the Walter C. Beckjord facility had zero SO2 emissions. This yielded a 

substantial dataset of 10,231 hours monitoring data not impacted by emissions from the 

Walter C. Beckjord facility. It should be noted, however, that no accounting for any 

temporal overlap between any hour of zero emissions from the Walter C. Beckjord 

facility and monitor values was performed. Thus, it is likely that this dataset represents 

some impacts from Walter C. Beckjord at the monitor location. Ohio EPA believes that 

by not accounting for this overlap, any subsequent analysis of this dataset will be 

conservative.

Within each of the above datasets, Ohio EPA determined for each wind direction bin the 

highest and second-highest monitored concentration, the percentage each wind 

direction bin represents to the total, and the number and percentage of monitor values 

of 0 ppb. 

Analysis and Results

To determine the primary wind directions in which monitored concentrations are 

elevated, Ohio EPA evaluated those bins for which either the first or second highest 

monitored value represented an exceedance of the standard. Further, Ohio EPA 

included in its evaluation any bin for which the sum of the first and second highest 

monitored values within that bin exceeded the average plus the sample standard 

deviation of this value, across all bins. For the full study period, which includes impacts 

from the Walter C. Beckjord facility, Ohio EPA determined that winds originating from 

between 31° and 140° and from between 151° and 170° had the greatest impact on 

monitor concentrations. The results of this analysis are consistent with those presented 

in Appendix D of the redesignation request. The maximum concentration recorded at 

the monitor during the study period, 156 ppb, was the result of winds originating 

between 121° and 130°. This result is again consistent with the results presented in 
Appendix D of the redesignation request, which details this exceedance as the February 

20, 2012 exceedance, and is attributed to emissions from the Walter C. Beckjord facility. 

The same binning analysis described above was performed for the dataset compiled 

from hours in which emissions from the Walter C. Beckjord facility were zero. It should 

be noted that this data set of 10,231 hours encompasses 1,445 hours of 2012, 2,542 

hours of 2013, 4,828 hours of 2014, and 1,416 hours of 2015. Additionally, no 

exceedances of the standard were monitored during these hours, and the highest 

maximum hourly concentration recorded during these hours was 34 ppb. Using the 

same procedure as described above, Ohio EPA determined that for this dataset, winds 

originating between 211° and 220°, as well as those originating between 251° and 300°

had the greatest impact on monitor concentrations. This represents a significant shift in 

impacting wind directions with respect to the results of the full study period. Further, 

these wind direction bins resulted in no exceedances at the monitor over the full 2012 to 

February 28, 2015 study period. Ohio EPA contends that this is strong evidence that 

the shutdown of the Walter C. Beckjord facility will result in the attainment of the 

standard both at the monitor and across the entirety of the nonattainment area. This is 

supported by the supplemental modeling and extrapolation analysis described in 

Appendix J of the redesignation request.

The shift in impacting wind directions observed between the datasets is significant, and 

warrants further analysis. Figure 1, below, shows the location of monitor 21-037-3002 

and facilities within a 50 km radius with SO2 emissions greater than or equal to 1,000 

TPY in 2014. 
Figure 1: Facilities within 50 km of monitor 21-037-3002 with 2014 emissions >1,000 tons SO2. 

As stated above, Ohio EPA determined that for the dataset excluding periods when the 

Walter C. Beckjord facility was emitting SO2, winds originating between 211° and 220°, 

as well as those originating between 251° and 300° had the greatest impact on monitor 

concentrations. Figure 1 above suggests that these wind directions would bring 

emissions from the Miami Fort Station, 30.3 km away from the monitor, and from the 

Duke Energy Kentucky East Bend facility, located 35.3 km distant from the monitor. 

Given these large distances, Ohio EPA believes that the impact of these facilities will be 

relatively uniform across the nonattainment area. Dispersion screening tests for Miami 

Fort Station would suggest that over this distance, there would be an approximately 

86% decrease from the point of maximum concentration, located within approximately 1 

km of the facility, to a point 30 km distant, and an 89% decrease at 40 km. This 

indicates that there is little concentration gradient across the nonattainment area 

associated with sources located 30 to 35 km distant. Further, as demonstrated above, 

the highest concentration recorded at the monitor with winds originating from the above 

directions is 34 ppb. Ohio EPA believes that it is highly unlikely that a future 

exceedance of the standard will be observed at the monitor location due to emissions 

from these facilities, and given the significant distances between these facilities and the 

nonattainment area it is unlikely that a significant concentration gradient across the 

nonattainment area from these facilities is present. Additionally, Ohio EPA anticipates a 

further reduction in SO2 emissions from those facilities potentially impacting the monitor 

in the future. 
In 2014, the facilities above emitted 78,349 tons of SO2. The shutdown of the Walter C. 

Beckjord facility, which Ohio EPA has demonstrated in detail is the primary cause of 

monitored exceedances, will result in a 32,603 ton decrease in SO2 emissions. Miami 

Fort Unit 6 (Ohio EPA unit ID B007), an uncontrolled unit, is shutdown as of June 1, 

2016 to comply with the Mercury and Air Toxics Standards. (Appendix L of the 

redesignation request) This will result in a further 18,796 ton reduction from 2014 

levels. In total, this represents a reduction in SO2 emissions of approximately 66% from 

2014 levels. As previously demonstrated, no hourly SO2 values were above the 

standard have been recorded when emissions from the Walter C. Beckjord facility are 

eliminated from analysis, and the highest recorded monitor value across this dataset is 

34 ppb. When this is considered in light of the substantial reduction in SO2 emissions in 

and around the nonattainment area, it is highly unlikely that an exceedance of the 

standard will be monitored in the future, nor is there likely to be a significant 

concentration gradient in the nonattainment area given the significant distances 

between SO2 emission sources and the nonattainment area.

Lastly, Ohio EPA compiled the first through 30th highest hourly monitored SO2

concentrations for all hours during the 2012-February 28, 2015 period for which SO2

emissions from the Walter C. Beckjord facility were zero. These data are presented in 

Table 1, below.

Monitor 21-037-3002

Date Hour Monitor Value (ppb)

January 14, 2015 10 34

September 2, 2013 7 29

January 14, 2015 9 26

January 6, 2015 19 24

September 4, 2013 17 20

January 14, 2015 11 20

May 17, 2013 12 19

August 22, 2014 11 19

January 8, 2015 1 19

September 22, 2012 9 18

September 2, 2014 17 18

January 5, 2015 9 18

January 6, 2015 21 18

September 2, 2013 6 17

January 6, 2015 18 17

August 27, 2014 15 15

January 9, 2015 22 15

January 6, 2015 17 14

January 6, 2015 20 14

January 9, 2015 21 14

September 30, 2012 10 13
May 17, 2013 11 13

November 12, 2014 16 13

January 5, 2015 13 13

January 22, 2015 16 13

September 14, 2012 11 12

October 9, 2013 10 12

October 28, 2014 15 12

September 30, 2012 11 11

May 25, 2013 11 11

Table 1: Highest hourly monitored SO2 concentrations, 2012-February 28, 2015, monitor 21-037-

3002, Walter C. Beckjord impacts removed.

To maintain conservatism, Ohio EPA eliminated monitor values of zero from the 

percentile calculation, giving a total of 2,939 non-zero monitor values for which SO2

emissions from the Walter C. Beckjord facility were zero. Thus, the 99th percentile value 

of these data is the 29th highest hourly value. This value, 11 ppb, was recorded on 

September 30, 2012 and is highlighted in Table 1, above.

Ohio EPA has demonstrated that a significant shift in wind directions which impact 

monitor 21-037-3002 are observed when emissions from the Walter C. Beckjord facility 

are eliminated from hourly wind and monitor data. From amongst this dataset, the 

highest monitor value recorded was 34 ppb, and the 99th percentile of the non-zero 

values is 11 ppb. Further, those sources impacting the monitor in the absence of 

emissions from the Walter C. Beckjord facility are located 30 to 35 km distant from the 

monitor and are therefore unlikely to cause a significant concentration gradient across 

the nonattainment area. Thus, monitor values are considered representative of ambient 

SO2 concentrations across the entire nonattainment area. Additionally, a significant 

reduction in SO2 emissions is anticipated for those sources in and around the 

nonattainment area. Taken together, Ohio EPA contends that the monitor is 

representative of the nonattainment area, that the shutdown of the Walter C. Beckjord 

facility will bring the monitor and nonattainment area into attainment of the standard, 

and that no hourly monitored value for the January 1, 2012 to February 28, 2015 study 

period associated with periods of zero emissions from the Walter C. Beckjord was 

above the standard.