DATE: February 7, 2011 FILE REF: 4530 

FID: 744008100 

TO: Joseph Hoch – AM/7 

 Neal Baudhuin – NOR (Rhinelander) 

FROM: John Roth – AM/7 

SUBJECT: Air Dispersion Analysis for Wausau Paper Mills – Rhinelander (Oneida County) 

A. INTRODUCTION 

A dispersion modeling analysis was completed on February 5, 2011 to assess the impact to ambient air of sulfur 

dioxide (SO2) emissions from Wausau Paper Mills in Rhinelander (Oneida County). This analysis was performed in 

support of the technical support document for Oneida County SO2 nonattainment. 

 

B. MODELING ANALYSIS 

• Stack parameters used in this analysis were derived from historical dispersion modeling analyses combined with 

permit allowable emission rates. Building dimensions were determined using BPIP-PRIME with measurements 

taken on plot plans provided by Wausau Paper Mills – Rhinelander (WPMR). Please refer to the source 

parameter table for modeled values. 

• The results from the preliminary modeling analysis were lower than the measured design value from the 

Rhinelander monitor. Since no other sources of SO2 exist in the immediate area, the result from the modeling 

of WPMR should match the measured design value. Further sensitivity tests with other, distant sources, and 

with other meteorological data sets also had modeled impacts less than those monitored. Without having instack emission parameter monitoring, it is uncertain what stack conditions led to the high monitor values. 

Therefore, for this analysis the exit gas temperature and exit gas velocity were adjusted downward until the 

modeled concentration at the receptor nearest the Rhinelander monitor matched the measured design value. 

• Five years (1998-2002) of preprocessed meteorological data was used in this analysis. The surface data was 

collected in Rhinelander (RHI), and the upper air meteorological data originated in Green Bay. 

• The AERMIC (AMS/EPA Regulatory Model Improvement Committee) Model (AERMOD) was also used in 

the analysis. The model used rural dispersion coefficients with the regulatory default options. These allow for 

calm wind and missing data correction, buoyancy induced dispersion, and building downwash including 

recirculation cavity effects. 

• USEPA guidance specifies that the highest hourly measured SO2 value be used for regional background. The 

monitoring data in Wisconsin from 1998-2009 was collected and examined to determine if any sites could serve 

as regional background for Rhinelander. SO2 has generally been monitored near industrial facilities and most of 

the maximum hourly values are very high. Therefore, in this analysis all nearby sources of SO2 will be 

explicitly modeled and a background value from a non-industrial monitoring location will be used. The Forest 

County Potawatomi Community operates a monitor that is ~45km from any major source of SO2, and the 

maximum hourly value from 2007-2009 (39.2 μg/m3

) will serve as the hourly regional background 

concentration. Additional emissions of SO2 will then be input to the model from Red Arrow Foods in 

Rhinelander and Packaging Corporation of America in Tomahawk. 

State of Wisconsin CORRESPONDENCE/MEMORANDUM
C. MODEL RESULTS 

The overall goal of this analysis is to examine the geographic extent of the high SO2 concentrations. While there 

may be some long-distance (greater than 100 km) transport of SO2, it is expected that individual facilities are the 

primary culpable sources. Because of this, the area that experiences concentrations above the standard may be much 

less than the presumed county-wide nonattainment. The results from this dispersion modeling analysis were postprocessed to produce the five-year average of the 99th percentile of the daily maximum concentration. This data was 

entered into a geographic information service (GIS) program to produce the images on the following pages. The 

results shown include the modeled impact plus the estimate of regional background concentration. 

Note that the areal extent shown is defined by the maximum modeled design value concentration at each receptor. 

For any particular hour only a small subset of points is affected, and the locations of the affected points vary 

throughout the day and throughout the year. 

WAUSAU PAPER MILLS - RHINELANDER 

Emission Rates & Stack Parameters 

Stack 

ID 

LOCATION 

(UTM83) 

HEIGHT 

(M) 

DIAM 

(M) 

VELOCITY 

(M/S) 

TEMP 

(K) 

SO2

#/HR 

S08 311338, 5056922 35.66 1.68 20.08 439.0 15.23 

S09 311349, 5056895 63.09 2.13 5.00 345.0 1050.0 

S11 311384, 5056829 60.96 3.35 3.00 400.0 471.5 

Red Arrow Foods Rhinelander Sources 

S07 307577, 5055183 12.56 1.01 14.40 444.3 3.23 

S10 307604, 5055176 15.54 1.07 13.20 366.5 3.23 

PCA Tomahawk Sources 

S14 285952, 5036176 46.60 1.37 4.64 470.4 140.3 

S15 285952, 5036203 60.70 3.23 16.50 468.0 2563.0 
Oneida Forest

Lincoln

Vilas

Langlade

Iron

Price

Taylor

Rhinelan

1-Hour S

Modeling 

City/Village/TowCounty Names

0 10 

5 
PELICAN

PINE LAKE

STELLA

CRESCENT

NEWBOLD

Rhinelander

HARRISON ENTERPRISE

CASSIAN

SUGAR CAMP

KING SC

WOODBORO

LAKE TOMAHAWK

Rhinelan

1-Hour S

Modeling 

City/Village/Town 

03

1.5 
PELICAN

PINE LAKE

STELLA

CRESCENT

NEWBOLD

Rhinelander

HARRISON ENTERPRISE

CASSIAN

SUGAR CAMP

KING SC

WOODBORO

LAKE TOMAHAWK

Rhinelan

1-Hour S

Recepto

> 95% S

City/Village/Town N

03

1.5 
Rhinelan

1-Hour S

Recepto

> 95% S

012 0.5 Miles