# Cache Valley Idaho

PM 2.5 

# Nonattainment Area State Implementation Plan Amendment

State of Idaho Department of Environmental Quality

December 2014Printed on recycled paper, DEQ

, December 2014

, PID CVSP

, CA 61 215 . Costs associated with this publication are available from the State of Idaho Department of Environmental Quality in accordance with Section 60

- 202, Idaho Code.

# Cache Valley Idaho

PM 2.5 

# Nonattainment Area State Implementation Plan Amendment

December 201 4

Prepared by Idaho Department of Environmental Quality

Pocatello Regional Office 444 Hospital Way, #300 Pocatello , Idaho 83201This page intentionally left blank for correct double-sided printing.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

iii 

### Table of Contents

Acronyms, Abbreviations, and Symbols ................................................................

........................ v 1 Introduction ................................

................................................................ .............................. 1
2 Air Quality Data ................................

................................................................ ...................... 2
2.1 Idaho and Utah Summary ................................................................

................................ . 2
2.2 Design Value Determination- 24-Hour Standard ................................

............................. 4
3 Meteorological Discussion ................................................................

................................ ...... 4
4 Emissions and Attainment Year Inventories ................................................................

........... 6 5 Modeled Attainment Test and Attainment Date ................................

................................ ...... 6
6 Control Strategies ................................

................................................................ .................... 7
6.1 Reasonably Available Control Measures

................................................................ ......... 8
6.2 Reasonably Available Control Technology ................................

................................ ...... 8
6.3 Additional Emissions Reductions (Woodstove Change Out) ................................

.......... 8
6.4 Voluntary Measure

— Dairy Rule ................................................................

..................... 9
7 Conclusion ................................

................................................................ ............................... 9
8 References ................................

................................................................ .............................. 10 Appendix A. Meteorological Discussion of the January 2013 Stagnation Episode ................... A-1 Appendix B. Updated Road Sanding Agreements ................................................................

...... B-1 Appendix C. Woodstove Change Outs ................................................................

....................... C-1 Appendix D. Public Involvement ................................................................

............................... D-1



### List of Figures

Figure 1. The 98th percentile of Franklin County, Idaho, 24-hour PM 2.5 values from 2004

– 2013.

................................ ................................................................ ................................ . 3 Figure 2. The 98th percentile of Cache County, Utah, 24-hour PM 2.5 values from 2004

– 2013.

.... 3 Figure 3. Cache County (Logan monitor) running 24-hour PM 2.5 design values. .......................... 4 Figure 4. Cache County, Utah, emissions inventory and annual exceedances (UDAQ 2014). ...... 5 Figure 5. Model results for the Cache Valley nonattainment area, Logan monitor. ....................... 7



### List of Tables

Table 1. Cache Valley emissions inventory (tons per day) for the 2010 base year and 2015 attainment year for PM 2.5, NO x , VOC, NH 3 , and SO 2 ; emissions shown are for Utah and Idaho. ................................

................................................................ ......................... 6 Table 2. Modeled concentrations for the Cache Valley nonattainment area. ................................ 7 Table 3. Emissions reductions due to the woodstove change outs. ................................

................ 8Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

iv This page intentionally left blank for correct double-sided printing.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

v 

## Acronyms, Abbreviations, and Symbols

μg/m 3 micrograms p er cubic meter

ADT average daily traffic

ATR automatic traffic counters

BMP b est management practice

CAA Clean Air Act
CFR Code of Federal Regulations
CMAQ community multiscale air quality model

CO carbon monoxide
CVNAA Cache Valley n onattainment area
DEQ Idaho Department of Environmental Quality
DSL deep stable layer

DV design value

EPA US Environmental Protection Agency

FR Federal Register

HDD heating degree days

IDAPA Idaho Administrative Procedures Act

MATS Model Attainment Test Software

MOVES motor vehicle emission simulator

NAA n onattainment area
NAAQS National Ambient Air Quality Standards

NH 3 ammonia

NO x n itrogen o xides
PBR p ermit by rule

PM particulate matter

PM 2.5 p articulate matter under 2.5 microns in size

PM 10 p articulate matter under 10 microns in sizeCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

vi RWC residential wood combustion

SIP state implementation p lan

SO 2 sulfur d ioxide
tpd tons per day

tpy tons per y ear UDAQ Utah Division of Air Quality

VOC volatile organic compounds

VMT vehicle miles traveledCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

1 

## 1 Introduction

The purpose of th is amendment is to revise the Cache Valley Idaho PM 2.5 Nonattainment Area State Implementation Plan (DEQ 2012 ) to address the Clean Air Act (CAA) Title I, Part D, Subpart 4 requirements. In amending the state implementation plan (SIP ), the following changes occurred:
Revised model attainment test  Revised attainment date  Shifted model base year to 2010  Add ed emissions reductions through additional woodstove change ou ts  S tre ngthen ed the existing road sanding agreements  Provided a voluntary control measure : p ermit by rule (PBR) for dairies, IDAPA  58.01.01.760

– 764

, prescribing best management practices (BMPs) to control ammonia (NH 3 ) and volatile organic compounds ( VOCs ).

This amendment demonstrates that the Cache Valley 2012 particulate matter 2.5 ( PM 2.5 ) SIP satisfies federal PM 2.5 SIP requirements under CAA, Title I, Part D, Subpart 4, attaining the standard by 2015. 

### Background

The Idaho Department of Environmental Quality (DEQ) completed a PM 2.5 SIP for the Idaho side of Cache Valley, which is part of the Cache Valley nonattainment area (CVNAA) (Logan UT-ID NAA), and submitted it to the US Environmental Protection Agency ( EPA ) in December 2012. This plan satisfied requir ements from EPA’s 200 7 Fine Particle Implementation Rule, which was grounded in the CAA, Title I, Part D, Subpart 1.
On January 4, 2013, the District of Columbia Circuit Court found that EPA incorrectly interpreted the CAA when determining how to implement the National Ambient Air Quality Standards (NAAQS) for PM 2.5 . The court ruling held that the EPA should have implemented the PM 2.5 NAAQS based on both CAA, Title I, Part D “Plan Requirements for Nonattainment Areas,” Subpart 1 “Nonattainment Area s in Gene ral” and Subpart 4 “Additional Provisions for Particulate Matter Nonattainment .” Therefore, as of January 4, 2013, Subpart 4 also applies.

Under CAA Subpart 4, nonattainment areas (NAAs) for particulate matter may carry the classification of either moderate or serious. Subpart 4 address the attainment dates and planning provisions for both moderate and serious particulate matter NAAs. The Logan UT-ID NAA is classified as a moderate PM 2.5 NAA.
Since its submission in December 2012, EPA acted on two portions of the Cache Valley, Idaho, PM 2.5 SIP (DEQ 2012)

. In March 2014, EPA issued a Federal Register (FR) notice finalizing a limited approval of PM 2.5 control measures contained in the December 2012 submittal because incorporation of these measures strengthen the Idaho SIP and reduce sources of PM 2.5 emissions in Franklin County that contribute to violations of the 2006 PM 2.5 standard on the Idaho side of the Logan UT-ID NAA (79 FR 16201 [March 25, 2014]). In July 2014 , EPA issued an FR noticeCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

2 approving the baseline emissions inventory contained in DEQ’s submittal as meeting the requirement to submit a comprehensive, accurate, and current inventory of direct PM 2.5 and PM 2.5 precursor emissions in Franklin County (79 FR 41904 [July 18, 2014 ] ).
The amendment addressing Subpart 4 is required to be submitted by December 31, 2014, and demonstrate attainment by December 31, 2015.

For additional information, refer to the Cache Valley Idaho PM 2.5 Nonattainment Area State Implementation Plan ” (DEQ 2 012), which is available at www.deq.idaho.gov/media/930589- cache_valley_pm2_5_nonattainment_state_implementation_plan_1212.pdf. The SIP appendices are available at www.deq.idaho.gov/media/930593-cache-valley-pm2-5 -sip-appendices -1212.pdf.



## 2 Air Quality Data

PM 2.5 standards are based on averaging air quality measurements both annually and on a 24-hour basis. The 24 -h ou r standard is designed to provide an appropriate level of protection from shortterm exposures to PM 2.5
. The 24 -hour standard for PM 2.5 is met whenever the 3-year average of the annual 98th percentile of values at designated monitoring sites in an area is less than or equal to 35 micrograms per cubic meter (μg/m 3 ). The analysis of the PM 2.5 data for the monitoring sites across the valley show violations of the 24-hour PM 2.5 NA AQS on both the Utah and Idaho sides of the CVNAA.



### 2.1 Idaho and Utah Summary

Figure 1 details the 98 th percentile monitoring data for the Franklin County, Idaho, air quality monitor from 2004 through 2013. The 2010 data should not be considered representative of the area; due to upgrades to the Franklin sewage lagoons, the area was without power for a considerable portion of the year. During 2010, none of the quarters for data collection met EPA criteria for data completeness. Figure 2 details the 98 th percentile monitoring data for the Cache County, Utah air quality monitor.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

3 Figure 1

. The 98th percentile of Franklin County, Idaho, 24 -hour PM 2.5 values from 2004–2013.

Figure 2. The 98th percentile of Cache County, Utah, 24 -hour PM 2.5 values from 2004–2013.

0 20 40 60 80 100 120

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013concentration(micrograms per cubic meter)

year



## 98th Percentile of Franklin County 24

- hr PM 2.5 

## Values

*

0 20 40 60 80 100 120

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013concentration(micrograms per cubic meter)

year



## 98th Percentile of Cache County 

# 24

- hr PM 2.5 

# ValuesCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

4 

### 2.2 Design Value Determination— 24 -Hour Standard

Design values are the metrics that are compared to the NAAQS to determine compliance. For the 24 -h our standard, the design value is the 3-year average of annual 98 th percentile, 24-h ou r average values. The 24-hou r PM 2.5 NAAQS is met when the design value is less than or equal to 35 μg/m 3

. EPA recommends an average of three such 3 -year averages that straddle the baseline inventory be used to calculate the monitored baseline value. The year 2010 represents the baseline inventory. Therefore, the 3 -year running average of 98 th percentile values collected from 2008

– 2010 would be averaged together with the 3 -year averages from 2009

– 2011 and 2010

– 2012 to arrive at the site-specific monitored baseline design value.
For this SIP, the baseline design value concentration for the Utah side of Cache Valley is 40.7 μg/m 3 . The SIP demonstration will be based on the Utah design value because it is the highest in the CV NAA. The 24 -h ou r PM 2.5 design values for the Cache County (Logan) monitor are shown in Figure 3

.

Figure 3. Cache County (Logan monitor) running 24-hour PM 2.5 design values.



## 3 Meteorological Discussion

The 2012 Cache Valley UT-ID SIP was projected to achieve compliance with the PM 2.5 24 -hour NAAQS by the end of 2014. Projected emissions levels and the number of measured exceedances were trending downward, as indicated in Figure 4 (UDAQ 2014) and the attainment plan appeared to be on track. In 2013, especially in January, the number of exceedances

0 10 20 30 40 50 60 70

2004-2006 2005-2007 2006-2008 2007-2009 2008-2010 2009-2011 2010-201224-hour Design Value(micrograms per cubic meter)

Years 

## Cache County (Logan monitor)Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

5 increased dramatically. DEQ analyzed the January

– February stagnation episodes in an effort to determine whether this was due to suddenly increasing emissions or strictly an unusual weather pattern.
The DEQ analysis, provided in Appendix A, found the following: An unusually strong and persistent high-pressure system occurred in 2013 producing the  coldest January in over 62 years. Baseline source activity related to population and traffic remained approximately flat  from the SIP baseline year, 2010 through 2013. The cold temperatures alone probably exacerbated the emissions by increasing heating  loads and vehicle emission rates (but not source activity). The PM 2.5 concentrations in Cache Valley and other locations in the northwest such as  Boise, Idaho, reached extreme levels as a result not so much of the strength of the inversion, but its persistence, or more specifically the number of consecutive days when the lower stable layer (< 500 meters) did not break up in the afternoon, allowing PM 2.5 and its precursors to accumulate from day to day.
The duration of the January accumulation period was longer than any in at least the past decade. As a result of this analysis, DEQ concluded that the increased exceedances resulted solely from this extreme meteorological event.

Figure 4. Cache County, Utah, emissions inventory and annual e xceed ances (UDAQ 2014).Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

6 

## 4 Emissions and Attainment Year Inventories

A detailed emissions inventory using the best information available was prepared for the Cache Valley airshed to assess direct PM 2.5 emissions as well as emissions of precursors to secondary PM 2.5 formation. In July 2014, EPA issued an FR notice approving the baseline emissions inventory contained in DEQ’s submittal as meeting the requirement to submit a comprehensive, accurate, and current inventory of direct PM 2.5 and PM 2.5 precursor emissions in Franklin County (79 FR 41904 [July 18, 2014] ).

Table 1 lists total daily winter emissions (for both Utah and Idaho) for the 2010 base year as well as the 2015 attainment year. The attainment year totals include projections concerning growth in population, vehicle miles traveled, and the economy. The totals also include the effects of emissions control strategies that are either already promulgated or were required as part of the Utah SIP.

Table 1

. Cache Valley emissions inventory (tons per day) for the 2010 base year and 2015 attainment year for PM 2.5, NO x , VOC, NH 3 , and SO 2 ; emissions shown are for Utah and Idaho.

Notes : particulate matter 2.5 (PM 2.5 ); nitrogen oxides (NO x ); volatile organic compounds (VOC); ammonia (NH 3 ); sulfur dioxide (SO 2 ); tons per day (tpd).



## 5 Modeled Attainment Test and Attainment Date

The Utah Division of Air Quality ( UDAQ ) used the Model Attainment Test Software (MATS) for the modeled attainment test at grid cells near monitors. MATS results for future year modeling at the Logan monitor site are presented in Figure 5 . The future year design value is presented for 2015, the attainment year, along with the MATS future year design values for modeling simulation that include control strategies. For comparison purposes, the monitored design value is also presented for the base year, 2010. Table 2 presents the same information in tabular form and also includes data from the monitoring location in Franklin, Idaho.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

7 Figure 5. Model results for the Cache Valley nonattainment area, Logan monitor.

Table 2. Modeled concentrations for the Cache Valley nonattainment area.

2010 2015
Observed ( μ g/m 3 ) Business

- As

- Usual ( μ g/m 3 ) Control Basket ( μ g/m 3 ) Logan 41 37 34
Franklin 39 34 32

The attainment date for this moderate PM 2.5 N AA is December 31, 2015. As shown in the modeled attainment test, the emissions reductions achievable in 2015 allow for a demonstration that the CV NAA can attain the 24-hour PM 2.5 NAAQS by the attainment date.


## 6 Control Strategies

The overall strategy for improving air quality throughout the Cache Valley consists of many different components across the multistate NAA . Collectively, these components are responsible for reducing PM 2.5 emissions in the CVNAA and have contributed to the demonstration of attainment with the NAAQS by December 31, 2015. Both sides of the Cache Valley (Utah and Idaho) dealt separately with various control measures, due to both jurisdictional authority and differences in the emissions inventory. Details concerning the control measures u sed on the Utah side of the Cache Valley are found in the PM 2.5 SIP and technical supp ort d ocument developed

41

37
34

0 5 10 15 20 25 30 35 40 45

2010 base year 2015, no additional controls 2015, with Utah

control strategiesmicrograms per cubic meter 

### Logan MonitorCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

8 by UDAQ (2014). The following subsection s deal directly with any updates to the existing controls and applicability to CAA, Subpart 4.



### 6.1 Reasonably Available Control Measures

Reasonably available control measures, which refers to measures of any type that may be applicable to a wide range of sources (mobile, area, or stationary), was addressed in the original SIP submission with road sanding agreements and residential wood combustion ordinances. The original road sanding agreements lacked a measure of enforceability. This amendment contains updated road sanding agreements (Appendix B), which are now tied to the IDAPA rules and have a new measure of enforceability.



### 6.2 Reasonably Available Control Technology

Reasonably available control technology refers to measures specifically designed for stationary sources. In developing the emissions inventories underlying the SIP, the criteria of 40 CFR 51 for air emissions reporting requirements was used to establish a 100 tons per year (tpy) threshold for identifying stationary point sources. For the CVNAA, there are no point sources with the potential to emit 100 tpy of PM 2.5 or any PM 2.5 plan precursor.



### 6.3 Additional Emissions Reductions (Woodstove Change Out)

DEQ has operated three woodstove change-out programs on the Idaho side of the CVNAA (2006

– 20 07 , 2011

– 20 12, and 2013

– 20 14), changing out a total of 209 uncertified residential wood combustion devices. The original SIP submission claimed credit for the first two change outs (152 woodstoves). DEQ is claiming credit for the additional 57 wood stoves, as well as an additional 39 uncertified woodstoves that were recycled in accordance with Idaho’s Alternative Energy Device tax deduction. This program allows Idaho citizens to deduct all, or most, of the cost to acquire and install a certified appliance (wood/pellet/gas). Table 3 lists the emissions reductions due to all of the woodstove change outs. Supporting documentation is found in Appendix C. In addition to reductions in particulate matter, the woodstove change-out program has also led to the reduction in air toxics, such as formaldehyde, Acrolein, and benzo(a)pyrene, which are generated as by-products of combustion.

Table 3. Emissions reductions due to the woodstove change outs.

Pollutant Old W oodstove to Cert ified W ood or Gas Stove ( tpy ) Old Woodstove to Pellet Stove ( tpy ) Total (tpy)

CO 46.64 15.72 62.36
SO 2 0.05 0.01 0.06
NO X 0.45 0.02 0.47
VOC 14.79 3.79 18.57
PM 2.5 primary 6.00 2.04 8.04
PM 10 primary 6.00 2.04 8.04
Notes : tons per year ( tpy ), carbon monoxide (CO), sulfur dioxide (SO 2 ), nitrogen oxides (NO x ), vol a tile organic compounds (VOC), particulate matter (PM 2.5 , 10 ).Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

9 

### 6.4 Voluntary Measure—Dairy Rule

DEQ has added an additional voluntary control measure to this SIP amendment to address the control of ammonia emissions in Idaho. Rules for the control of ammonia from dairy farms, IDAPA 58.01.01.760

– 764

, sets forth BMPs for dairy farms of a certain size licensed by the Idaho State Department of Agriculture through a PBR. The PBR applies to dairy farms with a capacity to produce 100 or more tons of ammonia emissions per year. Dairy farms with fewer than the specified number of animal units or mature cows may opt into the PBR program as well.
These rules derived from negotiations amongst the d airy industry, Idaho Department of Agriculture, Idaho Conservation League, and DEQ as part of a settlement of a lawsuit. The stakeholders agreed these rules would not be submitted to EPA for SIP approval. These rules are considered “State Only” rules and are not enforceable by the federal government.
The capacity to produce is based on the number of animal units or mature cows and the type of manure collection system. It requires dairy farms above specified threshold numbers of cows or animal units to register with DEQ and to implement industry BMPs to control ammonia emissions. The BMPs also have the added benefit of controlling VOC emissions. The rules prescribe various BMPs to control ammonia emissions, such as installing certain types of waste storage and treatment systems, implementing composting practices, and exporting manure. A point value is assigned to each BMP. Dairy farms must employ BMPs totaling 27 points.
While model runs have shown that significant reductions in the NH 3 inventories have little to no effect on predicted PM 2.5 concentrations, it was determined that VOCs do play a role in the secondary aerosol formation. This amendment provides for a voluntary control measure: PBR for dairies, IDAPA 58.01.01.760

– 765

, prescribing BMPs to control NH 3 and VOCs. The reduction in NH 3 will likely have no effect on the PM 2.5 formation, but the reduction in VOC is an added benefit that

will help to reduce PM 2.5 secondary aerosol formation.



## 7 Conclusion

This SIP amendment demonstrates that the Logan, UT- ID NAA will achieve attainment with the 24 -hour PM 2.5 NAAQS by December 2015. Utah and Idaho have worked cooperatively with each other, EPA, and citizens to develop control strategies in keeping with the inventories on both sides of the valley. The State of Idaho will continue to monitor PM 2.5 concentrations in Franklin County. If exceedances occur, Idaho will determine the cause(s) and adjust the appropriate control measures to ensure prompt corrective action is taken.
This plan fulfills the requirements of the CAA as they pertain to SIPs. Input received from the public comment period is provided in Appendix D. DEQ requests that EPA approve this attainment plan in accordance with CAA Section 110 and Subpart 4.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

10 

## 8 References

DEQ (Idaho Department of Environmental Quality). 20 12

. Cache Valley PM 2.5 Nonattainment Area State Implementation Plan. Pocatello, ID: DEQ.
FR (Federal Register). 2014. “Revision to the Idaho State Implementation Plan: Approval of Fine Particulate Matter Control Measures; Franklin County.” 79 FR 16201

. FR (Federal Register). 2014. “Approval and Promulgation of Implementation Plans; Idaho Franklin County Portion of the Logan Nonattainment Area; Fine Particulate Matter Emissions Inventory.” 79 FR 41904.

IDAPA. 2014. “Rules for the Control of Air Pollution in Idaho.” Idaho Administrative Code IDAPA 58.01.01.
US Congress. 1970. Clean Air Act. 42 USC § 7401 et seq.

UDAQ (Utah Division of Air Quality). 20 14. PM 2.5 State Implementation Plan, Weight of Evidence in the Model Attainment Test

. Salt Lake City, UT: UDAQ.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A-1 

## Appendix A. Meteorological Discussion of the January 2013

Stagnation EpisodeCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A-2 This page intentionally left blank for correct double-sided printing.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A-3 

## Meteorological Discussion of the January 2013 Stagnation Episode

1 Introduction

The 2012 Cache Valley Utah-Idaho state implementation p lan (SIP) demonstrated that a number of control measures should bring the 24-hour averaged particulate matter 2.5 ( PM 2.5 ) d esign

v alue (DV) concentration under 35 micrograms per cubic meter (μg/m 3 ) and thereby into compliance with the National Ambient Air Quality Standard (NAAQS) by 2015 (DEQ 2012). Emissions were projected to decline and by 2012, there were no exceedances recorded in either Franklin or Cache Counties. However, in 2013, there were numerous exceedances, and the 98 th percentile values were 68 μg/m 3 in Cache Co unty and 55 μg/m 3 in Franklin Co unty. An unusually persistent series of cold temperatures occurred in January

– February 2013, resulting in a sharp increase in the DV, defined as the 95 th percentile 24-hour concentration value averaged over 3 years. The purpose of this analysis is to show that the 2013 increase in PM 2.5 , particularly in January, resulted from an extreme weather pattern and does not represent a sudden reversal of the downward trending emissions rates produced by source control measures as demonstrated in the SIP. To be clear, stagnation events cannot be excluded under the Exceptional Events Rule and such a demonstration is not proposed here, nevertheless, it is of value to understand that the increased 2013 PM 2.5 was strictly the result of an extreme meteorological phenomenon and doe s not indicate that sources are increasing or that the SIP control measures are not working.
The analyses in the following sections will show that:
Section 2. An unusually strong and persistent high pressure ridge remained in place for most of January leading to a very long period of cold air pooling and temperature inversions that persisted throughout each afternoon.
Section 3. Baseline source activity, at least for the major categories re lated to population and traffic, did not suddenly increase in January 2013.
Section 4. While emissions activity (related to population and traffic) itself did not increase, and wood-burning curtailment was in effect for 20 days in January 2013, the coldest January in 62 years probably led to higher than normal home heating emissions and vehicle emission, which contributed to the PM 2.5 buildup.
Section 5. While the inversion conditions were strong, the unusually high PM 2.5 levels resultedprimarily from the duration of the event, or more specifically to the number of days that the lowlevel inversions persisted in the afternoon without breakup. This caused a consistent day- to -day accumulation of PM 2.5 concentrations around 13 μg/m 3 per day. The duration of the continuous low stable layer ( LSL ) period was the longest in at least the past 10 years.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A-4 

## 2 Unusually Strong and Persistent High Pressure System Affected the Region

While no strong direct relationship exists between PM 2.5 levels and the strength of an upper level ridge pattern, the weather characteristics typical to a long-duration upper level ridge event typically enhance PM 2.5 levels. Large -scale synoptic (O: 1, 000 k ilo meter) blocking patterns can be identified by viewing upper level atmospheric observational data as shown in Figure 1. Additional 500 millibar ( mb ) charts for the most severe inversion days are shown in Attachment A. Blocking patterns

— events that limit the zonal motion of passing waves through the atmosphere

— are identified in the analysis below at the 500 mb level, which typically occurs at an elevation of 18,000 f ee t. The two meteorological parameters investigated are the 500 mb heights (the altitude at which 500 mb of pressure occurs) and the 500 mb temperature.
Characteristically, the high pressure blocking patterns that occurred in the month of January 2013 have warmer than normal temperatures and higher than normal heights. Both of these attributes occurred during the period of interest. Again, it must be stressed that while the values of these meteorological parameters share no significant direct relationship to PM 2.5 levels, the weather associated with high pressure blocking patterns can cause increased levels of PM 2.5 with increasing duration of blocking patterns.
Up per air radiosonde profiles from weather balloons for Salt Lake City, Utah, and Boise, Idaho, were obtained to investigate the January 2013 stagnation period in comparison to the 30-year climatology period of 1981

– 2010. Data presented in Table 1 and Table 2 verify that the 500 mb heights were at a statistically significantly higher altitude than climatology (1981

– 2010) for southern Idaho and northern Utah. Boise data during the time periods of January 1

– 6, 2013

, January 15

– 21 , 2013 , and January 15

– 26, 2013

, were each statistically different than the climatological comparison period (Table 1). T- tests (computed with α = 0.05) are shown, such that any T-test value less than 0.05 indicates that the heights and temperatures are statistically different than the 30 -year climatological record of 500 mb heights and temperature. As a result, Boise PM 2.5 concentrations reached their three highest wintertime values since before 1999 on January 19, 22, and 25. This is further indication of the regional nature of the event and that it did not result from any local change in source activity.
Furthermore, published literature has suggested that the heights experienced in the eastern Pacific Ocean and Pacific Northwest were higher than any recorded levels, further promoting theregional scale of this particular wintertime event; in fact, Swain et al. (2014) note that the largescale meteorological pattern over the northeastern Pacific led to observationally unprecedented geopotential heights (an altitude referenced to sea level) over a broad region and noted that this pattern was nicknamed the “Ridiculously Resilient Ridge

. ” Funk et al. (2014), Swain et al. (2014), and Wang and Schubert (2014) all note the role of increasing global temperatures and the increase in frequency of such highly anomalous ridge events over the eastern Pacific and Pacific Northwest in the future. Finally, while noted for the relationship between geopotential height and precipitation, the probability of an event with such high anomalies was determined to be less than 1 in 126 years (with confidence > 95%). Al though this relationship was discerned with precipitation in mind, it serves to indicate the general strength and anomalous nature of the January 2013 event.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A-5 Figure 1. The 500 mb height contours for January 2, 2013, showing a Rex block high pressure ridge over the Pacific Northwest.
Table 1. Paired T-test values and anomalies for periods of interest for Boise, Idaho. a
Boise α=0.05 α=0.05 Height Anomaly (m) Temperature

Anomaly ( o C) Date T

- test Value

Height T

- test Value

Temp ( o C)
Entire month b 0.26005 0.23740 29.26 29.26 January 1

– 6 0.00708 0.00335 91.02 3.63 January 15

– 21 0.00008 0.00027 155.90 4.78 January 15

– 26 <0.00001 <0.00001 137.99 5.10

a. Compared to 1981

– 2010 climatology

. b. January 30, 2013, values are averaged from January 29 and 31.
In Salt Lake City, the time periods of January 15

– 21, 2013

, and January 15

– 26, 2013

, are also significantly different than climatology for those dates (Table 2). One can see that the 500 mb heights were typically 90

– 150 meters higher than climatology at Boise and Salt Lake City for those time periods. As is typical with ridge patterns, the 500 mb temperature ( o C) was also higher than climatology over the same times with the same events being statistically significant for Boise and Salt Lake City as with the 500 mb height. The 500 mb temperature anomalies varied from 3.5 o C to 5.1 o C higher than climatology. It is important to note that the data do not indicate the relative intensity or strength of the corresponding high or low pressure systems as the data are single-point values from two locations.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A-6 Table 2. Paired T-test values and anomalies for periods of interest for Salt Lake City, Utah. Salt Lake City α=0.05 α=0.05 Height Anomaly (m eters ) T emperature

Anomaly ( o C) Date T

- test Value

Height T

- test Value

Temp ( o C )
Entire m onth 0.90839 0.99719 2.94 0.00 January 1

– 6 0.39089 0.23215 30.60 1.41 January 15

– 21 0.01859 0.00958 101.28 3.55 January 15

– 26 0.00021 0.00007 111.05 4.56
Note : Compared to 1981

– 2010 c limatology

. 

## 3 Major Sources of PM 2.5 

## and Precursor Emissions D id Not Increase in 2013

When ambient concentrations of a pollutant increase, one must consider two contributing factors: (1 ) sources are increasing, or (2 ) weather is causing the pollutants to be more concentrated over more days. To evaluate the first factor, DEQ considered the largest source categories of PM 2.5 and its precursors that cause increased PM 2.5 formation in the Cache Valley atmosphere

— area sources such as home heating and traffic. Both traffic and home heating, including residential wood combustion, are major sources of PM 2.5 and PM 2.5 precursors : nitrogen oxides (NOx) and

v olatile organic compounds (VOCs). (Ammonia is a PM 2.5 precursor but is believed to be so abundant that moderate changes in ammonia levels have little effect in the Cache Valley wintertime atmosphere.) Population and traffic counts were selected to represent the source activity for home heating and other area sources, and for traffic. The changes from 2010, the baseline year of the Utah Division of Air Quality ( UDAQ ) SIP

, and 2013 are shown in Table 3.


### 3.1 Traffic

Traffic counts for the four automatic traffic counters (ATRs) in Cache Valley on main roads and with a record back to 2004 were obtained from the Utah Department of Transportation (UDOT 2014). A sum of the January weekday average daily traffic (ADT) counts at three primary ATRs in Cache County with a continuous record back to 2004, as well as the ATR on State Road 91 at the Idaho-Utah border, is shown in Figure 2 for the period from 2004 to 2013. The traffic sum in 2013 is within 1% of the values in 2004 and represents a 2

. 7% decrease from 2010 (Table 3). Thus both the traffic activity (or vehicle miles traveled [VMT]) in Cache County, Utah, and that entering Cache County from Franklin County, Idaho, is generally flat and is clearly decreasing from 2010 to 2013. This finding only relates to VMT or traffic activity, however, it should be noted that vehicle emission rates (per VMT) are declining every year as a result of new car emission standards, and the inspection and maintenance program will begin to lower emission rates as well.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A-7 Figure 2. Weekday a ve rage daily traffic counts summed for 3 ATRs (363, 510, 511) in Cache County, and one ATR (303) on State Road-91 at the Utah-Idaho border showing a flat 10 -year trend and slight reducti on from the 2010 SIP baseline year to 2013. 

### 3.2 Population

As shown in Table 3, the population in Cache County, Utah, grew only 3.8% from April 2010 to July 2013, while Franklin County, Idaho, grew only 0.5% (US Census Bureau 2014). Population represents a surrogate for most area sources, including wintertime home heating sources, a major contributor of NOx, VOCs, and PM 2.5
. Thus, we must conclude that the area source categories that vary with population, including residential wood combustion, other combustion home heating sources, residential outdoor burning, and consumer uses of VOC-containing products like solvents and paints do not appear to account for any significant increase in air pollution during January

– February 2013. If the source activities cannot explain the increase in PM 2.5 for this period, we must look to the weather to see if an explanation of the high pollution levels can be found.

Table 3. Changes from 2010 to 2013 in a rea source activity, represented by population and tr affic for Cache County
, Utah, and Franklin County, Idaho, from 2010 to 2013.

Cache Co unty , Utah Franklin County
, Idaho Population 3.80% 0.50%
Traffic

- 2.7%

- 4.6%Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A-8 

## 4 Unusually C old Temperatures Exacerbated Heating and Vehicle Emissions

The discussion about source activity levels in section 3 demonstrates that changes in the population and traffic activity levels were minor suggesting that residential home heating and traffic emissions alone could not explain the very large increase in concentration. In addition, mandatory curtailment burn bans were in effect on 20 of the inversion episode days in January 2013

, which should have lowered residential wood combustion and residential open burning activities significantly. Nevertheless, the cold temperatures alone probably enhanced emissions from heating and vehicles and may have negated some of the emission-lowering benefits of the burn bans.
As a corollary to the extremely cold temperatures in Cache Valley during January 2013, the heating degree days (HDD) in January 2013 were the highest of any January in the previous 62 years. The mean HDDs in Logan (WRCC 2014) are shown in Figure 3 along with their 95% confidence intervals, minimum and maximum values, and the 2013 values (green circles). Since residential wood combustion (and all other types of home heating) increase with increasing heat load and heat load is a direct function of HDD, any residential heating emissions not subject to, or compliant with the burn bans would have been at the highest January loads and emissions level since before 1951, with a heating load (HDD) 28% higher than the 62 -year mean for January.
In addition to the effect of temperature on heating load, colder temperatures also influence vehicle emissions. Th e motor vehicle emission simulator (MOVES) temperature sensitivity graphs shown in Figure 4 (Choi 2010) indicate that PM 2.5 emissions as well as PM 2.5 precursor emissions of VOC and NOx all increase as temperatures drop from the the 62-year average January temperature (24.0 o F) to the 2013 mean January temperature (14.4 o F), an approximately 10 -degree departure from normal mean monthly temperatures for January. The emission increases are not large, but all species except the PM 2.5 from diesel vehicles are shown to trend upward as the temperature drops from 24 o F to 14 o F. To be clear, source activities related to population and traffic are flat or declining, but the purely meteorological influence of colder temperatures causes higher emissions at the same time that the persistent inversion traps pollutants through the afternoon, causing many consecutive days of accumulation.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A-9 Figure 3. Logan, Utah, heating degree days in 2013 v er sus 1951 –2013 period of record (WRCC 2014).Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 10 Gasoline Vehicles Diesel Vehicles

Figure 4. Temperature sensitivity for gasoline and diesel vehicles in the MOVES2010b model (Choi 2010).Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 11 

## 5 Why Franklin County, Idaho, PM 2.5 

## W as Higher in 2013

The previous sections have shown that an extremely persistent high pressure system predominated in January 2013; source activity for major sources declined or remained flat throughout the month; and cold air by itself can contribute to increased emissions. The following analysis demonstrates that the key factor in producing extreme PM 2.5 levels is not so much the strength or depth of the inversion, but rather the number of consecutive days that the afternoon lower stable layer persists without breakup, and that 2013 had the longest such period in the last decade.



### 5. 1 Assumptions

1. Maximum 24-hour PM 2.5 concentration increase rate (μg/m 3 per day) in a strong stagnation episode is more or less constant assuming the constant emissions. 2. Maximum 24-hour PM 2.5 concentration increase rate (μg/m 3 per day) in a strong stagnation episode is positively correlated with emission level. 3. A d eep stable layer (DSL) with a thickness of 500 meters above ground level or more (12Z soundings) indicates a stagnation condition. A deep stable layer is defined as a condition in which 65% of the layer from 0 to 1,500 meters is stable. 4. A low stable layer (LSL) of 50 meters or more above ground level (in the lowest 500 meters, 0Z soundings) between two consecutive DSL days indicates a continuous DSL episode in which the PM 2.5 concentration on one day will accumulate in the next day with a roughly constant rate. 5. The maximum PM 2.5 elevation in a severe stagnation episode can be conceptually estimated by Equation 1 :

C = R (mixing height, emission rate) x N Equation 1. Conceptual m odel

.

where: R (a function of mixing height and emission rate) is the concentration increase rate that can be estimated using the data from most recent episode.

N is the number of days in the first stage (increasing PM 2.5 stage) of the episode, which should be continuous without breakup, i.e., a LSL exists at 0Z, the afternoon sounding between any two consecutive DSL days.

6. There could be brief breakups or relief during an episode, therefore, the above estimation is for the maximum level and the actual level is usually lower. 7. There could be exceptional situations in which the PM 2.5 level may increase extremely fast, such as 50 μg/m 3 per day or more. This kind of extreme situation is not considered in this study.



### 5. 2 Conceptual Model

While the PM 2.5 formation and concentrations depend on complicated emission and weather patterns, experience has shown that pollutant levels could be estimated by relatively simple box models. During severe stagnation episodes, both vertical and horizontal dispersion are limited. InCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 12 the deep valleys, inversions establish early before dusk, and mixing height in afternoon may never reach the level that allows pollutants to disperse; as a result, pollutants will persistently increase for days. The conventional dispersion models and photochemistry models often fail to properly simulate this situation due to the lack of accurate meteorological information near the surface. An example of community multiscale air quality (CMAQ) modeling results are shown in Figure 5 (UDAQ 2014). It can be seen that the PM 2.5 levels constantly increase at a linear rate during the episodes; the highest concentration is roughly proportional to the number of the days of the episode, as suggested in Equation 1. While the R in Equation 1 depends on the mixing height and emission rate, it is observed that R remains nearly constant over several episodes. The number of days without afternoon LSL breakup (N) is also relatively easy to predict from largescale weather forecasting.

Figure 5. Examples of PM 2.5 episodes in which PM 2.5 concentrations accumulated at a nearly constant rate.
Based on this consideration, R can be determined using the data from the most recent severe stagnation episodes and the number of days of an episode. N is the only parameter needed to estimate the potential maximum PM 2.5 level. The longer the episode duration, the higher the potential maximum PM 2.5 level could be.
While the duration of episodes can be forecasted using the DSL method (Wolyn and McKee 1 968), and the DSL method was found to be applicable to the Boise, Idaho, airshed, the atmospheric stability with respect to trapping inversions in the Cache Valley is better defined using an LSL scheme because it is found that DSL thickness could vary in a great range, which results in uncertainties in determining the effect on the polluted layer. In other words, the layer above 500 meters may be deeply stable, but if the lower stable layer below 500 meters still breaks up in the afternoon, the accumulation is interrupted and PM 2.5 levels drop or stopCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 13 accumulating. Figure 6 and Figure 7 clearly show that the PM 2.5 events are defined by the existence of LSL.

Figure 6. Salt Lake City, Utah, PM 2.5 events defined by lower stable layer. PM 2.5 and lower stable layer data are both from Salt Lake City.

Figure 7. Franklin, Idaho, 2013 episode defined by lower stable layer. PM 2.5 data are from Franklin County, Idaho, and lower stable layer data are from Salt Lake City, Utah, upper air soundings. 0 1

0 10 20 30 40 50 60 70 80LSL (Yes/No)24hr PM2.5(g/m3)

Date



## PM 2.5 

## Levels and LSL Salt Lake City

Daily Mean PM2.5 Concentration LSL

0 1

0 20 40 60 80 100 120PM2.524 Concentration *(μg/m3) 

## 2013 Franklin PM 2.5 

## Episode and LSL

24hrPM2.5

LSLCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 14 Data Analysis

T wo major PM 2.5 events occurred in the past decade, early 2005 and early 2013, as shown in Figure 8 and Figure 9, respectively. The events in 2005 were shorter with the longest one about 7

– 8 days. The valid LSL data are not available for 2005; however, it could be determined from the incomplete data that the 2005 episodes were much shorter and milder.
From Figure 8, the R value estimated from the first event is about 18.7 μg/m 3 per day, and the R value estimated from the linear portion in the main episode in Figure 9, is about 13.7 μg/m 3 per day. The episode during in 2013 is much longer than that in 2005, therefore the highest PM 2.5 concentration in 2013 was much higher than in 2005, while the R value is lower in 2013 probably reflecting lower emissions.

Figure 8

. PM 2 .5 events in Franklin, Idaho, early 2005. 0 10 20 30 40 50 60 70 80 90PM2.524-hr Concentration (μg/m3)

Date



## Franklin 24 hr PM 2.5 

## , 2005Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 15 Figure 9. PM 2 .5 events in Franklin County, Idaho, early 2013.

The skew-T diagrams for 2013 and 2005 show that the stable system is much stronger in 2013, while the mixing heights in afternoon were similar (Figure 10 and Figure 11). The lower R value in 2013 can be partially explained by the reduced emission rate since 2005. The emission rate in 2013 is about 80% of emissions in 2005 (UDAQ 2014), and the R value is about 70% in 2013 compared to 2005. This supports the theory that R varies with emissions and suggests emissions are lower in 2013, in agreement with the emission inventory (UDAQ 2014). 0 20 40 60 80 100 1201/1/20131/3/20131/5/20131/7/20131/9/20131/11/20131/13/20131/15/20131/17/20131/19/20131/21/20131/23/20131/25/20131/27/20131/29/20131/31/20132/2/20132/4/20132/6/20132/8/20132/10/20132/12/20132/14/20132/16/20132/18/20132/20/20132/22/2013PM2.524-hr concentration (μg/m3)

Date



## 24hr PM 2.5 

## Franklin ID, 2013Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 16 Figure 10. A skew-T diagram in a typical day in 2013 episode.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 17 Figure 11. A skew-T diagram in a typical day in 2005 episode.
Figure 12 shows the consecutive LSL days of the longest episode in each year in the past decade. The January 2013 episode had the longest LSL event. While it is not the only factor affecting the severity of the pollution episode, it is clear that the meteorological conditions in the 2013 episode made it one of the worst in recent years and are responsible for the sharp upturn in days exceeding the 24-hour PM 2.5 NAAQS.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 18 Figure 12

. Longest consecutive lower stable layer days in each y ear ; the 2013 event had the longest duration in the past decade.
In conclusion, PM 2.5 accumulates during severe stagnation events. The accumulation rate depends on the average mixing height and emission rate. The average mixing height in a severe stagnation episode is assumed to be similar; therefore, the accumulation rate is largely dependent on the emission rate only. The stagnation episode in 2013 was the strongest and longest in the past decade, therefore, while the accumulation rate, R, is smaller than 10 years ago due to the reduced emission rate, the maximum PM 2.5 concentration reached 102 μg/m 3 due to the longer duration of the episode. 0 2 4 6 8 10 12

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013Number of days of continuous LSL 

## Number of days of Longest Lower Stable Layer (LSL)

- episode each year



# in Salt Lake CityCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 19 

## 6 References

DEQ (Idaho Department of Environmental Quality). 2012. Cache Valley PM 2.5 Nonattainment Area State Implementation Plan. Pocatello, ID: DEQ.

Choi , D., M. Beardsley, D. Brzezinski, J. Koupal, and J. Warila, 2010

. “ MOVES Sensitivity Analysis: The Impacts of Temperature and Humidity on Emissions. ” Presented at the 19th Annual International Emission Inventory Conference : Emissions Inventories - Informing Emerging Issues. , San Antonio, TX.

Funk, C. , A. Hoell, and D. Stone. 2014 . "Examining the Contribution of the Observed Local Warming Trend to the California Droughts of 2012/12 and 2013/14." Bulletin of the American Meteorological Society. 95.9: S11

– 15.

Swain, D. L., M. Tsiang, M. Haugen, D. Singh, and A. Charland. 2014. "The Extraordinary California Drought of 2013/2014: Character, Context, and the Role of Climate Change." Bulletin of the American Meteorological Society

. 95.9 : S3

– S7.
Wang, H. , and S

. Schubert. 2014 . "Causes of the Extreme Dry Conditions over California During Early 2013." Bulletin of the American Meteorological Society

. 95.9: S7

– S11.
UDAQ (Utah Division of Air Quality). 2014. PM 2.5 State Implementation Plan, Weight of Evidence in the Model Attainment Test . Salt Lake City, UT: UDAQ.

UDOT (Utah Department of Transportation). 2014. “Traffic on Utah Highways (AADT)

. ” Accessed October 2014. http://www.udot.utah.gov/main/f?p=100:pg:0::::V,T:,529.

US Census Bureau. 2014. “ State & County Quick Facts. ” Accessed September 2014. http://quickfacts.census.gov/qfd/states/16/16041.html.
Wolyn P.G. and T.B. McKee. 1968. “ Deep Stable Layers in the Intermountain Western United States. ” Monthly Weather Review. 117 : 461

– 472.

WRCC (Western Regional Climate Center). 2014. “ Cooperative Climatological Data Summaries. ” Accessed October 2014. http://www.wrcc.dri.edu/summary/Climsmut.html.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 20 

### Attachment A

January 2: A Rex block has developed over the Pacific Coast. This forces the air to travel into Canada before entering Idaho. This promotes dry, cold transport into Idaho.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 21 January 3: The low pressure system responsible for the Rex block has devolved into an open wave but is still steering the winds in this same pattern while the high pressure system associated with the Rex block as shifted to the east putting southwestern Idaho directly along the ridge axis. This promotes stagnant, stable weather.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 22 January 5: Again, this ridge is evident with the ridge axis located directly along th e Idaho/Oregon border.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 23Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 24Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 25 January 15

– 21: Offshore ridge of high pressure is strongly amplified and steering cold, dry, continental Canadian wind into Idaho. This pattern remains for a week. This pattern promotes a consistent northwest wind pattern that is typically quite dry.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 26Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

A- 27 January 22

– 23: This ridge axis shifts to center directly over southwestern Idaho once more. Again, this promotes stagnant winds. The 20,000 -foot wind speeds are at 10 miles per hour (mph ) near the ridge axis on January 22

, while accelerating to 35 mph on January 23. This image also allows the identification of a strong upper level low pressure system in the Gulf of Alaska with an elongated trough that is likely the cause of clearing for this particular stagnation event.Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

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B-1 

## Appendix B. Updated Road Sanding AgreementsCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

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B-3Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

B-4Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

B-5Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

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C-1 

## Appendix C

. Woodstove Change OutsCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

C-2Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

C-3Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

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D-1 

## Appendix D

. Public InvolvementCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

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D-3 

### Proof of PublicationCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D-4Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D-5Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D-6Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D-7Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D-8Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D-9 

### Sign-In RosterCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

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D- 11 

### Official Public Hearing TranscriptCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D- 12Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D- 13Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D- 14Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D- 15Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D- 16Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D- 17Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D- 18Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D- 19Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D- 20Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D- 21Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D- 22Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D- 23Cache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

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D- 25 

### Response to Public Comments

The Idaho Department of Environmental Quality (DEQ) received one written comment and one oral comment at the public hearing held on December 10, 2014. None of the comments received raised substantive issues requiring modification to the proposed Cache Valley Idaho PM 2.5 Nonattainment Area State Implementation Plan Amendment. The following details both the comments and DEQ’s response to those comments.
Comments from the Public Hearing

Comment 1

— Dirk Bowles: I just wanted to comment that the education that I’ve received over the last five years, I think, that we’ve been meeting with the DEQ and with Melissa has been very important to me personally just to understand what these different

– what all the acronym s mean, for one thing, but also just the importance of the SIP agreement and how dedicated they have been in working through that with us to make it most cost effective for us to try to come into compliance. As an elected official, I just really appreciate the many trips down here and the patience they’ve had with us in answering our questions and helping us, hopefully get this passed and get through the process so that we will really get the air quality that we desire and what is necessary for use to have the quality of life we want. But that’s all.
Response to Comment 1

— No response is necessary.
Comments from E-mail

Comment 2

— Trent Gudmundsen: The EPA currently allows masonry heaters (defined as sitebuilt and weighing more than 800kg). After researching what that means, I found that masonry heaters are much cleaner-burning, and use far less fuel wood, than most EPA-certified woodstoves; the conclusion being that the best alternative is not even mentioned as a viable option in the current amendment.
Pellet stoves are specifically mentioned, and yet masonry heaters are not. Even if masonry heaters are not mentioned, I strongly encourage the mention of "EPA-exempted" options. And on a more personal and local level, I strongly encourage those who are unfamiliar with this technology (as I was until recently) to research the efficiency and other benefits of masonry heaters. There is much information that can easily be found online regarding the superior efficiency of masonry heaters.
One fear I have is that such things may inadvertently be outlawed (or at least frowned-upon) due to lack of specific exemption or allowance in amendments such as that being discussed for the Cache Valley, ID area. Another fear I have is that specific local businesses who sell manufactured woodstoves (including pellet stoves) will unfairly benefit while those wishing to site-build, or have constructed on site, a masonry heater will be unfairly disadvantaged by not being mentioned as a viable alternative.
If those who write the laws in Idaho will be open to lesser-known clean-burning options such as the masonry heater, I believe we could quickly become known as a forward thinking and environmentally minded area of the country, and could be instrumental in helping to orchestrate a paradigm shift in thinking. It is my hope, therefore, that masonry heaters will not only beCache Valley Idaho PM 2.5 Nonattainment Area SIP Amendment

D- 26 specifically exempted from being regulated in Idaho ("exempt" being the EPA's wording), but also be specifically allowed, and the education about such be encouraged.
Response to Comment 2

— The comment is outside the scope of the amendment; no changes or modifications to the local residential wood combustion ordinances were part of this amendment, and therefore no comment is necessary.