# Request for EPA C oncurrence as

E xceptional E vents for the
Feb ruary 15

– 16, 2011

, H igh W ind PM 10 

# D ust E vent

A ffecting H igh PM 10 

# C oncentrations at the Boise Fire Station, Ada County and Nampa Fire Station, Canyon

County

, Idaho

State of Idaho

Department of Environmental Quality

September 2013Printed on recycled paper, DEQ, August 2013, PID MPOB, CA code 81630. Costs associated with this publication are available from the State of Idaho Department of Environmental Quality in accordance with Section 60

- 202, Idaho Code.Request for Concurrence PM 10 Exceptional Events

iii 

## Table of Contents

Acronyms, Abbreviations, and Symbols

................................ ................................ ...................... vii
Executive Summary

................................ ................................ ................................ ....................... ix

1 Conceptual Model

................................ ................................ ................................ .................... 1

1.1 Overview

................................ ................................ ................................ .......................... 1

1.2 Source Area and Affected Region

................................ ................................ .................... 1

1.3 Emissions Process

................................ ................................ ................................ ............ 3

1.4 Contributing Weather Phenomena Synopsis

................................ ................................ .... 5

1.5 Path and Timeline from Source Area to Monitors

................................ ........................... 5

1.6 Concentration Patterns

................................ ................................ ................................ ...... 6

2 Not Reasonably Controllable or Preventable (nRCP)

................................ ............................. 9

2.1 Source Areas Contributing to the Event

................................ ................................ ........... 9

2.2 Source Area Wind Speeds

................................ ................................ .............................. 10

2.3 Basic Controls Analysis

................................ ................................ ................................ . 10

3 In Excess of Historical Fluctuations (HF)

................................ ................................ ............. 11

3.1 Time Series for the Previous Ten Years

................................ ................................ ......... 11

3.2 Percentile of Concentrations

................................ ................................ ........................... 15

4 Clear Causal Relationship (CCR)

................................ ................................ .......................... 16

4.1 Occurrence and Geographic Extent of the Event

................................ ........................... 16

4.2 Description of Weather Conditions that Created the Event

................................ ........... 22

4.3 Transport of Emissions Related to the Event in the Direction of the Monitor(s)
Where Measurements Were Recorded

................................ ................................ ........ 31

4.4 Spatial Relationship Between the Event, Sources, Transport of Emissions, and
Recorded Concentrations.

................................ ................................ ........................... 34

4.5 Temporal Relationship Between the High Wind and Elevated PM Concentrations at the Monitor(s) in Question

................................ ................................ .......................... 34

4.6 Similarity of Chemical Composition of Measured Pollution with that Expected from Sources Identified as Upwind

................................ ................................ ..................... 34

4.7 Comparison of Event

- Affected Days to Specific Nonevent Days

— Comparison of Area Concentrations and Wind Speeds in the Days Preceding and Following the

Event

................................ ................................ ................................ ........................... 40

4.8 Alternative Hypotheses

................................ ................................ ................................ .. 40

5 Affects Air Quality (AAQ)

................................ ................................ ................................ .... 42

6 Natural Event or Human Activity Unlikely to Recur at the Same Location (NE/HAURL)

. 42

7 No Exceedance But For this Event (NEBF)

................................ ................................ .......... 43

8 Mitigation

................................ ................................ ................................ .............................. 44

9 Procedural Requirements

................................ ................................ ................................ ....... 45

10 References

................................ ................................ ................................ .............................. 46Request for Concurrence PM 10 Exceptional Events

iv 

### Appendix A. EPA Completion Checklist

................................ ................................ ..................... 50
Appendix B. Supporting Meteorological Data

................................ ................................ ............. 52
Appendix C. Hells Canyon IMPROVE Site PM 2.5 

### Speciation

................................ ..................... 63 Appendix D. St. Luke’s Meridian NCORE Site Speciation Data for February 14, 2011

............ 65
Appendix E. DEQ Air Quality Alerts and Public Education

................................ ........................ 67 Appendix F. News Articles

................................ ................................ ................................ ........... 71



## List of Tables

Table A. Monitored values Included in this request for concurrence.

................................ ........... ix
Table B. Summary of DEQ demonstration in this report meeting Exceptional Event Rule
elements.

................................ ................................ ................................ ........................... x Table 1. Statistics of 24

- hour PM 10 

### concen trations recorded in Boise and Nampa, 2002

– 2011.

. 11 Table 2. Percentile statistics with respect to annual and seasonal datasets, w ith and without high wind days, 2002

– 2011.

................................ ................................ ........................... 16 Table 3. Hourly PM 10 

### concentrations greater than 100 μg/m 3 

### at the Nampa fire station for winter 2010 and 2011 only. Values related to this dust event are shown in bold (red circles in Figure 32).

................................ ................................ ................................ ....... 38 Table 4. Compa rison of February 14 St. Luke’s monitoring site PM 2.5 

### composition with the annual average and winter season historical compositions, 2009

– 2011.

....................... 39 Table 5. Average, 95th and 99th percentile of PM 10 

### concentrations ( μ g/m 3 

### ) in Boise and Nampa, 2002

– 2011, in comparison to recorded values during this event. S tatistics are shown for all data (top) and winter season (bottom).

................................ ............... 44 Table 6. DEQ compliance with procedural requirements of the exceptional events rule.

............ 45
Table A

- 1. EPA completion checklist.

................................ ................................ ......................... 50
Table B

- 1. Identification of MESOWEST stations used in this report (Horel et al. 2002).

......... 52
Table B

- 2. Source region weather station data from Mesowest (Horel et al. 2002).

.................... 53
Table B

- 3.Intermediate (Oregon) and affected area weather stations from MESOWEST (Horel et al. 2002).

................................ ................................ ................................ .......... 55
Table B

- 4. Weather observations at Lovelock, Boise, and Winnemucca from Mesowest (Horel et al. 2002).

................................ ................................ ................................ .......... 57
Table B

- 5. Daily precipitation in source region, January 1

– February 15, 2011 (Horel et al. 2002).

................................ ................................ ................................ .............................. 62
Table D

- 1. St. Luke’s NCORE site speciation for February 14, 2011

— XRF elements.

............. 65



## List of Figures

Figure 1. Loca tion of Black Rock Playa and Carson Sink Playa source areas, affected PM 10 

### monitors at Boise and Nampa, and MESOWEST weather stations referenced in this
report.

................................ ................................ ................................ ................................ 2 Figure 2. Schematic illustration of relationship between high dust potential and a near

- surface capillary fringe zone on a wet playa versus a lower dust potential for a dry playa (Reynolds et al. 2007).

................................ ................................ ................................ ...... 3Request for Concurrence PM 10 Exceptional Events

v 

### Figure 3. Playa dust storm example near Carson Sink Playa, March 28, 2012.

............................. 4 Figure 4. (a) Boise and Nampa PM 10 

### concentrations, (b) southwest Idaho hourly PM 2.5 

### concentrations, and (c) wind conditions at the Boise airport from MESOWEST (Horel et al. 2002).

................................ ................................ ................................ ............ 7 Figure 5. (a) Surface wind speed, (b) wind gusts, and (c) wind directions at source area sites (BLUN2, BUF N2, TR730, and KLOL) and intermediate distances (GSFO3 and JVCI1) between source area and affected area. Figure 1 provides locations, and Appendix B provides station information and tabular data obtained from MESOWEST (Horel et al. 2002).

................................ ................................ ..................... 8 Figure 6. Twenty

- four hour PM 2.5 

### concentration pattern in southwest Idaho on February 12, 2011, (first bar) through February 17, 2011 (last bar) . PM 2.5 

### is a surrogate for PM 10



### . .... 9 Figure 7. Historical PM 10 

### fluctuations at Boise fire station no. 5, 2002

– 2011. Values over
120 μ g/m 3 

### are identified by date along with the maximum 1

- hour wind speed/gust speed for that day.

................................ ................................ ................................ ........... 12 Figure 8. Historical PM 10 

### fluctuations at the Nampa fire station, 2002

– 2011. Values over
120 μ g/m 3 

### are identified by date along with the maximum 1

- hour wind speed/gust speed for that day.

................................ ................................ ................................ ........... 13 Figure 9. PM 10 

### concentration (blue dots) and paired maximum daily 1

- hour wind speed (=SKNT, red line) at the Boise fire station, sorted by decreasing wind s peed with the highest wind speeds to the left.

................................ ................................ ....................... 13 Figure 10. Daily mean PM 10 

### concentration (blue dots) and paired 1

- hour maximum w ind speed (=SKNT, red line) at Nampa fire station sorted by decreasing wind speed with the highest wind speeds to the left.

................................ ................................ ................. 14 Figure 11. PM 10 

### concentration distribution, 2002

– 2011, at the Boise fire station.

...................... 14 Figure 12. PM 10 

### concentration distribution, 2002

– 2011, at the Nampa fire station.

.................... 15 Figure 13. MODIS true color image from the Terra satellite, captured at ~1030 PST on February 14, 2011.

................................ ................................ ................................ .......... 18 Figure 14. MODIS Aqua image captured at ~1330 PST on February 14, 2011.

.......................... 19 Figure 15. MODIS true color image from the Terra satellite, captured at ~1030 PST on February 15, 2011.

................................ ................................ ................................ .......... 20 Figure 16. MODIS Aqua image captured at ~1330 PST on February 15, 2011.

.......................... 21 Figure 17. MODIS Aqua false color images (clou ds and snow are blue

- tinted; dust is white) showing turbulent dust cloud generation on Black Rock Playa (left) and Carson Sink Playa (right) as well as dust plumes leaving the playas toward the northeast ~1330 PST February 15, 2011.

................................ ................................ ................................ .. 22 Figure 18. Twenty

- four hour precipitation totals in the BRP and CSP source region in the
45 days prior to the event.

................................ ................................ .............................. 23 Figure 19. 1800Z (1100 MST) surface analysis February 15, 2011 (National Weather Service Hydrometeorological Prediction Center: http://www.hpc.ncep.noaa.gov/htm l/sfc_archive.shtml).

................................ ............... 24 Figure 20. 2100Z (0200 MST) surface analysis February 15, 2011 (National Weather Service Hydrometeorological Prediction Center: http://www.hpc.ncep.noaa.gov/html/sfc_archive.shtml).

................................ ............... 24 Figure 21. NCEP/NARR model reanaly sis of midlevel winds (meters per second), February
14

– 15, 2011 (NOAA/ESRL Physical Science Division, Boulder Colorado: http://www.esrl.noaa.gov/psd/).

................................ ................................ ..................... 25Request for Concurrence PM 10 Exceptional Events

vi 

### Figure 22. Sounding information for Reno, Nevada, at 18Z (1100 PST) February 15, 2011 (National Weather Service Upper

- Air Observations Program

- Global Climate Observing System. University of Wyoming Sounding: http://weather.uwyo.ed u/upperair/sounding.html).

................................ ........................ 26 Figure 23. Friction velocity for 18Z (1200 MST) February 15, 2012, NARR NAM

- ANL (National Climatic D ata Center National Operational Model Archive and Distribution System, NWS

- NCEP NAM, 12 km: http://nomads.ncdc.noaa.gov/data.php?name=access#hires_weather_datasets).

........... 27 Figure 24. Sounding information for Boise, Idaho, at 12Z (0500 MST) February 16, 2011 (National Weather Service Upper

- Air Observations Program

- Global Climate Observing System. University of Wyoming Sounding: http://w eather.uwyo.edu/upperair/sounding.html).

................................ ........................ 28 Figure 25. 1500Z (0800 MST) surface analysis February 16, 2011 (National Weather Service Hydrometeorological Prediction Center: http://www.hpc.ncep.noaa.gov/html/sfc_archive.shtml).

................................ ............... 29 Figure 26. 1800Z (1100 MST ) surface analysis February 16, 2011 (National Weather Service Hydrometeorological Prediction Center: http://www.hpc.ncep.noaa.gov/html/sfc_archive.shtml).

................................ ............... 29 Figure 27. Surface winds 1500 MST on February 15, 2011, from MESOWEST (Horel et al. 2002).

................................ ................................ ................................ .............................. 30 Figure 28. HYSPLIT back

- trajectories from the 0500

– 1000 MST PM 10 

### peak at Boise

- Nampa area on February 15, 2011 (NOAA Ready HYSPLIT model: http://ready.arl.noaa.gov/HYSPLIT_traj.php).

................................ ............................... 32 Figure 29. HYSPLIT back

- trajectories from the 1600

– 2400 MST PM 10 

### peak at Boise

- Nampa area on February 15, 2011 (NOAA Ready HYSPLIT model: http://ready.arl.noaa.gov/HYSPLIT_traj.php).

................................ ............................... 33 Figure 30. HYSPLIT back

- trajectories for the Boise

- Nampa area PM10/PM2.5 impact period
2100

– 2300 MST, February 14, 2011 (NOAA Ready HYSPLIT model: http://ready.arl.noaa.gov/HYSPLIT_traj.php).

................................ ............................... 35 Figure 31. February 14, 2011, PM 2.5 

### composition (NCORE 2013) compared to Black Rock Playa surface soil composition (Gillett 1997).

................................ ............................... 36 Figure 32. PM 2.5 

### /PM 10 

### ratio at the Nampa fire station s orted from low to high (red line, left axis) versus paired 1

- hour PM 10 

### concentration (blue dots).

................................ ........... 38 Figure 33. Event

- affected da ys along with nonevent days before and after the February 14

– 16, 2011, event.

................................ ................................ ................................ .................... 40 Figure C

- 1. Hells Canyon speciation for February 2011, showing high coarse mass (top) and elevated soil component on February 14, 2011.

................................ ............................. 63 Figure C

- 2. Hells Canyon speciation for February 2011 showing higher Si, Fe, Al, and Ca on February 14, 2011.

................................ ................................ ................................ .......... 64Request for Concurrence PM 10 Exceptional Events

vii 

# Acronyms, Abbreviations, and Symbols

μg microgram

μm micrometer

AAQ affects air quality

BRP Black Rock Playa

Ca calcium

CCR clear causal relationship

CFR Code of Federal Regulations

CSP Carson Sink Playa

DEQ Idaho Department of

Environmental Quality

EER Exceptional E vents R ule

EPA United States Environmental

Protection Agency

FR Federal Register

FS fire station (Boise and

Nampa)

HAUR human activity unlikely to

recur

HAURL human activity unlikely to

recur at a particular location

HF historical fluctuations

HYSPLIT Hybrid Single Particle

Lagrangian Integrated Trajectory

IMPROVE Interagency Monitori ng of

Protected Visual
Environments

km kilometer

m meter

mb millibar

mph miles per hour MODIS Moderate Resolution Imaging Spectroradiometer

MST mountain standard time

Na sodium

NAAQS National Ambient Air

Quality Standard

NAM

- ANL North American Mesoscale

Model

- Analysis

NASA National Aeronautics and

Space Administration

NE natural event

NEBF no exceedance but for

NCEP National Center for

Environmental Prediction

NCORE National Core air monitoring

network

NOAA National Oceanic and

Atmospheric Administration

nRCP not reasonably controllable or

preventable

NWS National Weather Service

PM 10 

### particulate matter 10

micro meters and smaller

PM 2.5 

### particulate matter 10

micro meters and smaller

PST Pacific standard time

s second

SIP state implementation plan

TFV thresh old friction velocitiesRequest for Concurrence PM 10 Exceptional Events

viii 

### This page intentionally left blank for correct double

- sided printing.Request for Concurrence PM 10 Exceptional Events

ix 

# Executive Summary

Northern Ada County is designated as a m aintenance a rea for the National Ambient Air Quality Standard (NAAQS) for particulate matter 10 micro meters and smaller (PM 10 

### )

, and the Idaho Department of Environmental Quality ( DEQ ) has just completed the second 10

- year maintenance plan . While PM 10 

### levels have declined to well below the 150 micrograms per cubic meter (  g/m 3 

### ) standard since the last violation in 1991, a white haze settled in the area on February 14

– 16, 2011, causing the PM 10 

### standard to be exceeded on February 15 and 16, 2011

, at the Boise f

ire s tation ( Boise FS) and on February 15 at the Nampa f ire s tation (Nampa FS).

To address exceptional events that are not reasonably controllable or preventable, the United
States Environmental Protection Agency ( EPA ) promulgated the Exceptional Events Rule (EER)
in 40 CFR 50 and 51 (72 FR 13560) on March 22, 2007. The EER allows for states to flag air quality data as exceptional and exclude those data from use in determin ing compliance with the NAAQS, if EPA concurs with the state’s demonstration that it satisfies th e rule requirements

.
In accordance with the EER procedures, DEQ flagged two values at the Boise FS monitor and

one at the Nampa FS monitor as indicated in Table A. DEQ demonstrates in this report, and requests EPA concurrence, that these three concentration values occurred as a result of natural conditions in another state, not reasonably controllable or preventable by the State of Idaho, fully meeting the criteria of the EER.

Table A. Monitored v alues Included in this r equest for c oncurrence

.

Monitor Site: Boise Fire Station No. 5, Ada County, Idaho Nampa Fire Station, Canyon County

, Idaho
Monitor ID (AQS#/POC): 16

- 001

- 0009 (POC 3) 16

- 027

- 0002 (POC 2)

Date PM 10 Concentration Recorded,  g/m 3

2/15/2011 183 174

2/16/2011 156 a

Notes : Particulate matter 10 micro meters or smaller (PM 10 ); micrograms per cubic meter (  g/m 3 )
a. E levated PM 10 concentrations of 55 and 68  g/m 3 at the Boise and Nampa fire stations, respectively on February

14

, 2011, and 108  g/m 3 at the Nampa fire station on February 16

, 2011

, were also influenced by the same multiday high wind event, however

, concurrence is not requested for any values below the standard (150  g/m 3 ).



### The EER requi res that demonstrations to justify data exclusion as exceptional events shall provide evidence that the event ( a) affects air quality (AAQ); ( b) is not reasonably controllable or preventable (nRCP), ( c) is a natural event or is an event caused by human activity that is unlikely to recur at a particular location (NE/ HAURL); ( d) that there is a clear causal relationship (CCR) between the identified source and measurement under consideration; ( e) that
the event is associated with measured concentrations in excess of normal historical fluctuations (HF), including background; and ( f) that there would have been no exceedance or violation of the
standard but for the event (NEBF). In additio n, the s tate must document that prompt public notification procedures and measures to reduce public exposure were followed and that the public comment process was followed in reviewing th e demonstration. DEQ’s demonstration satisfying these elements is summarized in Table B , which identifies the repo rt sectionRequest for Concurrence PM 10 Exceptional Events

x 

### containing each element of the demonstration. In addition, EPA’s detailed checklist for specific
items recommended in the h igh w ind s trategy g uidance (EPA 2013) is included in Appendix A

.

Table B

. Summary of DEQ d emonstration in this r eport meeting E xceptional E vent R ule e lements

.
E xceptional Event Rule (EER) Element Sect ion Summary

Conceptual m odel ( United States
Environmental Protection Agency guidance, not an EER

e lement) 1 The conceptual model describes the source

, natural dry lake beds or playas in
northwest Nevada

, high wind conditions

, emissions mechanisms leading to
the event , and transport conditions and concentration patterns. Impact ar ea wind conditions contributing to high particulate matter 10 micro meters or smaller ( PM 10 ) levels remaining in place over portions of 2 days are also presented.

Not r easonably

c ontrollable or

p reventable (nRCP) 2 Pleistocene e poch dry lake bed playa surfaces, including Black Rock Playa (BRP) and Carson Sink Playa (CSP) are identified as the source areas. These
are natural areas in another state that were exposed to winds over the wind speed threshold for natural areas and dust generation from them is not reasonably controllable or preventable (nRCP)

. In addition, there are no anthropogenic sources capable of contributing dust levels as high as those experienced during this event.

Exceeds h istorical
f luctuations (HF) 3 The PM 10 concentrations on Feb ruary 15 and 16, 2011

, are the highest 24

- hour concentrations observed in over 10 years at the Boise f ire s tation , and
the Feb ruary 15 concentration is the second highest observed at the Nampa
f ire s tation in the previous 10 years. A comparison to annual and seasonal data sets for the last 10 years is provided showing that normal historical fluctuations (HF ) are well below these levels.

Clear c ausal

r elationship (CCR) 4 Evidence provided show s that the playas of northwest Nevada, notably BRP and CSP, are the source of dust impacting the Boise

- Nampa area on Feb ruary 15 and 16, 2011. Evidence includes wind data at the source area and at
monitors ; satellite images of dust blowing toward Boise

- Namp a ; back

trajectories linking BRP and CSP with the monitors in question ; and chemical composition fingerprinting of the BRP soils that matches National Core (NCORE) a ir m onitoring network air filters collected on Feb ruary 14, 2011

, the first day of the even t. A lternative source hypotheses are discussed and shown

to be incapable of creating levels this high.

Affects a ir q uality (AAQ) 5 The affects air quality (AAQ) element is met by demonstrating PM 10 in excess
of historical fluctuations (HF) and a clear causal relationship (CCR) between
source and monitored values.

Natural e vent or h uman

a ctivity u nlikely to r ecur (NE/HAUR) 6 The natural event/human activity unlikely to recur (NE/HAUR) criterion is met by demonstrating that the event is a natural event t hat is not reasonably controllable or preventable (nRCP) and that there is a clear causal relationship (CCR) with the identified natural source area.

No e xceedance b ut f

or

e vent (NEBF) 7 Nonevent PM 10 levels are typically well below the National Ambient Air Quality Standards . A quantitative no exceedance but for (NEBF) analysis for the last
10 years shows that PM 10 levels are typically not more than 23 to 66 micrograms per cubic meter (  g/m 3 ) for Boise and 24 to 78  g/m 3 for Nampa (annual average to 99 th percentile )

. T he three PM 10 values under
consideration all exceed the 99th percentile background level by more than
90  g/m 3

. No other unusually significant sources were present during the

event period

. Thus, t here would be no exceedance but for (NEBF) the high wind event involving the BRP and CSP source areas.

Mitigation 8 DEQ provided prompt public advisor ies of the elevated levels and advice to reduce public health exposure on Feb ruary 15 and 16, 2011.

EER p rocedures 9 DEQ met EER procedural requirements for flagging, demonstration

, and public comment as summarized in this section.Request for Concurrence PM 10 Exceptional Events

1 

# 1 Conceptual Model

1.1 Overview

On February 14 and 15, 2011

, high afternoon winds swept 4,000 square kilometers ( km 2 

### ) of the
flat playa surface covering dry lake beds in northwest Nevada, including the Black Rock Playa (BRP) , and nearby Carson Sink Playa (CSP) , entraining a fine white dust and transporting it
toward the Boise

- Nampa area of southwest Idaho. It arrived in the evening of Feb ruary 15 sending hourly particulate matter 10 micro meters or smaller ( PM 10 

### ) concentrations over

500 micrograms per cubic meter (  g/m 3 

### ) around midnight. Light winds and a weak surface
inversion allowed the fine white dust cloud to remain over the most of th e valley until it mixed out the next morning, causing monitors to exceed the National Ambient Air Quality Standards ( NAAQS ) for PM 10 

### on February 15 and 16 at the Boise f ire s tation (Boise FS) PM 10 

### monitoring
site and on February 15 at the Nampa f ire s tatio n (Nampa FS) monitoring site.



## 1.2 Source Area and Affected Region

The source areas for this event are the flat alkali playas or dry lakebeds , BRP and CSP, and other smaller playas located within the Black Rock Desert region of northwest Nevada. The playas of
western Nevada are clearly capable of producing dust clouds that may affect the Boise

- Nampa

area. Steenburg h et al. (2012) found in a satellite study of episodic dust events impacting the Wasatch Front area of Utah, that for most of the dust events in the period 2001

– 2010, “ emission sources are located primarily in low

- elevation l ate Pleistocene

- Holocene alluvial environments in
southern and western Utah and southern and western Nevada. ” The BRP and CSP of western Nevada are approximately 350 miles from the Wasatch front, but only 200

– 300 miles from the
Boise

- Nampa area so dust emissions and transport from the BRP and CSP to the Boise

- Nampa

area are also likely to occur

. The BRP is over 2,600 km 2 

### in area, one of the largest flat alkali playas o n earth (Adams and Sada 2010). It is an arid region of lava beds and playa that lies within the footprint of late Pleistocene Lake Lahontan at a mean elevation o f 4,000 f ee t (1,220

m eters ) above sea level. The CSP is approximately 1,300 km 2 

### so the total po tentially erodible surface, including other smaller playas

, is around 4,000 km 2 

### (the approximate size of Rhode Island)

.
The affected region around Boise and Nampa is located roughly 250 mi les (400 km) northeast of the source region, however

, elevated particulate levels during the period of February 14

– 16 reached from Idaho City, Idaho

, to Hells Canyon on the Oregon

- Idaho border and as far north as Garden Valley, Idaho (possibly even McCall

, Idaho)

. Boise has a mean elevation of 2,700 f ee t (82 4 m eters ) above sea level. Figure 1 shows the geographic location of Boise FS and Nampa FS
monitors

, the weather stations referenced in this document

, and the BRP and CSP source areas.
Boise lies within the l ower Snake River b asin and the smaller Boise River valley and is subject to the channeling effect of both of these topographic features. Mean wind flow from either the northwest or southeast through the basin is typical when diurnal up/down valley wind flow
patterns dominat e with light synoptic winds. The Nampa FS lies approximately 18 miles west of
the Boise FS at an elevation of about 2,500 feet (762 m eters ). It is also in the l ower Snake RiverRequest for Concurrence PM 10 Exceptional Events

2 

### b asin, however

, it lies outside the Boise River v alley and experiences less of the stagnation and
terrain

- influenced lighter winds that can trap pollutants in the Boise River v alley , as occurred on the morning of February 16.

Figure 1

. Location of Black Rock Playa and Carson Sink Playa source areas, affected PM 10 monitors at Boise and Nampa, and MESOWEST weather stations referenced in this report.Request for Concurrence PM 10 Exceptional Events

3 

## 1.3 Emissions Process

The BRP surface is composed of fine

- grained clay and silt sediments mostly smaller than
3 micrometers ( μm ) in diameter and dominated by mi nerals containing silica, aluminum oxide, iron, magnesium

, and soluble salts ( or evapor i te minerals ) . Evaporite minerals include calcite (CaCO 3 

### ), halite (NaCl)

, and gypsum (CaSO 4 . 

### 7H 2 

### O), which exhibit shrink

- swell properties when wetted and dried, thereby m aking the surface crust looser, less compacted, and more available for wind erosion and transport (Adams and Sada 2010 ; Tollerud and Fantle 2012 ; Lewis et al.
201 1 ; and Reynolds et al. 2007, 2009 ). Reynolds et al. (2007) reports that evaporation of
rainwat er or shallow ground water evaporating through a capillary fringe zone produces fl uffy
erodible sediments when salt crystals such as calcite, halite and gypsum grow during evaporation. To confirm this process Tollerud and Fantle (2012 ) exposed BRP sediments to wetting and drying cycles by simulat ing rain in laboratory tests. They found that added quantities of the evapor i te minerals disrupted the hard clay surface of the sediments through formation and expansion of calcite and halite cr ystals . Reynolds et al. (2007) provides a schematic ( Figure 2 ) showing that the highest potential for dust emission from playas occurs not on dry playas but on

wet p layas when a very shallow capillary fringe exists near the surface due to a shallow water
table or to a recent precipitation event. A wet playa is one with ephemeral hydrologic features, often even a small residual water body reflecting the presence of a s hallow water table. BRP and
CSP both have such features. Lewis et al. ( 201 1 ) attributed one BRP dust storm they studied to antecedent precipitation 2 weeks prior to passage of a high wind front.

Once loose unconsolidated minerals and sediments are produce d by evaporation of rain or shallow ground water

, the fluffy or puffy surface materials with increased calcium and sodium
concentrations are more vulnerable to wind erosion. Ginoux et al

. (2012) and Argama n et al. (2006) both identify wind erosion thresholds above which dust may become entrained to be
around 15 miles per hour (mph) (10 m eters ) for extremely flat surfaces, based on threshold surface friction velocity of 0.6 meters per second ( m/s ) over deserts. Thus for a playa

, any 10

m eter wind over about 15 mph is likely to begin generating dust

. A t wind speeds double or triple that threshold, significant dust production may be expected.

Figure 2

. Schematic illustration of relationship between high dust potential and a near
- surface capillary fring e zone on a wet playa versus a lower dust potential for a dry playa (Reynolds et al. 2007).Request for Concurrence PM 10 Exceptional Events

4 

### The effect of precipitation on the potential for dust from deserts and playas is complex

, and it is important to distinguish the effect of antecedent precipitation in the weeks prior to a high wind event from antecedent precipitation in the months to years prior to high wind dust storms. The former, involving evapor i te formation as described b y Tollerud and Fantle ( 2012 ) ; Lewis et al. ( 2011 ) ; and Reynolds et al. ( 2007, 2009 ) , relates to precipitation in the weeks prior to the dust

storm on nonvegetated playas. The latter, involving reduced wind erosion due to increased vegetation growth promote d by precipitation months to years antecedent to the high wind conditions is also described in the literature (Urban et al. 2009 ; Holcombe et al. 1997 ; and Pelletier 2005). Both effects are well established

, however

, the surface mineral changes bringing

ca lcium and sodium evaporite minerals to the surface as described by Tollerud and Fantle (2012), Lewis et al. (2011)

, and Reynolds et al. (2007

, 2009) are believed to have contributed to the dust storm of February 14

– 16, 2011

, on the largely unvegetated BRP and CSP. Nevertheless,
back

- trajectories, satellite images

, and chemical composition all point to these playas as the source of the dust arriving in Boise

- Nampa area on February 14

– 16, 2011

, irrespective of
mechanism.

During a windy day unrelated to the Fe bruary 2011 event in question, a n Idaho Department of Environmental Quality ( DEQ ) staff person traveling along I nterstate I

- 80 in Nevada observed and photographed large white dust clouds arising from the playa ( Figure 3 ) in the CSP area near Lovelock, Nevada. Th e photo graph in Figure 3 was taken on March 28, 2012

, at app roximately
1300

– 1400 Pacific s tandard t ime ( PST ) when the hourly winds averaged 22 mph and gusts
reached 32 mph at two nearby meteorological stations. The white dust in this photo graph suggested to DEQ that the white haze in Boise and Nampa on Feb ruary 15

– 16, 2011

, might be related to these dry lake beds

. Th e photo graph is included in this report to help the reader conceptualize these dust events and to provide direct , if anecdotal

, evidence that such events may occur with winds at least as low as 22 mph.

Figure 3

. Playa dust storm example near Carson Sink Playa, March 28, 2012

.Request for Concurrence PM 10 Exceptional Events

5 

## 1.4 C ontributing Weather P henomen a Synopsis

A relatively snow

- free playa surface with unseasonably mild conditions allowing for rainfall in
the last 2

- 3 week s of January 2011 resulted in ideal conditions for develop ing an extremely large (~4,000 km 2 

### ) erodible surface on the BRP, CSP

, and other, smaller playa areas in the region. O n February 14

– 16, 2011, a cold front moved through the northwestern Nevada area ca using very high afternoon winds on each day from the southwest blowing toward the Boise

- Nampa area of Idaho approximately 200

– 300 miles away. The dust cloud arrived first on February 14, 2011, then again on the morning of February 15, 2011, and finally the most dense cloud of white dust arrived on the evening of February 15, 2011, causing hourly PM 10 

### concentrations to reach over

500  g/m 3 

### by 23 00 mountain standard time (MST). As the particulate concentrations began to climb, the local wind speeds at the Boi se airport ranged from calm to 18 mph, well below the United States Environmental Protection Agency (EPA) suggested 25 mph threshold velocity for entraining dust from local sources such as natural desert, roadways, unvegetated lots, and agricultural fields (EPA 2013). The Boise airport winds remained relatively low overnight, allowing the dust cloud to remain in the area until morning

. T he dust was advected out of the valley around 0 9 00 MST on February 16

, 2011. To summarize, the weather phenomenon contributing to this event included ( a) antecedent rain 2 to 5 weeks prior, producing a highly erodible surface, ( b) a cold front with sustained high winds on February 14 and 15

, entraining the
dust from some of t he 4,000 km 2 

### of playa, ( c) transport winds carrying the dust from the playas
to the Boise

- Nampa area; and ( d) light winds and a weak surface inversion

, which allowed the
dust cloud to remain in the area overnight , particularly at the Boise site where the s urrounding foothills tend to somewhat mitigate the valley winds, in comparison to Nampa in the midvalley.



## 1.5 Path and Timeline from Source Area to Monitors

The time line of dust impacts in southwest Idaho are shown in Figure 4

, which combines the (a)
Boise

- Nampa hourly PM 10 

### concentrations

, ( b ) southwest Idaho hourly PM 2.5 

### concentrations , and (c) Boise airport wind speeds and directions

. Figure 5 shows the (a) surface wind speeds, (b)
wind gusts

, and (c) wind directions for selected stations in the source area (BLUN2 , BUFN2,
TR730

, and KLOL) and in Oregon along the transport path from the playas to the Boise

- Nampa

area (GSFO3 and JVCI1). Detailed hourly data obtained from the MESOWEST service (Horel et al. 2002) are provided in Appendix B, along with station information, and their locations are
shown in Figure 1. Three distinct periods of dust impacts occurred at the Boise FS and Nampa
FS monitors, typically preceded 8 to 12 hours earlier by high surface winds in the BRP and CSP source areas. High surface winds exceeding 25 mph occurred in the source regions on February
14 and 15 from a round 1200 to 1600 MST with another period of high winds from 0400 to 0800
MST on February 15 . Wind speeds were well above the site

- specific threshold wind speeds (15

– 22 mph) for the onset of wind erosion. The path of dust transport suggested by these wind observations is confirmed by the Hybrid Single Particle Lagrangian Integrated Trajectory ( HYSPLIT ) back

- trajectories presented in section 4.3

.Request for Concurrence PM 10 Exceptional Events

6 

## 1.6 Concentration Patterns

Temporal Patterns

— The rise in dust concentrations, indicated by the hourly PM 10 

### at Boise and Nampa ( Figure 4 ( a ) ) and the PM 2.5 

### concentrations at five locations in the s outhwest ern Idaho

area ( Figure 4 ( b ) ) indicates that the dust arrived at t he southern edge of the area first (Nampa FS
and St. Luke’s Meridian monitoring sites ) then reached more northerly monitors later, beginning with Idaho City, followed by Garden Valley. Garden Valley PM 2.5 

### levels did not increase until
0 200

– 0 400 MST on February 16, suggesting that the dust plume may have passed over Idaho City to the east of Garden Valley, then reached Garden Valley from the east with the night time valley drainage flows of the South Fork Payette River. The PM 2.5 

### peaks at the McCall moni tor suggest that dust may have reached McCall, however

, the increase is small and cannot be positively attributed to the dust storm. These temporal patterns, with southern sites recording higher particulate levels before northern sites

, suggest that the so urce is located to the south of
the Boise

- Nampa area.

Spatial Patterns

— The spatial concentration pattern that occurred from February 12 to 17 is
shown in Figure 6 rep resenting 24

- hour averaged PM 2.5 

### concentrations throughout the southwest
Idaho area. PM 2.5 

### concentrations are shown because there are more PM 2.5 

### monitors than PM 10 

### monitors so they are preferred for reflecting the spatial pattern of the dust. Th e map in Figure 6
shows that the Boise

- Nampa area received the highest concentrations but that the spatial extent of the dust cloud was very broad, reaching the mountainous site s at Idaho City and Garden Valley. The Interagency Monitoring of Protected Visual Environments ( IMPROVE ) aerosol monitoring site at Hells Canyon on the Oregon

- Idaho border (IMPROVE 2013 ; Hand 2011; and
NRC 1993 ) also appears to have elevated PM 2.5 

### on February 14, with higher than normal geologic components compared to the other days in February 2011

. IMPROVE speciation data for Hells Canyon are provided in Appendix C indicating higher PM 2.5 

### , higher coarse mass (> 2.5  m), and enrich ment in the soil co mponent as well as the geologic elements including silicon, iron, aluminum, magnesium

, and calcium

. This broad spatial pattern cannot be explained by typical local

- scale anthropogenic dust sources such as road dust, construction

, or local
industrial facili ties in Ada County, but it suggest s a much larger regional

- scale dust source originating some distance away and widely spread by variable wind directions.Request for Concurrence PM 10 Exceptional Events

7 Figure 4

. (a) Boise and Nampa PM 10 concentrations, (b) southwest Idaho hourly PM 2.5 concentrations

, and (c) wind conditions at the Boise a irport from MESOWEST (Horel et al. 2002)

.Request for Concurrence PM 10 Exceptional Events

8 Figure 5

. (a) Surface wind speed

, (b) wind gusts
, and (c) wind directions at s ource area sites (BLUN2, BUFN2, TR730, and KLOL) and intermediate distances (GSFO3 and JVCI1) between source area and affected area. Figure 1 provides locations

, and Appendix B provides station information and
tabular data obtained from MESOWEST (Horel et al. 2002)

.Request for Concurrence PM 10 Exceptional Events

9 Figure 6

. Twenty

- four hour PM 2.5 c oncentration pattern in s outhwest Idaho on Feb ruary 12 , 2011, (first bar) through Feb ruary 17 , 2011 (last bar). PM 2.5 is a surrogate for PM 10 .



# 2 Not Reasonably Controllable or Preventable (nRCP)

2.1 S ource A reas Contributing to the E vent

The B RP is approximately 2,600 km 2 

### in surface area and extends approximately 100 km in length, trending northeasterly such that winds approaching it from 220 degrees and eroding dust along its entire length are aligned to carry the dust directly toward the Boise

- Nampa area. The
BRP is a dr y alkali lakebed remnant of the Pleistocene epoch Lake Lahontan that covered much
of northwest Nevada approximately 15,000 years ago (Adams and Sada 2010) . Numerous other playas in the area, including C SP

, are also remnants of Lake Lahontan

. They presumabl y haveRequest for Concurrence PM 10 Exceptional Events

10 

### similar mineral composition and are likely to also contribute to the dust reaching southwest Idaho, including during the February 15

– 16 event. Thus, it is clear that BRP , CSP

, and other playas are natural, having originated before modern human habit ation in the area. Section 2.3
show s that these playas are not significantly altered by modern human activities.



## 2.2 Source Area Wind Speeds

EPA will generally accept 25 mph as a high wind threshold as stated in the May 2013 interim guidance on high wind exceptional events (EPA 2013) :

The high wind threshold is the minimum threshold wind speed capable of overwhelming reasonable
controls on anthropogenic sources (i.e., significant emissions from controlled sources) or causing emissions
from natural undisturbed areas. The EPA recommends that air agencies establish area

- specific high wind thresholds based on local or applicable conditions and information. If an agency is u nable to develop an

area

- specific high wind threshold, the EPA will generally accept a threshold of a sustained wind of 25 mph for areas in the West provided the agencies submit evidence of this as the level at which they expect stable surfaces (i.e., controlled anthropogenic and undisturbed natural surfaces) to be overwhelmed.



### However, f

or extremely flat surfaces with disturbed or loose fine surface soils, the literature suggests that steady winds over 15 mph may cause blowing dust (Ginoux et al. 2012 ; Argaman
et al. 200 6 ). This is consistent with t he 22 mph wind speed that occurred when DEQ photographed a large turbulent dust storm on CSP

. Together, the literature and DEQ observation
establish an area

- specific wind threshold range for entraining fine playa dust from 15 to 22 mph.

Wind s peeds in Nevada on February 14

– 16 , 2011, are shown in Figure 5 and provided in detail
in Appendix B along with station identificat ion and quality control information. All wind data were obtained from MESOWEST (Horel et al. 2002), which gathers data from meteorological networks throughout the west

. Measured sustained w inds at the southwest end of BRP (BLUN2)

, northeast of BRP (TR730), and at Lovelock, N evada , in the vicinity of the CSP (KLOL)
exceeded 28 mph on February 15 ( Figure 5 ) , reaching 35 mph at the TR730 station north of the

BRP a nd 31 mph at Lovelock, near the CSP. Th e se 1

- hour sustained wind speeds are well above the 15 mph sustained wind threshold established in the literature for extremely flat surfaces such

as playas, above the 22 mph site

- specific level documented when DEQ ph otographed turbulent
dust clouds on the CSP and above the EPA default windspeed (25 mph) for natural undisturbed
areas in the west. Wind gust speeds exceeded 30 mph at all the source region sites and reached or exceeded 45 mph at two of them (KLOL and TR73 0).



## 2.3 Basic Controls Analysis

Human activities that occur on the B RP includ e recreational vehicle traffic, gypsum mining

, and periodic large but temporary gatherings such as amateur rocketry launches

. T he largest event, the annual Burning Man performance ar t festival is held at a temporary Black Rock City o n the last week of August of each year. T he Burning Man f estival disturbs only about 1% of the playa surface (BLM 2012). Together with all other human activities

, up to 7% of the playa surface is estimated to be disturbed by humans each year. However, the BLM concludes in the 2012 Environmental Assessment for the Burning Man 2012

– 2016 Special Recreation Permit (BLM 2012) that the weathering process es that occur in the fall and winter following the Burning Man
f estival “promote the formation of a surface crust on the playa, which would decrease the abilityRequest for Concurrence PM 10 Exceptional Events

11 

### of the winds to move dust.” If the human

- disturbed playa surface contributed in any significant manner to dust from the BRP, the dust impacts woul d be expected to occur near the end of the summer during or shortly after the Burning Man festival when human disturbance peaks, rather
than 6 months later in February. The winter season sees a minimum of human activity, due to harsh winter conditions, so the February 14

– 16 dust storm is not likely to be related to human activity. In addition, if human activity related to the Burning Man event was the primary cause of dust generation, the large turbulent dust clouds visible from space would be restricted to that
location near the left

- central portion of the BRP where Black Rock City is located and would not occur so broadly on the BRP and on the CSP, as seen in section 4.1

, Figure 17

. In conclusion, the dust storm of February 14

– 16, 2011 is a natural event with very little if any contribution from human activity.

R egardless of the conclusion that the February 14

– 16, 2011

, dust storm is a natural event

, it is
also clear that even if human activity did contribute to a portion of the wind erosion on the playa during this event , making it in a small part not a natural event, such human activity would be beyond the State of Idaho’s jurisdiction

, and for the purposes of the EER demonstration and
Idaho ’s responsibility, the event would still remain not reasonably controllable or preventable (nRCP)

.



# 3 In Excess of Historical Fluctuations (HF )

Analysis and observations showed that high winds may create dust storms and elevate PM 10 

### concentrations in the Boise

- Nampa area but not often. Table 1 shows the sta tistics of the PM 10 

### concentration at the Boise F S and Nampa F S monitors during the 10

- year period from 2002 through 2011 (EPA 2012). The mean annual 24

- hour PM 10 

### concentration s are 22.9 and 24.5 μg/m 3 

### at Boise and Nampa, respectively

Table 1 . Statistics of 24

- hour PM 10 concentrations recorded in Boise and Nampa

, 2002

– 2011.

Statistics Boise Nampa

Mean PM 10 c oncentration (μg/m 3 ) 22.9 24.5

Median PM 10 c oncentration (μg/m 3 ) 21.0 20 .0

Mode PM 10 c oncentration (μg/m 3 ) 14.0 15 .0

Standard d eviation (μg/m 3 ) 13.7 17.1

Count 3

, 325 2

, 852

Notes: Micrograms per cubic meter (μg/m 3 )



## 3.1 Time S eries for the P revious Ten Y ears

High wind e vents usually last a short time. Therefore, the impact on the 24

- hour average PM 10 

### concentrations is very limited most of the time. Figure 7 and Figure 8 show the 24

- hour PM 10 

### concentrations from 2002 through 2011 at Boise and Nampa . There were only two days in which
the PM 10 

### concentrations were higher than 120 μg/m 3 

### in Boise (Feb ruary 15 and 16, 2011), and five days in Nampa (including Feb ruary 15, 2011)

. Days in which the PM 10 

### exceeded 120 μg/m 3 

### (an arbitrary break point for discussion only) are identified along with the maximum 1

- hour windRequest for Concurrence PM 10 Exceptional Events

12 

### speed and 2

- minute gust speed, recorded at the Boise a irport for that day. These graphs indicate
that local wind spe eds over 30 mph and gusts over 40 mph are typically required in order for local dust sources to produce concentrations approaching the standard

— speeds well above those recorded at Boise Air Terminal (KBOI) on February 15. Higher winds did occur on February 16,
however

, those winds did not generate the dust ; they occurred after 0 8 00 MST an d served to
blow the dust out of the valley, ending the high PM 10 

### event.

Figure 9 and Figure 10 show the 24

- hour PM 10 

### concentrations at Boise and Nampa monitoring
site s respectively , along with maximum daily 1

- hour wind speeds, measured at the Boise airport, from 2002 through 2011. In these plots the wind speeds (red line ) and paired 24

- hour PM 10 

### concentrations (blue dots ) were sorted from highest to lowest wind speed to demonstrate that
when the maximum 1

- h ou r wind speed is below about 30 mph, the general pattern does not show
any apparent correlation between maximum wind speeds and PM 10 

### concentrations , and PM 10 

### concentrations never exceed 120 μg/m 3 

### (an arbitrary dividing point between normal fluctuations and extreme events)

. If the traditional local dust sources were a problem in the Boise

- Nampa area, many more of the PM 10 

### concentrations in Figure 9 and Figure 10 would increase on the far left as the highest winds occur.

Figure 11 and Figure 12 show PM 10 

### concentration distributions for Boise and Nampa, respectively. Both fig ures show that all the 24

- hour average PM 10 

### concentrations over 1 2 0 μg/m 3 

### are isolated from the main distribution range. These dis tributions indicate that the February 2011 exceedance days are exceptional with respect to the sample distribution over the pr evious
10 years.

Figure 7

. Historical PM 10 f luctuations at Boise f ire s tation no. 5 , 2002

– 2011. Values over 120 μ g/m 3 are identified by date along with the maximum 1

- h ou r w ind speed/ g ust s peed for that day.Request for Concurrence PM 10 Exceptional Events

13 Figure 8

. Historical PM 10 f luct u ations at the Nampa f ire s tation, 2002

– 2011. Values over 120 μ g/m 3 are identified by date along with the maximum 1

- h ou r w ind speed/ g ust s peed for that day.

Figure 9

. PM 10 concentration (blue dots) and paired maximum daily 1

- hour wind speed ( = SKNT

, red line ) at the Boise f ire s tation , sorted by decreasing wind speed with the highest wind speeds
to the left

. The o range box es indicate the February 15 and 16

, 2011

, exceedance s . The wind speeds were measured at the Boise airport

. N ote that the high wind on Feb ruary 16 occurred after
the event when a cold front blew the dust out.Request for Concurrence PM 10 Exceptional Events

14 Figure 10 . Daily mean PM 10 concentration (blue dots) and paired 1

- hour maximum wind speed ( = SKNT , red line ) at Nampa f ire s tation sorted by decreasing wind speed with the highest wind speeds to the left

. The o range box indicates the February 15, 2011

, exceedance.

Figure 11

. PM 10 concentration distribution

, 2002

– 2011

, at the Boise f ire s tation

.Request for Concurrence PM 10 Exceptional Events

15 Figure 12

. PM 10 concentration distribution, 2002

– 2011

, at the Nampa f ire s tation

.



## 3.2 Percentile of C oncentration s

The exceptional concentrations on February 15 and 16, 2011

, of 183 and 156 μg/m 3 

### respectively, are the highest and second highest values recorded at the Boise F S in the 10

- year dataset from
2002 to 2011. The February 15, 2011

, concentration of 174 μg/m 3 

### at the Nampa F S was the second highest in the 2002

– 2011 annual dataset, just 1 μg/m 3 

### lower than the highest value (175 μg/m 3 

### ) recorded on October 29

, 2003. The percentile statistics for these values relative to
the annual dataset for 2002

– 2011, and the 2002

– 2011 seasonal winter (D ecember, J anuary, and

F ebr uary ) data set are summarized in Table 2

. The percentiles with and without all high wind days are also shown. For the analysis summarized in Table 2

, h igh wind days are defined as days
with at least 1 hour in which the wind speed exceeded 25 mph, as recorded at the Boise a irport ’s
National Weather Service (NWS) station, KBOI. Finally, in the last column

, the percentile ranking for each February exceed a nce is shown relative to the set of only the high wind days from 2002 through 2011 ( days with max imum 1

- hour wind speed > 25 mph). In comparison, the daily maximum 1

- hour wind speed of 20.7 mph on February 15 at 1000 MST, was the 83rd percentile value for the 10

- year period, with 61 0 of 3

, 647 days having a higher maximum hourly
wind speed. This demonstrates the disconnect between this event and local winds.

It is cl ear from these statistics that the extreme PM 10 

### concentrations observed February 15 and 16, 2011

, are exceptionally high amongst any subset of Boise and Nampa data, largely independent of season or wind conditions in the Boise

- Nampa area.Request for Concurrence PM 10 Exceptional Events

16 Table 2

. Percentile statistics with respect to annual and seasonal datasets, with and without high wind days, 2002

– 2011.

Site Date PM 10

( μg/m 3 ) Percentile Relative to

Annual
Data a Annual D ata

without High Wind Days (> 25 mph) b Winter

Season
Data c Winter D ata

without High Wind Days (> 25 mph) d All High Wind

Days with
Max imum
1

- h our Wind Speed ( > 25 mph ) e

Number of Boise fire
station o bservations 3

, 322 3

, 112 809 769 208

Boise f ire

s tation 2/15 183 99.970% 99.968% 99.88% 99.87% 99.52%

Boise f ire

s tation 2/16 156 99.940% 99.936% 99.75% 99.74% 99.52%

Number of Nampa fire
station o bservations 2

, 820 2

, 647 757 724 173

Nampa f ire

s tation 2/15 174 99.18% 99.96% 99.87% 99.86% 98.84%

Notes : Particulate matter 10 micro meters or smaller (PM 10 ); micrograms per cubic meter ( μg/m 3 ); miles per hour (mph)

a

. Annual data includ ing all observations

, 2002

– 2011
b

. Annual data excluding all days with the maximum hourly wind speed above 25 mph

c

. Winter data includ ing all observations in December, January

, and February, 2002

– 2011
d

. Winter data excluding all days with the maximum hourly wind speed above 25 mph

e

. High wind days includ ing the 2002

– 2011 annual dataset after removing all days with a maximum daily 1

- hour wind speed less than 25 mph



# 4 Clear Causal Relationship (CCR)

4.1 Occurrence and Geographic Extent of the Event

Occurrence

— The dust that settled on the Boise

- Nampa area on February 15 , 2011, arrived briefly from 0 8 00 to 10 00 MST , and then again in the evening when it was trapped until the cold
front b l e w it out of the area around 0800 to 0 9 00 MST the morning of February 16. Since the area was dark for most of that time, the haze was not widely noticed beyond the NWS w eather observations indicating haze and not reported in the media other than to report the DEQ advisories (Appendix F). NWS entries identifying the haze are provided in Appendix B

.
Geographic Extent

— The geographic extent of the event can be seen in the PM 2.5 

### concentration pattern represented in Figure 6

. The dust was composed of 8 2 %

– 9 6 % coarse particles (2.5

– 10 μm in size) and onl y 4 %

– 18 % in the fine mode, less than 2.5 μm in aerodynamic diameter

. So

PM 2.5 

### levels are not as extreme as PM 10 

### levels, however DEQ operates mostly PM 2.5 

### monitors so

PM 2.5 

### is used as a surrogate for PM 10 

### to show the spatial concentration patterns. Figure 6 shows that the highes t particulate conce ntrations occurred at Nampa and Meridian on February 15 and 16 but also reached the cities of Idaho City and Garden Valley in the mountains to the north of
the Boise

- Nampa area . Finally, the Hells Canyon IMPROVE site appears to also have beenRequest for Concurrence PM 10 Exceptional Events

17 

### impacted on February 14 (Appendix C), however

, IMPROVE samples were not collected on February 15 or 16.

MODIS Satellite Evidence

— MODIS ( Moderate Resolution Imaging Spectroradiometer ) satellite imagery of the source area (NOAA 2013 ) confirms that major dust plumes were generated over the BRP and CSP areas on February 14 and 15, 2011

, and travelled in the
direction of the Boise

- Nampa area of southwest Idaho. The playa areas can be seen without significant dust generation on the mornin g of February 14, 2011 ( Figure 13 )

, which shows a MODIS true color image from the Terra satellite taken at approximately 1030 PST

.
The increasing winds on February 14, 2011

, began to generate significant dust clouds i n the afternoon, as seen in the MODIS Aqua satellite image shown in Figure 14 taken around
1330 PST. Turbulent dust clouds can be seen on the BRP and CSP, and white ha ze is visible trailing toward the northeast. The dust eroded from the BRP and CSP on February 14 first
arrived in the Boise

- Nampa area on February 14 around 18 00 to 19 00 MST , peaking around
22 00 MST as seen in the time series chart in Figure 4 ( a ). Although the hourly PM 10 

### concentration nearly reached 300 μg/m 3 

### on the evening of February 14, the 24

- hour concentration was only 55 μg/m 3 

### at the Boise F S monitor and 68 μg/m 3 

### at the Nampa FS
monitor , so the NAAQS was not threatened and exceptional event concurrence is not requested. Nevertheless, the dust impact on February 14 is important to note, because the only National
Core ( NCORE ) air monitoring net work PM 2.5 

### speciation samples collected during this 3

- day wind episode, were collected on February 14. PM 2.5 

### reached 24

- hour levels around 25 μg/m 3 

### on this day at Nampa and Idaho City , well above the levels typical for this time of year. The February 14 sp eciation is discussed in s ection 4.6

.
On February 15

, dust entrainment on the BRP and CSP started earlier in the day and can be seen
in the ~1030 PST MODIS Terra image ( Figure 15 ) , already streaming to the north ea st from the BRP and other smaller dry lakebeds and crossing the Nevada

- Oregon border. By the time the
afterno on MODIS Aqua image was taken ( Figure 16 ) , dust again stream ed to the northeast, and
turbulent puffy dust clouds are visible on both the BRP and CSP. To verify that t he puffy clouds on the BRP and CSP are dust rather than water vapor condensation clouds

, f alse c olor magnifications of the February 15 afternoon MODIS image are shown for the BRP (left side of Figure 17 ) and CSP (right side of Figure 17 ). P uffy

, white

- tan turbulent dust clouds can be seen on both playas, distinct from the blue

- tinted moisture clouds in the area and are reminiscent of the dust clouds photographed by DEQ ( Figure 3 ) near the CSP in March 2012.Request for Concurrence PM 10 Exceptional Events

18 Figure 13

. MODIS true color image from the Terra satellite, captured at ~1030 PST on Feb ruary 14,
2011

.Request for Concurrence PM 10 Exceptional Events

19 Figure 14

. MODIS Aqua image captured at ~1 3 30 PST on Feb ruary 14, 2011

.Request for Concurrence PM 10 Exceptional Events

20 Figure 15

. MODIS true color image from the Terra satellite, captured at ~1030 PST on Feb ruary 15,
2011

.Request for Concurrence PM 10 Exceptional Events

21 Figure 16

. MODIS Aqua image captured at ~1 3 30 PST on Feb ruary 15, 2011

.Request for Concurrence PM 10 Exceptional Events

22 Figure 17

. MODIS Aqua false color images (clouds and snow are blue

- tinted ; dust is white) showing turbulent dust cloud generation on Black Rock Playa (left) and Carson Sink Playa (right) as well as dust plumes leaving the playas toward the northeast ~1 3 30 PST February 15, 2011.



## 4.2 Description of W eather C onditions that C reated the E vent

Antecedent Conditions

— As described in s ection 1.3 , precipitation in the weeks prior to a wind

event produces loose, highly erodible evaporite minerals on the surface of certain alkali playas
such a BRP and CSP

. Once loose materials are present on the surface

, wind gusts may initiate saltation of small particles. Daily precipitation data at sites in the BRP and CSP source region for the period from January 1 th rough February 15, 2011, are shown in Figure 18 and are provided
in tabular form in Appendix B. Rain fell at Lovelock and Fallon, near the CSP and north of the

BRP (TEXN2) on January 30

, two weeks prior to the event

, and relatively heavy rains fell at all sites around the BRP (BUFN2, BLUN2, TR730 and TEXN2) between January 12 and 16, 2011, four weeks prior to the event. The t wo weeks prior to the event were dry at al l stations except for TEXN2, a higher ele vation station north of the BRP

, which received 0.07 inches on February 5

, still leaving nine days for drying and surface evaporite formation. DEQ believes that these precipitation patterns are ideal for enhancing t he near

- surface water table or moisture layer in the
weeks prior to the high wind dust event and for causing significant surface evaporite mineral
formation.Request for Concurrence PM 10 Exceptional Events

23 Figure 18

. Twenty

- four hour precipitation totals in the BRP and CSP so urce region in the 45 days prior to the event.



### Event Conditions

— Also important for dust episodes stemming from the BRP and CSP are the passage of cold fronts ( or baroclinic troughs ) and geostrophic adjustment (Steenburgh et al. 2012). A trough passe d through around 1100 MST on February 15

, 2011

, and propagate d eastward with the jet stream. This jet contribute d to a rapid rate of pressure change as the atmosphere adjust ed to geostrophic imbalance ( Kaplan et al. 2 01 0 ). It is possible to note the
marked decrease in pressure of about 1 millibar per hour (mb * 

### hr - 1 

### ) at several stations in northern
Nevada

, such as Fallon and Elko , southern Idaho, and Ontario in eastern Oregon

, associated with this passage when one compares Figure 19 and Figure 20

.Request for Concurrence PM 10 Exceptional Events

24 Figure 19

. 1800Z (11 00 MST) surface analysis February 15

, 2011 ( National Weather Service Hydrometeorological Prediction Center : http://www.hpc.ncep.noaa.gov/html/sfc_archive.shtml )

.

Figure 20

. 2100Z ( 0 2 00 MST) surface analysis February 15 , 20 11 ( National Weather Service Hydrometeorological Prediction Center : http://www.hpc.ncep.noaa.gov/html/sfc_archive.shtml )

.Request for Concurrence PM 10 Exceptional Events

25 

### High wind speeds can be observed across eastern Oregon and northwest Nevada preceding and on the event day using N ational Center for Environmental Prediction ( NCEP ) / North American Regional R eanalysis (NARR) model data ( M esinger et al . 2006

, accessed November 23, 2012
from http://www.esrl.noaa.gov/psd/ data/gridded/data.narr.html )

. The BRP lies along the edge of this boundary and experienced winds aloft of 25 m / s (56 mph) as shown in Figure 21

.

Figure 21

. NCEP/NARR m odel reanalysis of midlevel winds ( meters per second ), February 14

– 15

, 20 11 ( NOAA/ESRL Physical Science Division, Boulder Colorado : http://www.esrl.noaa.gov/psd/ )

.


### Steenburgh et al. (2012) noted that sustained winds of 10 m / s (22 mph) are strong enough to
elevate dust , while Argam a n et al. (200 6 ) and Ginoux et al. (2012) suggest that 15 mph is an appropriate threshold velocity for wind erosion on flat surfaces with disturbed or loose material

. After the morning inversion broke, th e momentum associated with this midlevel flow would have mixed down to the surface and enhanced winds related to the baroclinic trough passage. Figure 22 shows the 11 00 PST sounding information for Reno, N evada

. The figure indicates that not only had the inversion broken, but vertical mixing occurred as the temperature profile parallels the dry adiabat curve to around 690 millibar ( mb ) . At this height, another inversio n set in and prevent ed any further mixing.Request for Concurrence PM 10 Exceptional Events

26 Figure 22

. Sounding information for Reno, N evada, at 18Z (11 00 PST ) February 15 , 20 11 ( National Weather Service Upper

- Air Observations Program

- Global Climate Observing System. University of Wyoming Sounding : http://weather.uwyo.edu/upperair/ sounding.html

)

.


### Surface observations taken from stations across the desert and Great Basin on February 14 and 15, 2011

, indicate sustained wind speeds greater than 10 m /s (22 mph) for multiple consecutive hours across both days. Coupled with this were sufficiently high threshold friction velocities (TFV) . TFV values greater than 0.8 m / s are generally strong enough to erode both disturbed and undisturbed dust (Marticorena et al., 1997); however, Holcombe et al. (1997) noted th at TVF
values of 0.3

– 0.5 m

/ s are strong enough to lift disturbed particles , which are expected to be present on the playas . TFV is a measure for condit ions necessary for blowing dust and is higher
for undisturbed soils and lower for disturbed soils. Friction velocities have been calculated for 18Z February 15 (11 00 MST) using the NAM12 model. As illustrated in Figure 23

, the TFV
exceeds 0.4 m

/ s and is between 0.8 and 1.2 m / s across the source region indicating that the minimum TFV required to lift dust are met and exceeded for both disturbed and undisturbed

crust

.Request for Concurrence PM 10 Exceptional Events

27 Figure 23

. Friction velocity for 1 8Z (12 00 MST) February 15 , 20 1 2 , NARR NAM

- ANL ( Natio nal Climatic Data Center National Operational Model Archive and Distribution System

, NWS

- NCEP
NAM

, 12 km : http://nomads.ncdc.noaa.gov/data.php?name=access#hires_weather_datasets ).



### Presented with the following information, it is possible to relate observed meteorological conditions and atmospheric measurements to such a conceptual model. Observ ations taken from

M ESOWEST stations at KBOI (Boise, ID), KLOL (Lovelock, NV), and KWMC (Winnemucca, NV), provided in Appendix B, all indicate poor visibility and haze throughout the period of February 15

– 16

, 2011. Weather conditions in Boise during the eve nt promoted the containment and accumulation of particulate in the valley as a result of weak surface winds overnight and a weak surface inversion , as indicated in t he February 16, 2011

, morning ( 12Z ) sounding shown in Figure 24 taken at Boise, I daho

.Request for Concurrence PM 10 Exceptional Events

28 Figure 24

. Sounding information for Boise, I daho, at 12Z ( 0 5 00 MST ) February 16 , 20 11 ( National Weather Service Upper

- Air Observations Program

- Global Climate Observing System. University of Wyoming Sounding : http://weather.uwyo.edu/upperair/sounding.html )

.


### Winds the evening of February 15

, 2011

, ranged f rom calm to 18 mph over the time period of
1900 to 0 7 00 MST the morning of February 16

, with observations of haze from 2200 to 0 8 00
MST. At 0 9 00 MST a cold front associated with the trough axis responsible for the event passed through the area quickly remo ving any residual airborne dust . After that, conditions were reported as mostly clear as winds shifted from the southeast to the northwest, surface temperatures dropped from 48 o 

### F to 33 o 

### F

, and snow began to fall. Figure 25 indicates the position of the cold front to be slightly west of Boise, I daho, at 15Z on February 16

, 2011 ( 0 8 00 MST)

, and Figure 26 indicates the position of the cold front to be east of Boise, I daho, at 1800Z

on February 16

, 2011 ( 11 00 MST).Request for Concurrence PM 10 Exceptional Events

29 Figure 25

. 1500Z ( 0 8 00 MST) surface analysis February 16 , 20 11 ( National Weather Service Hydrometeorological Prediction Center : http://www.hpc.ncep.noaa.gov/html/sfc_archive.shtml )

.

Figure 26

. 1800Z (11 00 MST) surface analysis February 16 , 20 11 ( National Weather Service Hydrometeorological Prediction Center : http://www.hpc.ncep.noaa.gov/html/sfc_archive.shtml )

.Request for Concurrence PM 10 Exceptional Events

30 

### The observed surface winds d uring the afternoon of February 15, 2011 (1500 MST) are shown
for the N WS and United States Department of Agriculture Forest Service/B ureau of L and

M anagement remote automatic weather (RAWS) stations reporting to the MESOWEST service ( Horel et al. 2002) in Figure 27

. Winds in the source region around the playas are generally in
the 20 to 28 mph range

, and gusts reach up to 46 mph . Surface wind speeds between the BRP

an d CSP area and Boise and Nampa monitors rema in elevated but then decreas e to around
1 3 mph only after reaching the Snake River and Boise River valleys.

Figure 27

. Surface winds 1500 MST on February 15, 2011

, from MESOWEST (Horel et al. 20 02 )

. Wind b arbs point in the direction toward which the wind is blowing. Number on left of dot indicates hourly sustained wind speed

, and number on right indicates the maximum 2

- minute wind gust for that hour, both in miles per hour.Request for Concurrence PM 10 Exceptional Events

31 

## 4.3 Transport of E missions R elated to the E vent in the D irection of
the M onitor(s) W here M easurements W ere R ecorded

The transport of emissions from the source area to the monitors where the particulate measurements were recorded are shown graphically using bac k

- trajectory plots

, which begin at
the monitors at the time that the PM 10 

### levels are rising through the time that they either peak or pass. The back

- trajectories are an established methodology that utilizes archived model meteorological fields, including a wind speed and wind direction vector for every hour and every
12 km distance and links them backward in time, delineating the path that the air mass has taken in the previous 24 hours prior to its arrival at the monitor. Using this approach, whenever the suspected source area or areas occur along one or more of the back

- trajectory lines

, this is evidence linking the source area to the monitored peak concentrations, a key element demonstrating the causal relationship.

Back

- trajectories were computed using the National Oceanic and Atmospheric Administration’s ( NOAA’s ) Ready HYSPLIT modeling tool (Draxler and Rolph 2003) . The archived NAM 12 k m meteorological model was used to compute 24

- hour long back

- trajectories with modeled vertical motion, and starting elevations at 0, 50 0

, and 1

, 000 m eters aboveground level, ending at the
Boise F S monitor (which is also reasonably representative of the Nampa F S m onitor)

.
For the February 15

– 16, 2011

, dust episode, two periods of time occurred in which the dust from the playas of northwest Nevada arrived in the Boise

- Nampa area. The back

- trajectories are designed to show the origin of the winds reaching Boise at these times. These two impact periods
are visible in the PM 10 

### time series plot in Figure 4 :

 0500 to 1000 MST Feb ruary 15

— This was a smaller impact, with 1

- hour PM 10 

### concentrations in the 200 to 330 μg/m 3 

### range, but it did contribute significantly to the
recorded 24

- hour PM 10 

### concentration. The back

- trajectories for this period, shown in Figure 28 , indicate that the 500 m eter and 1

, 000 m eter trajectories pass near the BRP, closely paralleling the visible blowing dust trending toward Boise.

 1600 to 2400 MST Feb ruary 15

— This is the major impact period when dust from Nevada reached hourly concentrations around 500 μg/m 3 

### , then remained trapped in the valley overnight until the dust was advected out of the valley around 0 9 00 to 10 00 MST
on Feb ruary 16. As a result, the high PM 10 

### con centrations persisted for nearly 10 hours, exceeding the standard on both Feb ruary 15 and 16 at the Boise FS monitor and on
Feb ruary 15 at the Nampa FS monitor. The back

- trajectories for the period of rising PM 10 

### concentrations on the evening of February 1 5, 2011

, between 1600 and 2400 MST are
shown in Figure 29 . For the air mass arriving in Boise during this period, it appears that the surface level air may have passed over the CSP, while the 500 m eter and 1

, 000 m eter air passed directly over the BRP. Thus, it appears that either or both playas may have
contributed.

In summary, the back

- trajectories for the dust impact periods on February 15 and 16, 2011

, corroborate the blowing dust visible in the MODIS satellite images for t he same time frame and
are consistent with the measured surface wind directions shown in Figure 27

.Request for Concurrence PM 10 Exceptional Events

32 Figure 28

. H YSPLIT back

- trajectories from the 0500

– 1000 MST PM 10 peak at Boise

- Nampa area on February 15 , 20 11 ( NOAA Ready HYSPLIT model : http://ready.arl.noaa.gov/ HYSPLIT_traj.php

)

.Request for Concurrence PM 10 Exceptional Events

33 Figure 29

. H YSPLIT back

- trajectories from the 1600

– 2400 MST PM 10 peak at Boise

- Nampa area on February 15 , 20 11 ( NOAA Ready HYSPLIT model : http://ready.arl.noaa.gov/HYSPLIT_traj.php ).Request for Concurrence PM 10 Exceptional Events

34 

## 4.4 Spatial R elationship B etween the E vent, S ources, T ransport of
E missions, and R ecorded C oncentrations.

The spatial relationship between the wind erosion event at the BRP and CSP source areas, and the transport winds are depicted in Figure 28 and Figure 29 where back

- trajectories lead directly from the impacted are a of the Boise

- Nampa monitors to the source areas. These modeled back

trajectories are confirmed by the recorded surface observations throughout the source and transport region, depicted graphically in Figure 27 , as well as the MODIS satellite images in Figure 14 through Figure 16

, which show dust blowing from the BRP and CSP source areas directly toward the Boise

- Nampa area a long the same 210 to 230 degrees bearing (from true north).



## 4.5 Temporal R elationship B etween the H igh W ind and E levated PM C oncentrations at the M onitor(s) in Q uestion

Time series charts combining source area winds and wind directions

, and Boise

- Nampa area hourly PM 10 

### monitor data and winds are shown in Figure 4 and Figure 5

. These time series charts show high afternoon winds in the source area s in Nevada blowing dust toward the Boise

- Nampa

ar ea on the afternoon of February 14 and throughout most of the day on February 15, 2011. The
dust , indicated by PM 10 

### concentrations at Boise FS and Nampa FS monitors, peaked on February
14 at 1900

– 2200 MST, and again on February 15 at 0500

– 1000 MST and 1600

– 2400 MST

, where it appeared to be trapped by reduced wind speeds until the increasing winds associated with the cold front blew it out of the valley the following morning

.



## 4.6 Similarity of C hemical C omposition of M easured P ollution w ith

t hat E xpected f rom S ources I dentified a s U pwind

Chemical S imilarity

— The PM 10 

### monitors indicated unusually high concentrations peaking at 1900

– 2200 MST on Feb ruary 14, 2011. Although the NAAQS was not threatened

, the PM 10 

### impacts are of interest on February 14 because that is the only day of the multiday high wind episode in Nevada for which a speciation sample was collected at the NCORE speciation site
located at St. Luke ’ s Medical Center , Meridian , Idaho

, sampling location, situated between the
Boise F S and Nampa F S . The St. Luke ’ s speciation filters are routinely submitted to an EPA laboratory for extensive chemical analysis, thus providing a chemical composition for the dust.
The PM 10 

### at the Boise and Nampa FS monitor ing sites and the PM 2.5 

### at the St. Luke’s monitor ing
site all reached unusually high levels on the evening of February 14, suggest ing dust impacts

. DEQ investigated the potential sources to see if the same source mechanisms and transport conditions occurred on February 14 as DEQ documented on February 15 and 16

.
First, winds in the source areas of northwest Nevada were obtained, verifying winds around
25 mph with gusts exceeding 40 mph occurred for the entire afternoon from 1200 through 1800 MST, with additional high wind periods around 2100 and 2300 MST ( Figure 5 ). Next, MODIS satellite images were obtained showing that while visible dust was not blowing during the

~ 1030 PST MODIS Terra satellite pass ( Figure 13 ), visible dust blowing off the BRP toward the
Boise

- Nampa area was visible in the afternoon during the MODIS Aqua satellite pass at

~ 1330 P ST ( Figure 14 ).Request for Concurrence PM 10 Exceptional Events

35 

### Finally, HYSPLIT back

- trajectories were simulated, as described earlier, starting at Boise F S during the peak PM 10 

### hours

, 1900

– 23 00 MST , on Feb ruary 14 . As shown in Figure 30 , surface
level back

- trajecto r ies appear to pass over the CSP area where MODIS satellite images show vigorous puffy dust clouds indicative of turbulent wind erosion. The 500 m eter and 1

, 000 m eter trajectories pass very near the western edge of the BRP suggesting that while CSP is a very likely source, BRP is potentially also a contributing source area on February 14.

Figure 30

. HYSPLIT back

- trajectories for the Boise

- Nampa area PM10/PM2.5 impact period 2100

– 2300 MST , February 14, 2011 ( NOAA Ready HYSPLIT model : http://ready.arl.noaa.gov/HYSPLIT_traj.php )

.



### Based on the ad ditional wind speed data , satellite images, and back

- trajectories presented for February 14, DEQ concluded that the same source areas and transport conditions brought
elevated PM 10 

### and PM 2.5 

### to the Boise

- Nampa area on February 14 as was demonstrated for th eRequest for Concurrence PM 10 Exceptional Events

36 

### higher impacts observed on February 15

– 16, 2011, and therefore the chemical composition of the February 14 sample is a fingerprint of the same dust that caused the NAAQS violations on February 15

– 16, 2011.

NCORE speciation data for February 14, 2011

, is provided in Appendix D and is compared in Figure 31 to a literature composition for the BRP surface soils analysis (Gillett 1997). T he February 14 St. Luke’s PM 2.5 

### fingerprint matches the BRP surface soils composition very well ( Figure 31 ) but is slightly enriched in c alcium (Ca) and s odium (Na). These are indicators of the water soluble evapor i te minerals identified by Tollerud and Fantle (20 12)

, and their enrichment in the February 14 NCORE samples supports the conceptual model mechanism involving wind

ero sion of calcium enriched evapori te minerals (along with clays and silts) made more erodible by antecedent precipitation in the weeks prior to the event.

Figure 31

. February 14 , 2011, PM 2.5 c omposition (NCORE 2013) compared to Black Rock Playa surface soil composition (Gillett 1997)

.



### It should be noted, as anecdotal weight

- of

- evidence

, that the February 14, 2011, NCORE speciation represents the second highest geologic composition observed at the St. Luke’s NCORE site. An examination of the highest geologic component in the 2006

– 2011 database, which was recorded on November 22, 2006, ind icates a remarkably similar composition to the February 14 sample, in that the calcium content was unusually high. DEQ examined winds in Nevada on November 22, 2006, developed back

- trajectories, and concluded that the dust reaching the Boise

- Nampa area on that day, while not approaching the PM 10 

### standard in magnitude, also originated in the playa region of northwest Nevada under high wind conditions. DEQ concludes that high geologic component, enriched in calcium is a signature of the playa
dust from the BR P, CSP

, and other playas in northwest Nevada.Request for Concurrence PM 10 Exceptional Events

37 

### Size Similarity

— In addition to the chemical similarity between the dust reaching the Boise

Nampa area on February 14, 2011

, and BRP surface sediments, the size distribution provides
additional information about the nature of potential sources. Wind

- blown dust is known to be mostly larger than 2.5 μm in size, while most other sources of atmospheric particulate air pollution generate particles smaller than 2.5 μm. Smoke particles from combustion sources, including fires, residential wood combustion, gas and diesel vehicle exhaust

, and industrial combustion sources are typically smaller than 1 μm in size. Secondary organic aerosols formed by condensation of gaseous organic compounds such as terpenes or polyaromatic hydrocarbons are also less than 2.5 μm in size. Finally, secondary inorganic aerosol species including ammonium nitrate and ammonium sulfate, formed when nitrogen oxides and sulfur oxides oxidize in the atmosphere and combine with ammonia are less than 2.5 μm

. Careful examination
of PM 2.5 

### and PM 10 

### hourly concentrations in Figure 4 indicates that the PM 10 

### dust that arrived on February 15 was composed of approximately 4 % to 18 % PM 2.5 

### ( the remainder, 8 2 % to 9 6 % was in the coarse particle fraction , 2.5 to 10 μm in size)

.
Analysis of historical PM 2.5 

### / PM 10 

### ratios data suggests that the event of Feb ruary 14

– 16, 2011

, was a dust event. Figure 32 shows the PM 2.5 

### / PM 10 

### ratio measured at the Nampa F S monitoring
site in winte r months over the previous 2 years (red line) sorted by increasing the PM 2.5 

### / PM 10 

### ratio , along with the paired 1

- hour PM 10 

### concentration (blue squares). The data show that for the all samples with PM 10 

### hourly concentration s higher than 100 μg/m 3 

### , the PM 2.5 

### / PM 10 

### ratio is
lower than

~ 0.2 (or 20%)

, indicating that the main component is coarse particulates

, the character of dust particles, while the majority of winter hours have more than 20% PM 2.5 

### indicating that they consist largely of smoke and secondary aer osol species typical of a winter speciation

. Table
3 shows that 18 of the 25 highest hourly PM 10 

### concentrations (greater than 100 μg/m 3 

### ) in the
winter 201 0 and 201 1 d ataset at the Nampa FS (circled red in Figure 32 ) were measured during
the Feb ruary 14

– 16 event

. The other seven hourly PM 10 

### concentrations above 100 μg/m 3 

### occurred on days when the Boise airport winds were in the 22

– 25 mph range with gusts from 32 to 39 mph

, all higher than the winds recorded during the February 15 event. These non event hourly observations reflect local dust transported a much shorter distance, allowing less of the larger particles to settle out, therefore having a more coa rs e composition and a lower

PM 2.5 

### /PM 10 

### ratio. The 24

- hour average s that included the other hourly values never exceeded
48 μg/m 3 

### at the Nampa FS or 21 μg/m 3 

### at the Boise FS

, more typical of windy winter days where
local sources dominate. In conclusion, the size information demonstrates that there is very little contribution from sources of fine particulate (PM 2.5 

### ) during the event, such as car exhaust, burning, industrial combustion

, and secondary aerosol formation but a somewhat greater

PM 2. 5 

### / PM 10 

### ratio than expected during high wind dust storms originating from local sources.Request for Concurrence PM 10 Exceptional Events

38 Figure 32 . PM 2.5

/ PM 10 ratio at the Nampa fire station sorted from low to high (red line, left axis)

v er s us paired 1

- h ou r PM 10 c oncentration (blue dots)

. Hourly values above 100 μ g/m 3 that occurred during the Feb ruary 14

– 16 event are circled in red

Table 3

. Hourly PM 10 concentrations greater than 100 μg/m 3 at the Nampa fire station for winter
2010 and 2011 only. Values related to this dust event are shown in bold (red circles in Figure 32 ).

Date Hourly

PM 10 (μg/m 3 ) Date Hourly
PM 10 (μg/m 3 ) Date Hourly
PM 10 (μg/m 3 )

1/19/2011 101 2/15/2011 141 2/16/2011 260

2/14/2011 285 2/15/2011 117 2/16/2011 202

2/14/2011 181 2/15/2011 103 2/16/2011 169

2/14/2011 151 2/15/2011 103 11/1/2011 139

2/15/2011 282 2/15/2011 101 11/3/2011 116

2/15/2011 231 2/16/2011 532 12/2/2011 339

2/15/2011 179 2/16/2011 328 12/2/2011 147

2/15/2011 162 2/16/2011 264 12/21/2011 282

— — — — 12/21/2011 228

Notes : Particulate matter 10 micro meters or smaller (PM 10 ); micrograms per cubic meter (μg/m 3 ).



### Difference in C omposition from T ypical Boise

- Nampa A erosol

— The NCORE speciation sample captured on February 14 incl udes approximately 5 hours of elevated dust impacts
attributed to the BRP and CSP wind erosion source, while the remainder of the day exhibits
somewhat normal PM 10 

### and PM 2.5 

### concentrations, based on the time series chart presented inRequest for Concurrence PM 10 Exceptional Events

39 

### Figure 4 . DEQ transformed the NCORE speciat ion into the routine classifications of fine particulate matter (< 2.5 μm): e lemental c arbon (EC)

, o rganic c arbon (OC) , ammonium sulfate ( (NH 4 

### ) 2 

### SO 4 ) 

### , ammonium nitrate ( NH 4 

### NO 3 

### ) , and geologic ( G EO) as shown in Table 4

. The fine particulate matter in western cities is usually classified into these five categories and their sum should approximate the total PM 2.5 

### mass.

In addition to the February 14 composit ion, Table 4 shows that the average composition of the
Boise

- Nampa airshed averaged over 2009

– 2011

, which is typically dominated by organic matter
and ammonium nitrat e, a secondary aerosol pollutant formed from photochemical reactions of nitrogen oxides to form nitrates and combine with ammonia. The winter speciation is similar to the annual speciation, with the exception that the ammonium nitrate is much higher and th e geologic component is generally lower . On February 14, the ammonium nitrate and organic matter were lower than usual, and the geologic portion of the PM 2.5 

### was much higher, comprising 37.7% of the mass, 10 times higher than the normal geologic compositio n in winter (3.7%)

. M ost of the geologic particulate mass probably arrive d mostly during 5 hours on the evening of February 14 when the PM 10 

### peaked , w hile the remainder of the hours on tha t day apparently contributed organic matter and smaller amounts of o ther species reflective of near
normal wintertime speciation.

Table 4

. Comparison of February 14 St. Luke’s monitoring site PM 2.5 composition with the annual average and winter season historical compositions, 2009

– 2011.

Feb ruary 14, 2011

, 24

- hour Speciation Sample
Species OM EC (NH 4 ) 2 SO 4 NH 4 NO 3 G EO PM 2.5
Concentration ( μg/m 3 ) 1.4 0.2 0.3 0.3 2.3 6.1

% 22.7 % 4.0 % 5.2 % 5.7 % 37.7 %

3

- year Annual Average Speciation, 2009

– 2011
Species OM EC (NH 4 ) 2 SO 4 NH 4 NO 3 G EO PM 2.5
Concentration ( μg/m 3 ) 2.8 0.4 0.7 1.4 0.7 7.1

% 41.2% 5.4% 10.1% 20.7% 10.5%

—
3

- year Winter Average Speciation, 2009

– 2011
Species OM EC (NH 4 ) 2 SO 4 NH 4 NO 3 G EO PM 2.5
Concentration ( μg/m 3 ) 3.8 0.5 1.1 3.4 0.3 9.4

% 41.3% 5.3% 12.3% 36.3% 3.7%

—

Notes : Organic carbon (OC); elemental carbon (EC); ammonium sulfate ( (NH 4 ) 2 SO 4 ); ammonium nitrate ( NH 4 NO 3 ); geologic (GEO); particulate matter 2.5 micro meters or smaller (PM 2.5 ); micrograms per cubic meter ( μg/m 3 )Request for Concurrence PM 10 Exceptional Events

40 

## 4.7 Comparison of E vent

- A ffected D ays to S pecific N o nevent D ays

— C omparison of Area C oncentrations and W ind S peed s in the
D ays P receding and F ollowing the E vent

The high wind s over the playas of northwestern Nevada lasted from about noon on February 14 through the afternoon on February 15, 2011

, and affected the Boise

- Nampa area PM 10 

### concentrations on February 14, 15

, and 16. The elevated PM 10 

### concentrations on these three days at the Boise FS and Nampa FS monitors are compared to the nonevent days before and after the
event in Figure 33 . This figure shows that the normal winter season PM 10 

### concentrations are typically around 10

– 30 μg/m 3 

### even when the local winds are higher than those experienced on February 14 and 15 when the dust was transported to the area. The high wind speed on Febru ary 16 is not associated with the dust event that persisted through the early morning hours but
occurred later on that day when the cold front moved through the valley after about 0800 MST effectively blowing the dust out of the valley. Finally, i t appears obvious from Figure 33 that the
elevated PM 10 

### concentrations on February 14 and 16 were also part of the same multiday wind event that peaked on February 15 alt hough they are not included in this exception request.

Figure 33

. Event

- affected days along with nonevent days before and after the February 14

– 16,
2011

, event.



## 4.8 Alternative Hypotheses

The analysis presented in this report demonstrates that the elevated PM 10 

### particulate matter impacting the Bo ise and Na mpa FS monitors is composed of over 82 % of coarse particulate (larger than 2.5 μm and smaller than 10 μm), predominately geologic in composition with some enrichment in evaporite mineral constituents calcium and sodium. Very little elemental carb on,Request for Concurrence PM 10 Exceptional Events

41 

### ammonium sulfate

, and ammonium nitrate particulate is present as is common in many wintertime western urban airsheds, including the Boise

- Nampa airshed ( s ection 4.6 ). It is therefore clear that the normal urban sources such as residential wood combustion, vehicle
exhaust , industrial combustion

, and outdoor burning are not contributors to any significant

extent , but rather, the source is geologic in nature. In add ition

, the lack of significant elemental carbon, along with the timing in the winter season indicate that neither wildfires nor agricultural
fires contributed to the PM 10 

### levels during this event.

Potential geologic particulate sources include road dust, construction dust, industrial emissions, agricultural dust

, and wind erosion from nonagricultural lands, either those surrounding the
Boise

- Nampa area, or regional sources located outside the Treasure Valley of Idaho. All these potential sources are inhere ntly included in the statistics for the previous 10 years provided in
Section 3

, “In Excess of Historical Fluctuations ” and Section 7

, “ No Exceedance But For This

Event

, ” and therefore are already excluded as probable sources since

, historically , they rare ly produced concentrations as high as those recorded on February 15 and 16. Nevertheless, DEQ
considered each of these source s a s a potential source category for coarse geologic dust and
discusses each below

.

 Road D ust

— Road dust emissions vary with the qu antity of fine particles or silt on the roadway and the amount of vehicle traffic. The quantity of silt varies with season and is typically higher in the winter due to antiskid road sanding operations. However, road sanding agreements and cleanup documente d in the Northern Ada County PM 10 

### State Implementation Plan ( SIP ) (DEQ 2004) provide reasonable control of silt loadings resulting from winter antiskid treatment

. In addition, the period from January 1 through February 15, 2011, just prior to this event, h ad the second lowest snowfall of any January 1

– February 15 period in the previous 10 years, so road

- sanding

- related silt on the road should have been lower than most of the years included in the PM 10 

### statistics
described in s ection 3.1

.

 Construction D ust

— No major new construction projects were in progress in the vicinity
of either the Boise F S or Nampa F S monitors in February 2011. February i s also generally too early in the spring for any significant new construction elsewhere in the valley. Finally, it is unlikely that a location

- specific source category such as construction would affect both sites similarly, not to mention the Idaho City an d Garden Valley sites
in the mountains to the north.

 Industrial E missions

— Idaho’s New Source Review P ermitting P rogram limits industrial emissions. Air quality permits for 13 significant sources of dust were revised to limit
allowable PM 10 

### emissions in the 2004 Northern Ada County PM 10 

### S IP (DEQ 2004). Thus, a decline in allowed industrial particulate emissions has occurred over the last
10 years, and no sudden increase in industrial emissions appears to have occurred that is large enough to reach the dust l evels observed during this event.

 Agricultural A ctivity

— Agricultural areas surround the cit y of Nampa and are not too far from the city of Boise and are a potential source of fugitive dust from tilling and harvesting or from wind erosion from bare fields t hat have been recently disturbed. Harvesting in the Treasure Valley occurs in the f all with the last harvest date for any major Idaho crop ending by November 10, while the earliest planting date for any major Idaho crop is March 21 (USDA 2010). Thus, soil

- disturbing agricultural activities are at a minimum level in the winter, and 3 mon ths of wintertime weather sh ould serve toRequest for Concurrence PM 10 Exceptional Events

42 

### minimize the freshly disturbed surface amenable to wind erosion. Finally, wind speeds at the Boise a irport did not exceed 21 mph on February 1 5 , so significant wind erosion from agricultural land is not likely to have contributed noticeably to the PM 10 

### concentrations during this event.

 Nonagricultural L ands

— The winds in the Boise area during this event did not exceed
2 1 mph, wi th gust s no greater than 25 mph, much lower than other wind storms over the
last 10 years that never produced PM 10 

### concentrations approaching the standard

, so it is very unlikely that natural, nonagricultural lands such as desert and rangeland in Idaho
contribute d significantly to the dust events of February 14

– 16, 2011.

Alternative source categories such as those described above are generally already characterized
in the normal PM 10 

### historical fluctuations ( s ection 3) over the past 10 years, and no significant

va riation in any of these source categories is known that could cause an extreme PM 10 

### episode of the magnitude and geographic extent observed February 14

– 16, 2011.



# 5 Affects Air Quality (AAQ)

The EER requires agencies to document that the identified source of an exceptional event truly affected air quality at the location of the monitor in question. However, EPA’s i nterim h igh w ind

g uidance (EPA 2013) indicates that if h istorical f luctuations (HF) and a c lear c ausal r elationship (CCR) have been adequately demonstrated, then the affects air quality ( AAQ ) element will have
been met.

The PM 10 

### concentrations reached at the Boise F S on February 15 and 16 , 2011, exceed any reached in the previous 10 years, far exceeding all normal historica l fluctuations ( section 3). Similarly, the February 15 PM 10 

### concentration at the Nampa F S monitor exceeded all but one value in the previous 10 years demonstrating both sites exceeded normal historical fluctuations

. In addition, a clear causal relationship has been demonstrated through back

- trajectories, satellite images

, and composition, linking dry lake beds in Nevada to these events ( s ection 4). Therefore the high wind events originating at the B RP and/or C SP in Nevada clearly affected air quality at
the Boise FS and Nampa FS monitor ing sites on February 15 and 16

, and DEQ has satisfied the
affects air quality criterion.



# 6 Natural Event or Human Activity Unlikely to Recur at the Same Location ( NE/ HAURL )

The EER requires agencies to document that the identi fied source of an exceptional event is
either a natural event (NE) or a human activity unlikely to recur at the same location (HAURL)
and affect s the monitors in question again. However, EPA’s i nterim h igh w ind g uidance (EPA 2013) indicates that if an agency has adequately demonstrated that the source is a natural event or, if not natural, is not reasonably controllable or preventable and that there is a clear causal relationship between the identified source and the affected monitor, then the natural event/ human activity unlikely to recur at the same location criterion is also satisfied.Request for Concurrence PM 10 Exceptional Events

43 

### DEQ demonstrated in s ection 4 that there is a clear causal relationship between the BRP and CSP
source areas in Nevada and the extremely high PM 10 

### levels at the Boise FS and Nampa FS monitors on February 15 and 16, 2011. DEQ showed in s ection 2 that these Pleistocene

- era dry lakebeds are not only natural sources, with a natural dust generation mechanism minimally influenced by hum an activity, but also that even if human activity was considered significant enough to term the playa emissions in some small part not n atura l , Idaho has no control over any human activity occurring on f ederal lands in another state

, and therefore from an Idaho perspective, the source would remain not reasonably controllable or preventable.



# 7 No Exceedance But For this Event (NEBF)

The EER 40 CF R 50.14(b)(1) directs EPA to exclude data only where an agency demonstrates an exceptional event caused a concentrat ion in excess of a NAAQS. It must be shown that the
concentrations at the monitor would have been below the standard if the event had not occurred (i.e.

, but for the event)

.
EPA guidance (EPA 2013) suggests that i f nonevent pollution levels are typically significantly below the NAAQS during the season of the event

, then a qualitative no exceedance but for ( NEBF ) may be adequate. The very low 95 th and 99 th percentile values in Table 5 demonstrate that this is the case. The discussion of particle size in s ection 4.6 demonstrating that fire and secondary aerosol cannot be responsib le, and the discussion of alternative local dust sources in

s ection 4.8 demonstrate qualitatively that no other local sources could cause PM 10 

### concentrations
as hi gh as those recorded during this event. A quantitative no exceedance but for analysis is provided below in addition to the qualitative d iscussion.

Quantitative N o E xceedance B ut F or A nalysis

— The clear causal relationship with the Nevada playas has already been established in s ection 4

. Table 5 shows the PM 10 

### concentrations at the Boise FS and Nampa FS monitoring sites representing the average, 95th and 99th percentile
concentration values for historical annual and winter season monitoring data , 2002

– 2011 . While
the m ost probable upper end of the range of concentrations expected at Boise FS and Nampa FS
monitors may be represented by the average and 95 th percentile values (EPA 2013 ), DEQ will assume that the normal background fluctuations could have been as high as the 99 th percentile
historical value , to be conservative.

The statistics shown in Table 5 indicate that the normal year

- round concentration s at the Boise

F S

, but for the BRP and CSP playa dust on Feb ruary 15 and 16, 2011

, would have been at or below the range 23

– 45 μg/m 3 

### and 99% of the time it would have been 66 μg/m 3 

### or less. The
Boise F S concentrations on February 15 and 16 were 183 μg/m 3 

### a nd 156 μg/m 3 

### , respectively, so it is clear that the playa dust contributed at least 117 μg/m 3 

### on February 15 (183 − 66 = 117 ) and
90 μg/m 3 

### on February 16 (156 − 66 = 90 ). Thus, the event contributed more than half the PM 10 

### on these two days

, and it is clea r that the NAAQS (150 μg/m 3 

### ) would not have been exceeded but for the regional transport event from the playas as described in this document.

A t the Nampa F S , the normal concentrations, but for the BRP and CSP playa dust would have been in the range 24

– 56 μg/m 3



### , and 99% of the time, it would have been less than 78 μg/m 3



### based on the annual values in Table 5 . Again, it is clear, that at the Nampa F S , over half the PM 10 

### concentration of 174 μg/m 3 

### measured on February 15 resulted from the regional playa dust eventRequest for Concurrence PM 10 Exceptional Events

44 

### and that at least 96 μg/m 3 

### (174 − 78 = 96 ) or 55% of the February 15 concentration may be attributed to the playa dust. Therefore, the NAAQS would not have been exceeded on that day but for the regional transport event from the playas.

The seasonal statistics shown in the bottom of Table 5 are very similar to the annual percentiles, indicating again no significant seasonal variation and no substantial difference in the but for
demonstration.

Table 5

. Average, 95th and 99th percentile of PM 10 concentrations ( μ g/m 3 ) in Boise and Nampa

, 2002

– 2011

, in comparison to recorded values during this event

. Statistics are shown for all data (top) and winter season (bottom).

Site Annual

Ave rage Annual 95 th

Percenti le Annual 99 th

Percentile Recorded Values

Feb

. 15 Feb

. 16

Boise 23 45 66 183 156
Nampa 24 56 78 174

Site Seasonal

Ave rage S easonal 9 5 th

Percentile Seasonal 99 th

Percentile Recorded Values

Feb

. 15 Feb

. 16

Boise 20 41 65 183 156
Nampa 19 40 80 174

—



# 8 Mitigation

The mitigation provisions of the EER ( 40 CFR 51.930 ) require that (EPA 2013) :

(a) A State requesting to exclude air quality data due to exceptional events must take appropriate and reasonable actions to protect public health from exceedances or violations of the national ambient air quality standards. At a minimum, the State must:

(1) Provide for prompt public notification whenever air quality concentrations exceed or are expected to exceed an applicable ambient air quality standar d; (2) Provide for public education concerning actions that individuals may take to reduce exposures to unhealthy levels of air quality during and following an exceptional event; and (3) Provide for the implementation of appropriate measures to protect pub lic health from exceedances or violations of ambient air quality standards caused by exceptional events.



### The dust event of February 15 and 16, 2011

, arrived mostly in the evening, without the warning signs that usually accompany high winds such as thunderstorms or very windy conditions. Nevertheless, DEQ’s Boise Regional Office issued a ir quality alerts at 1023 MST on February 15 and again at 0 909 MST on February 16, alerting the public to the high particulate levels and providing public advisory information concerning actions that individuals may take to reduce exposures to unhealthy levels of particulate dust in the air. Given the sudden nature of th e event, and the prompt dispersal of the dust on the morning of February 16

, there was no time nor need
for additional advisories or educational material. DEQ’s public advisory messages and associated public health educational material are provided in Appe ndix E. News stories based on DEQ
advisories that also contributed to informing the public are provided in Appendix F.

In conclusion, the DEQ public notification process successfully alerted the public during this event and in view of the very low frequen cy of occurrence in the prior 10 years, DEQ believesRequest for Concurrence PM 10 Exceptional Events

45 

### that additional public notification measures are not necessary and source mitigation is not
feasible

.



# 9 Procedural Requirements

The EER establishes specific procedural requirements that an air agency must follow to request data exclusion (EPA 2013). Those requirements and DEQ’s actions to meet them are
summarized in Table 6

.

Table 6

. DEQ compli ance with procedural requirements of the e xceptional e vents r ule

. Exceptional Event Rule Procedural Requirements DEQ Action/Intended Action
A State shall notify EPA of its intent to exclude one or more
measured exceedances of an applicable ambient air quality standard as being due to an exceptional event by placing a flag in the appropriate field for the data record of concern which has been submitted to the AQS database ... 40 CFR 50.14(c)(2)(i) DEQ placed flags on the thre e samples described in this report
in prior to July 201 2

.

The placement of the flags and the submittal of an initial event description must be done not later than July 1st of the calendar year following the year in which the flagged measurement occurred. 40 CFR 50.14(c)(2)(iii) DEQ placed flags on the three samples described in this report
in prior to July 201 2

.

A State that has flagged data as being due to an exceptional event and is requesting exclusion of the affected measurement data shall,
after notice and opportunity for public comment, submit a demonstration to justify data exclusion to EPA not later than the lesser of, 3 years following the end of the calendar quarter in which the flagged concentration was recorded or, 12 months prior to the
da te that a regulatory decision must be made by EPA. A State must submit the public comments it received along with its demonstration
to EPA. 40 CFR (50.14(c)(3)(i)) DEQ submitt ed this package for public comment on August 5,
2013. It received no comments in the 30 day public comment period. DEQ is now submit ting it
to EPA for concurrence , less than
3 years following the first quarter of 2011, when the event
occurred.
With the submission of the demonstration, the air agency must document that the public comm ent process was followed . 40 CFR (50.14(c)(3)(iv)) DEQ present ed this
demons tration for public

comment August 5, 2013 for a period of at least 30 days. No public comments were received and no changes were made in the document with the exception
of updates in this table.Request for Concurrence PM 10 Exceptional Events

46 

# 10 References

Adams, K

. D. and D

. W. Sada. 2010. Black Rock Playa, Northwestern Nevada: Physical Processes and Aquatic Life. Desert Research Institute

. Argaman, E., A. Singer, and H. Tsoar. 2006. “Erodibility of Some Crust Forming
Soils/Sediments from the Southern Aral Sea Basin as Determined in a Wind Tunnel.” Earth Surface Process es and Landforms 31:47

- 63.

BLM (United States Bureau of Land Management). 2012. “Burning Man 2012

– 2016 Special
Recreation Permit N VW03500

- 12

- 01 Final Environmental Assessment.” Winnemucca,

NV : BLM , Winnemucca District Office

. DOI

- BLM

- NV

- W030

- 2012

- 0007

- EA

.
DEQ (Idaho Department of Environmental Quality). 2004. Northern Ada County PM 10 

### State Implementation Plan . Boise ID: DEQ.

Draxler , R.R. and G.D. Rolph. 2003. HYSPLIT (HYbrid Single

- Particle Lagrangian Integrated Trajectory) Model Access via NOAA ARL READY Website . N ational O ceanic and

A tmospheric A dministration, Air Resources Laboratory. http://ready.arl.noaa.gov/HYSPLIT_traj.php

EPA (United States Environmental Protection Agency). 2013. Interim Guidance on the Preparation of Demonstrations in Support of Requests to Exclude Ambient Air Quality Data Affected by High Winds Unde r the Exceptional Events Rule . Washington, DC: EPA.

Gillett, S.L., 1997. Toward a Silicate

- based Molecular Nanotechnology. Presented at the Fifth Foresight Conference on Molecular Nanotechnology , November 8. Palo Alto, CA. Accessed October 17, 2012. http://www.foresight.org/Conferences/MNT05/Papers/Gillett1/

Ginoux, P., J.M. Prospero, T.E. Gill, N.C. Hsu, and M. Zhao

. 2012

. “ Global

- S cale A ttribution of

A nthropogenic and N atural D ust S ources and T heir E mission R ates B ased on MODIS Deep Blue A erosol P roducts .” Rev iews of Geophys ics 50

. RG3005,
doi:10.1029/2012RG000388.

Hand J.L. et al. 2011. IMPROVE, Interagency Monitoring of Protected Visual Environments: Spatial and Seasonal Patterns and Temporal Variability of Haze and its Constituents in
the United States

. Fort Collins, CO : Cooperative Institute for Research in the Atmosphere. Colorado State University

. Report V. ISSN 0737

- 5352

- 87

.
Holcombe, T

. L., T

. Ley, a nd D.A. Gillette. 1997 . “ E ffects of P rior P recipitation and S ource A rea C haracteristics on T hreshold W ind V elocities for B lowing D ust E p isodes, Sonoran
Desert 1948

- 78.” Journal of Applied Meteorology 36 : 1160

- 11 75.

Horel, J. et al. 2002

. “ Mesowest: Cooperative Mesonets in the Western United States. ” Bull etin of the Amer ican Meteor logical Soc iety 83 : 211

– 225. http://mesowest.utah.edu/Request for Concurrence PM 10 Exceptional Events

47 

### IMPROVE (Interagency Monitoring of Protected Visual Environments). 2013. “IMPROVE
Aerosol Data. ”. http://vista.cira.colostate.edu/improve/Data/IMPROVE/AsciiData.aspx

Kaplan, M.L., R. Vellore

, and J.M. Lewis

. 2010

. “ Dust S torm O ver the Black Rock Desert, Part

II: Mesoscale S ubgeostrophic J et S treak C irculations O rganizing the D eep C onvective

B oundary L ayer. ” Journal of Geophysical Research

. Submitted.

Lewis, J.M., M.L. Kaplan, R. Vellore, R.M. Rabin, J. Hallett, and S.A. Cohn

. 2011

. “ Dust S torm
O ver the Black Rock Desert: Larger

‐ S cale D ynamic S ignatures .” Journal of Geophysical
Research 116

. D06113, doi:10.1029/2010JD014784.

Marticorena, B., G. Bergametti, D. Gillette, and J. Belnap

. 1997. “ Factors C ontrolling T hreshold

F riction V elocity in S emiarid and A rid A reas of the United States. ” Journal of Geophysical Research 102 : 23, 277

– 23, 287.

M esinger, F. et al . 200 6

. “ North American Regional Reanalysis: A L ong

- T erm, C onsistent,

H igh

- R esolution C limate D ataset for the North American D omain, as a M ajor

I mprovement U pon the E arlier G lobal R eanalysis D atasets in B oth R esolution and

A ccuracy .” Bull etin of the Amer ican Meteor ological Soc iety. 87 , 3, p. 343. March 2006.

National Climatic Data Center

. 2012. “ National Operational Model Archive and Distribution System

, NWS

- NCEP NAM

, 12 km .” Accessed December 6, 2012. http://nomads.ncdc.noaa.gov/data.php?name=access#h ires_weather_datasets

National Weather Service . 2012. “ Hydrometeorological Prediction Center Surface Analysis
Archive.” A ccessed November 23, 2012

. http://www.hpc.ncep.noaa.gov/html/sfc_ar chive.shtml

National Weather Service. 2012. “Upper

- Air Observations Program

- Global Climate Observing System (GCOS).” University of Wyoming Sounding. Assessed November 23, 2012. http://weather.u wyo.edu/upperair/sounding.html

NOAA (National Oceanic and Atmospheric Administration). 2012. “NOAA/ESRL Physical Science Division.” Earth Systems Research Laboratory. Boulder, CO. Accessed November 23, 2012. http://www.esrl.noaa.gov/psd/

NOAA (National Oceanic and Atmospheric Administration). 2013. “ MODIS Satellite I mages .”
A ccessed April 2013

. http://ge.ssec.wisc.edu/modis

- today/

NOAA (National Oceanic and Atmospheric Administration). No date. “Ready HYSPLIT
Model.” http://ready.arl.noaa.gov/HYSPLIT_traj.php

NRC ( National Research Council )

. 1993. Protecting Visibility in National Parks and Wilderness
Areas . Washington, DC: The National Academies Press, 1993.

Pelletier, J.D. 2006. Sensitivity of Playa Windblown

- Dust Emissions to Climactic and Anthropogenic Change.” Journal of Arid Environments 66: 62

- 75.Request for Concurrence PM 10 Exceptional Events

48 

### Reynolds, R.L., J.C. Yount, M. Reheis, H. Goldst ein, P.Chavez, Jr., R. Fulton, J.Whitney,
C. Fuller, and R.M. Forester. 2007. “Dust Emission from Wet and Dry Playas in the Mojave Desert, USA.” Earth Surface Processes Landforms 32:1811

- 1827.

Reynolds, R

. L.

, R. Bogle

, J. Vogel

, H. Goldstein

, and J. Yount

. 2009

. "Dust E mission at Franklin Lake Playa, Mojave Desert (USA)

. Response to M eteorological and H ydrologic
C hanges 2005

- 2008

. " Natural Resources and Environmental Issues 15 ( 18 )

.
Steenburgh, W.J

. , J

. D. Massey

, and T

. H. Painter

. 2012. “ Episodic Dust Even ts of Utah's Wasatch Front and Adjoining Region .” Journal of Applied Meteorology and Climatology
51 : 1654

– 1669.

Tollerud, H

. J. and M

. S. Fantle

. 2012. “ Temporal D evelopment of S urface R oughness and i ts
R elationship with W ater in a P laya D ust S ource: T he I mpact of P recipitation and

I nundation on S urface P roperties .” American Geophysical Union

. Fall Meeting

. Poster
Abstract A33E

- 0208.

Urban, F.E., R.L. Reynolds, and R. Fulton. 2009. The Dynamic Interaction of Climate, Vegetation, and Dust Emission, Mojave Desert, USA.” in Arid Environments and Wind

Erosion . A. Fernandez

- Bernal and M.A. De La Rosa eds. Nova Science Publishers. ISBN
978

- 1

- 60692

- 411

- 2.

USDA (United States Department of Agriculture). 2010. “ Field Crops Usual Planting and Harvesting Dates .” Agricultural Handbook

. Number 628

. National Agricultural Statistics
Service.Request for Concurrence PM 10 Exceptional Events

49Request for Concurrence PM 10 Exceptional Events

50 

# Appendix A. EPA Completion Checklist

Completeness Checklist for High Wind Dust Exceptional Events Demonstration : Site Name/AQS ID: Boise FS 16

- 001

- 0009 POC3 and Nampa FS: 10

- 027

- 0002 POC2
Pollutant: PM10 Date(s): Boise FS: Feb ruary 15 and 16, 2011. Nampa FS: Feb ruary 15, 2011

Table A

- 1. EPA c ompletion c hecklist

. 

### Procedural Criteria EPA Use
Did an exceedance of the NAAQS occur? Yes Were data flagged by July 1 st 

### of following year (or by another appropriate deadline associated with a new or revised NAAQS)? Yes

Was there a 30

- day public comment period?

Is documentation for the comment period included? Aug 2013

Will be
If public comments were received, are the public comments and responses
included? Will
be Was the package submitted within 3 years of the end of the quarter in which the event occurred and 12 months prior to the date that any regulatory decision must be made by the EPA (or by another appropriate deadline associated with a new or revised NAAQS)? Will
be

Evidence Information Included Page(s) E

P
A

U

s

e Conceptual Model p. 1

- 8

- description of weather phenomena resulting in high
wind Yes p. 5 p. 23

- 30

- description of what sources were likely entrained by the high wind Yes p. 1, 3 , 4

- explanation of the path by which the dust reached the monitor(s) Yes p. 5 , 31

- 34

- map showing relevant monitors, topography, other relevant geographic features Yes p. 2

- description of how the event day differs from non

event days Yes p. 38

- 40

- description of concentration and wind patterns for the exceeding monitor(s) and surrounding area Yes p. 5

- 8

Wind Statistics

- max sustained wind (Hourly avg) 35 mph in Nevada p. 7, 8 & App. B

- max sustained wind (1

- 5 min avg) 4 8 mph in Nevada p. 7, 8 & App. B

- max gust (1 min avg) 49 mph in Nevada p. 7, 8 & App. B

- wind trajectories included? Yes p. 32

- 33Request for Concurrence PM 10 Exceptional Events

51 

### - other: Modeled Friction
Velocities p. 26, 27

nRCP

- Area

- specific high wind threshold (default = 25mph) 15

- 22 mph for flat playas p. 3, 4

- sources contributing to event identified, including anthropogenic vs. natural? Yes

- Natural p. 1, 10, 11

- controls identified for anthropogenic sources? (note: level of control analysis depends on wind speed) Not applicable

– no anthropogenic sources N/A

- are natural sources not reasonably controllable? Yes p. 10, 11

- was a High Wind Action Plan included? No

– Not applicable N/A

HF

- were time

- series analyses for concentration and wind
data included? Yes p. 7, 8

- annual comparison to historical data (wind and concentrations) > 99%ile for all 3

con centration values.
83%tile for Boise wind p. 15, 16

- seasonal comparison to historical data (wind and concentrations) > 99%ile for all 3
concentration values.
Local wind no relevant p. 15, 16

CCR (=> AAQ & / Natural Event)

- were spatial analyses included, establishing a spatial relationship between the event, sources, transport of emissions, and recorded concentrations? Yes : a)Satellite Images and b)Hysplit Back

trajectories a)Fig 6,

b)p. 31

- 33

- were temporal analyses included, establishing a temporal relationship between the high wind and
elevated PM concentrations at the monitor? Yes p. 5

- 8 p. 31

- comparison of event

- affected day(s) to specific non

event days? Yes p. 38, 39, 40

- was the dust shown to be from the sources
discussed in the nRCP section? Yes Sec 4 CCR p. 16

- 41

- were alternative hypotheses discussed? Yes p. 40

- 42

- was a causal (not just correlational) relationship
established? Yes Sec 4 CCR p. 16

- 41

NEBF

- was a “but for” analysis included? Yes p. 43

- 44Request for Concurrence PM 10 Exceptional Events

52 

# Appendix B. Supporting Meteorological Data

Table B

- 1. Identification of MESOWEST s tations used in this report (Horel et al. 2002)

.

Station

ID Station Name Mesonet

ID Latitude Longitude Elevation,

ft



### BUFN2 BUFFALO CREEK RAWS 40.5806

- 119.7888 3940

BLUN2 BLUEWING MOUNTAIN RAWS 40.5015

- 119.1216 4570

TR730 DOUBLE H RAWS 41.6525

- 118.0442 6380

JVCI1 JORDAN VALLEY CWMA SCAN 42.9500

- 117.0100 4508

GSFO3 GRASSY MOUNTAIN RAWS 42.6261

- 117.3951 4560

TEXN2 TEXAS SPRINGS RAWS 41.8009

- 118.4514 5760

KBOI BOISE AIR TERMINAL NWS/FAA 43.5670

- 116.2405 2822

KLOL LOVELOCK, DERBY FIELD AIRPT N WS/FAA 40.0684

- 118.5702 3901

KNFL FALLON, NAVAL AIR STATION N WS/FAA 39.43222

- 118.686 3934

KWMC WINNEMUCCA MUNICIPAL AIRPT NWS/FAA 40.9019

- 117.8072 4301



### All meteorologi cal data were obtained from MESOWEST at http://mesowest.utah.edu/

This study was made possible in part due to the data made available by the governmental agencies, commercial firms, and educational institutions participating in MesoWest.

Data quality control information for individual networks a nd additional overall quality control checks implemented by MESOWEST is identified below.

Quality co ntrol for NWS /FAA stations :

Federal Meteorological Handbook No. 1

- Surface Weather Observations and Reports September
2005 : http://www.ofcm.gov/fmh

- 1/fmh1.htm

Quality control for USDA RAWS stations : http://raws.fam.nwcg.gov/nfdrs/WeatherStationStandards.pdf

SCAN

, S oil C limate A nalysis N etwork, Natural Resources Conservation Service, USDA : http://www.wcc.nrcs.usda.gov/scan/

MESOWEST Quality Control : http://mesowest.utah.edu/ html/help/qc.htmlRequest for Concurrence PM 10 Exceptional Events

53 Table B

- 2. Source region w eather s tation d ata from Mesowest (Horel et al. 20 02 )

.

Date/ Time, MST BLUN2

WS mph BLUN2

GUST mph BLUN2

DRCT

° BUFN2

WS mph BUFN2

GUST mph BUFN2

DRCT

° TR730 WS mph TR730 GUST mph TR730

DRCT

° KLOL WS mph KLOL GUST mph KLOL DRCT

°

2/14 02 :00 4 6 302 10 16 221 20 24 185 4.6 180

2/14 03 :00 1 5 118 8 17 202 24 30 193 5.8 110

2/14 04 :00 0 8 244 5 13 244 22 32 191 4.6 340

2/14 05 :00 3 7 281 3 8 290 24 32 197 3.5 120

2/14 06 :00 0 6 305 8 19 215 20 32 194 0

2/14 07 :00 0 5 325 16 30 211 16 25 200 0

2/14 08 :00 2 8 170 12 29 217 20 26 197 0

2/14 09 :00 0 6 33 6 17 277 19 27 201 0

2/14 10 :00 3 7 132 16 26 213 16 25 220 8.1 190

2/14 11 :00 7 16 195 8 22 204 12 22 221 12.7 230

2/14 12 :00 23 35 197 8 21 210 11 18 214 26.5 32.2 220

2/14 13 :00 18 34 200 20 35 225 18 23 215 25.3 38 250

2/14 14 :00 19 32 222 22 41 232 21 38 227 24.2 36.8 250

2/14 15 :00 21 34 233 22 44 230 22 30 226 13.8 21.9 240

2/14 16 :00 22 39 250 21 36 218 25 37 224 16.1 250

2/14 17 :00 19 30 234 18 31 229 26 45 229 25.3 32.2 250

2/14 18 :00 13 31 238 22 29 238 20 33 225 21.9 31.1 260

2/14 19 :00 8 20 243 20 34 230 18 27 219 10.4 260

2/14 20 :00 7 17 239 12 33 232 20 32 207 4.6

2/14 21 :00 6 11 195 7 17 249 27 38 208 12.7 270

2/14 22 :00 8 14 229 5 10 259 20 34 229 6.9 190

2/14 23 :00 8 15 203 3 9 273 20 31 221 4.6 140

2/14 24 :00 4 14 128 5 9 359 21 31 213 0

2/15 01 :00 5 18 184 7 15 213 21 41 209 4.6

2/15 02 :00 13 26 217 5 11 263 22 30 199 4.6 70

2/15 03 :00 18 33 216 7 18 191 24 33 197 4.6 330

2/15 04 :00 27 38 214 2 18 310 29 39 203 8.1 200

2/15 05 :00 27 44 212 5 12 45 32 44 201 0

2/15 06 :00 21 32 211 3 9 206 29 43 200 5.8 300

2/15 07 :00 18 33 205 3 12 300 23 42 195 3.5

2/15 08 :00 9 31 164 2 6 169 26 34 197 4.6 210

2/15 09 :00 11 21 172 4 8 355 31 38 201 3.5 240

2/15 10:00 16 23 183 4 10 184 32 42 200 8.1 250

2/15 11:00 24 34 198 15 28 216 28 41 206 11.5 230

2/15 12:00 23 36 212 16 29 199 28 39 200 10.4 250

2/15 13:00 23 37 199 22 34 220 35 46 203 19.6 26.5 190

2/15 14:00 23 33 204 22 40 222 33 45 211 16.1 24.2 220

2/15 15:00 28 45 216 20 34 212 33 46 225 19.6 27.6 240

2/15 16:00 25 43 210 19 33 215 33 48 223 31.1 36.8 260

2/15 17:00 23 40 214 18 34 215 24 40 233 23 32.2 240

2/15 18:00 25 38 218 12 32 222 22 32 228 25.3 32.2 230

2/15 19:00 17 31 213 18 30 213 18 30 220 24.2 38 230

2/15 20:00 23 37 211 10 26 217 14 23 222 15 240

2/15 21:00 12 35 191 10 32 220 20 30 221 21.9 230

2/15 22:00 12 29 189 8 26 236 16 25 213 18.4 27.6 240

2/15 23:00 11 29 175 5 29 133 19 29 211 9.2 240

2/15 24:00 19 32 189 10 20 155 18 24 205 0

2/16 01 : 00 6 23 217 6 23 165 18 26 188 0

2/16 02 : 00 4 18 137 4 17 156 14 21 168 5.8

2/16 03 : 00 13 23 204 12 31 208 28 36 196 3.5 150

2/16 04 : 00 20 35 211 12 21 216 28 40 194 18.4 240Request for Concurrence PM 10 Exceptional Events

54 Date/ Time, MST BLUN2

WS mph BLUN2

GUST mph BLUN2

DRCT

° BUFN2

WS mph BUFN2

GUST mph BUFN2

DRCT

° TR730 WS mph TR730 GUST mph TR730

DRCT

° KLOL WS mph KLOL GUST mph KLOL DRCT

°

2/16 05 : 00 24 40 218 8 24 201 30 40 194 23 36.8 240

2/16 06 : 00 20 33 207 12 21 204 33 49 205 13.8 230

2/16 07 : 00 16 37 210 17 25 241 29 49 203 16.1 240

2/16 08 : 00 22 35 240 12 35 263 32 43 196 20.7 260

2/16 09 : 00 10 37 242 17 33 268 30 41 229 10.4 270

2/16 10:00 17 29 259 13 29 266 17 43 256 13.8 21.9 290

2/16 11:00 19.6 260

2/16 12:00 21 36 238 7 22 240 12 21 223 23 29.9 270

2/16 13:00 18 32 228 15 23 235 21 27 227 32.2 36.8 270

2/16 14:00 16 27 233 14 23 235 28 37 227 20.7 31.1 260

2/16 15:00 14 26 217 13 32 239 29 39 228 24.2 33.4 280

2/16 16:00 19 28 229 16 28 240 21 43 257 19.6 32.2 260

2/16 17:00 15 30 217 15 26 232 26 37 226 17.3 25.3 250

2/16 18:00 13 29 216 7 29 48 15 30 251 23 29.9 260

2/16 19:00 15 29 212 7 17 170 15 260

2/16 20:00 13 27 212 10 17 203 23 42 222 15 300

2/16 21:00 11 22 210 1 12 192 19 31 214 5.8 200

2/16 22:00 10 21 216 8 14 193 22 34 222 5.8 210

2/16 23:00 2 12 235 2 10 237 27 37 226 8.1 200

2/16 24:00 0 5 160 3 6 352 23 38 226 9.2 210

2/16 01 : 00 3 11 151 3 5 23 14 26 224 8.1 220Request for Concurrence PM 10 Exceptional Events

55 Table B

- 3

. Intermediate (Oregon) and a ffected a rea w eather s tations from MESOWEST (Horel et al. 2002)

.

Date/ Hour MST GSFO3

WS mph GSFO3

GUST mph GSFO3

DRCT ° JVCI1

WS mph JVCI1

GUST mph JVCI1

DRCT ° KBOI

WS mph KBOI

GUST mph KBOI

DRCT °

2/14 02 : 00 16 20 128 6.3 12.3 148 12.7 170

2/14 03 : 00 15 23 133 4.9 9.7 158 13.8 160

2/14 04 : 00 15 20 129 2.7 9.2 166 10.4 170

2/14 05 : 00 17 24 124 1.4 3.8 11 18.4 150

2/14 06 : 00 16 23 124 2 5.5 341 16.1 150

2/14 07 : 00 10 20 134 1.4 4.7 58 15 160

2/14 08 : 00 12 17 137 2.8 7 99 13.8 160

2/14 09 : 00 13 19 147 5.4 11.3 147 4.6 100

2/14 10 : 00 12 19 154 7.3 9.6 142 11.5 160

2/14 11 : 00 13 19 180 4.9 8.1 144 3.5 110

2/14 12 : 00 6 19 218 7 18.6 162 11.5 150

2/14 13 : 00 10 22 207 12.7 18.4 178 16.1 21.9 140

2/14 14 : 00 17 27 206 12.4 18.8 183 19.6 23 130

2/14 15 : 00 27 38 215 17.7 27.7 201 18.4 150

2/14 16 : 00 22 36 209 18.2 28.9 213 12.7 140

2/14 17 : 00 19 33 219 16.9 26.2 220 10.4 140

2/14 18 : 00 18 29 216 13.6 20.4 203 10.4 140

2/14 19 : 00 13 21 191 12.2 19 195 12.7 130

2/14 20 : 00 11 18 193 13 22.1 195 11.5 140

2/14 21 : 00 12 17 185 9.7 17.9 175 10.4 140

2/14 22 : 00 10 15 199 8.5 13.7 159 13.8 130

2/14 23 : 00 16 25 192 8.7 14 168 12.7 140

2/14 24 : 00 26 38 208 8.4 13 163 9.2 130

2/15 01 : 00 14 34 183 11.2 16.2 161 15 130

2/15 02 : 00 14 24 154 8.1 13.8 156 11.5 120

2/15 03 : 00 10 21 134 7.5 11.4 154 16.1 140

2/15 04 : 00 10 19 157 7.7 11.8 155 12.7 120

2/15 05 : 00 8 16 198 10.9 16.6 167 15 130

2/15 06 : 00 0 14 243 5.5 13.7 147 13.8 24.2 120

2/15 07 : 00 10 19 149 6.9 10 147 15 130

2/15 08 : 00 11 19 154 5.5 9.7 150 12.7 120

2/15 09 : 00 13 20 171 8.2 11.5 160 12.7 120

2/15 10:00 14 24 193 7.6 12.2 162 20.7 140

2/15 11:00 23 32 207 9.4 20.8 181 16.1 25.3 150

2/15 12:00 25 38 209 14.6 24.6 193 16.1 140

2/15 13:00 27 41 217 17.1 26.2 199 17.3 23 160

2/15 14:00 28 46 222 18.3 26.5 199 13.8 24.2 140

2/15 15:00 28 48 220 16.8 25 204 12.7 190

2/15 16:00 28 43 217 11.6 20.8 201 13.8 180

2/15 17:00 26 41 210 14.8 24.5 218 18.4 200

2/15 18:00 20 34 219 16.3 27.9 211 12.7 200

2/15 19:00 17 33 219 13.8 23.4 214 4.6 170

2/15 20:00 15 28 218 8.3 14.7 189 5.8 140

2/15 21:00 15 28 193 5.5 8.8 170 0

2/15 22:00 12 23 201 7.1 11.9 171 8.1 160

2/15 23:00 10 17 198 9.5 14.2 166 11.5 150

2/15 24:00 9 17 147 9.5 14 173 12.7 150

2/16 0100 12 25 149 8 13 169 10.4 160

2/16 0200 10 21 147 9.7 14.8 174 15.0 140

2/16 0300 8 18 156 6.2 10.2 161 9.2 130Request for Concurrence PM 10 Exceptional Events

56 Date/ Hour MST GSFO3

WS mph GSFO3

GUST mph GSFO3

DRCT ° JVCI1

WS mph JVCI1

GUST mph JVCI1

DRCT ° KBOI

WS mph KBOI

GUST mph KBOI

DRCT °

2/16 04 :00 11 18 151 6.2 9.9 166 10.4 130

2/16 05 :00 16 23 206 6.2 13 174 11.5 140

2/16 06 :00 14 25 206 8.7 17 181 18.4 140

2/16 07 :00 14 26 202 6.7 15.7 173 5.8 170

2/16 08 :00 17 30 204 8.9 15.7 176 10.4 270

2/16 09 :00 20 27 196 12.5 20.9 188 6.9 40

2/16 10:00 26 37 243 11.9 18.5 179 13.8 280

2/16 11:00 13.3 30.7 205 15.6 23 295

2/16 12:00 7.7 18 321 9.0 303

2/16 13:00 6 14 181 3.5 7.8 250 2.6 355

2/16 14:00 13 21 235 3.3 6.6 163 3.5 200

2/16 15:00 19 27 238 3.1 9 179 4.6 100

2/16 16:00 25 46 258 10.8 22 213 6.9 120

2/16 17:00 17 37 278 15.5 29.1 282 14.7 32.2 258

2/16 18:00 18 29 273 9.1 17.2 282 8.1 70

2/16 19:00 8 26 277 7.3 12.1 286 3.5 90

2/16 20:00 4 12 267 3.4 10.2 316 5.8 120

2/16 21:00 3 11 175 1.6 3.8 82 8.1 60

2/16 22:00 16 24 181 2.8 6.7 147 5.8 110

2/16 23:00 18 28 251 5.7 17.9 153 5.8 120

2/16 24:00 3 20 229 8.6 25.9 175 4.6 170Request for Concurrence PM 10 Exceptional Events

57 Table B

- 4

. Weather o bservations at Lovelock, Boise

, and Winnemucca from Mesowest (Horel et al.
20 02 )

.
Lovelock Nevada, KLOL Boise, ID KBOI Winnemucca, NV KWMC

Date/Time of Obs Weather Obs Date/Time of Obs Weather Obs Date/Time of Obs Weather Obs

2

- 14

- 2011 0:53 PST clear 2

- 14

- 2011 0:53 MST clear 2

- 14

- 2011 0:56 PST clear

2

- 14

- 2011 1:53 PST clear 2

- 14

- 2011 1:53 MST clear 2

- 14

- 2011 1:56 PST clear

2

- 14

- 2011 2:53 PST clear 2

- 14

- 2011 2:53 MST clear 2

- 14

- 2011 2:56 PST clear

2

- 14

- 2011 3:53 PST clear 2

- 14

- 2011 3:53 MST clear 2

- 14

- 2011 3:56 PST clear

2

- 14

- 2011 4:53 PST clear 2

- 14

- 2011 4:53 MST clear 2

- 14

- 2011 4:56 PST clear

2

- 14

- 2011 5:53 PST clear 2

- 14

- 2011 5:53 MST clear 2

- 14

- 2011 5:56 PST clear

2

- 14

- 2011 6:53 PST clear 2

- 14

- 2011 6:53 MST clear 2

- 14

- 2011 6:56 PST clear

2

- 14

- 2011 7:53 PST clear 2

- 14

- 2011 7:53 MST clear 2

- 14

- 2011 7:56 PST clear

2

- 14

- 2011 8:53 PST mostly clear 2

- 14

- 2011 8:53 MST clear 2

- 14

- 2011 8:56 PST clear

2

- 14

- 2011 9:53 PST haze 2

- 14

- 2011 9:53 MST clear 2

- 14

- 2011 9:56 PST overcast

2

- 14

- 2011 9:55 PST haze 2

- 14

- 2011 10:53 MST clear 2

- 14

- 2011 10:56 PST partly cloudy

2

- 14

- 2011 10:03 PST haze 2

- 14

- 2011 11:53 MST clear 2

- 14

- 2011 11:56 PST clear

2

- 14

- 2011 10:12 PST haze 2

- 14

- 2011 12:53 MST clear 2

- 14

- 2011 12:56 PST partly cloudy

2

- 14

- 2011 10:24 PST haze 2

- 14

- 2011 13:53 MST clear 2

- 14

- 2011 13:32 PST haze

2

- 14

- 2011 10:28 PST haze 2

- 14

- 2011 14:53 MST mostly clear 2

- 14

- 2011 13:41 PST haze

2

- 14

- 2011 10:39 PST haze 2

- 14

- 2011 15:53 MST mostly cloudy 2

- 14

- 2011 13:50 PST haze

2

- 14

- 2011 10:51 PST haze 2

- 14

- 2011 16:53 MST mostly cloudy 2

- 14

- 2011 13:56 PST partly cloudy

2

- 14

- 2011 10:53 PST haze 2

- 14

- 2011 17:53 MST overcast 2

- 14

- 2011 14:56 PST haze

2

- 14

- 2011 11:24 PST lt rain 2

- 14

- 2011 18:53 MST overcast 2

- 14

- 2011 15:45 PST partly cloudy

2

- 14

- 2011 11:53 PST lt rain 2

- 14

- 2011 19:53 MST overcast 2

- 14

- 2011 15:56 PST clear

2

- 14

- 2011 12:08 PST lt rain 2

- 14

- 2011 20:53 MST clear 2

- 14

- 2011 16:56 PST haze

2

- 14

- 2011 12:26 PST lt rain 2

- 14

- 2011 21:53 MST mostly clear 2

- 14

- 2011 17:13 PST haze

2

- 14

- 2011 12:33 PST lt rain 2

- 14

- 2011 22:53 MST mostly cloudy 2

- 14

- 2011 17:56 PST partly cloudy

2

- 14

- 2011 12:53 PST haze 2

- 14

- 2011 23:53 MST clear 2

- 14

- 2011 18:56 PST clear

2

- 14

- 2011 13:06 PST haze 2

- 15

- 2011 0:53 MST clear 2

- 14

- 2011 19:56 PST clear

2

- 14

- 2011 13:13 PST haze 2

- 15

- 2011 1:53 MST clear 2

- 14

- 2011 20:56 PST clear

2

- 14

- 2011 13:31 PST haze 2

- 15

- 2011 2:53 MST clear 2

- 14

- 2011 21:56 PST clear

2

- 14

- 2011 13:53 PST haze 2

- 15

- 2011 3:53 MST clear 2

- 14

- 2011 22:56 PST clear

2

- 14

- 2011 14:37 PST haze 2

- 15

- 2011 4:53 MST clear 2

- 14

- 2011 23:56 PST clear

2

- 14

- 2011 14:49 PST haze 2

- 15

- 2011 5:53 MST clear 2

- 15

- 2011 0:56 PST clear

2

- 14

- 2011 14:53 PST haze 2

- 15

- 2011 6:53 MST clear 2

- 15

- 2011 1:56 PST clear

2

- 14

- 2011 15:29 PST haze 2

- 15

- 2011 7:53 MST haze 2

- 15

- 2011 2:56 PST clear

2

- 14

- 2011 15:51 PST haze 2

- 15

- 2011 8:53 MST haze 2

- 15

- 2011 3:56 PST clear

2

- 14

- 2011 15:53 PST haze 2

- 15

- 2011 9:53 MST haze 2

- 15

- 2011 4:56 PST clear

2

- 14

- 2011 16:00 PST haze 2

- 15

- 2011 10:53 MST clear 2

- 15

- 2011 5:56 PST clear

2

- 14

- 2011 16:13 PST haze 2

- 15

- 2011 11:53 MST clear 2

- 15

- 2011 6:56 PST clear

2

- 14

- 2011 16:21 PST haze 2

- 15

- 2011 12:53 MST clear 2

- 15

- 2011 7:56 PST clear

2

- 14

- 2011 16:43 PST haze 2

- 15

- 2011 13:53 MST partly cloudy 2

- 15

- 2011 8:56 PST clear

2

- 14

- 2011 16:45 PST haze 2

- 15

- 2011 14:53 MST mostly clear 2

- 15

- 2011 9:56 PST clear

2

- 14

- 2011 16:53 PST haze 2

- 15

- 2011 15:53 MST clear 2

- 15

- 2011 10:56 PST clear

2

- 14

- 2011 17:01 PST haze 2

- 15

- 2011 16:53 MST mostly clear 2

- 15

- 2011 11:56 PST clear

2

- 14

- 2011 17:03 PST haze 2

- 15

- 2011 17:53 MST mostly clear 2

- 15

- 2011 12:56 PST clear

2

- 14

- 2011 17:53 PST clear 2

- 15

- 2011 18:53 MST mostly cloudy 2

- 15

- 2011 13:56 PST clear

2

- 14

- 2011 18:53 PST clear 2

- 15

- 2011 19:53 MST clear 2

- 15

- 2011 14:56 PST haze

2

- 14

- 2011 19:53 PST clear 2

- 15

- 2011 20:53 MST clear 2

- 15

- 2011 15:56 PST clear

2

- 14

- 2011 20:53 PST haze 2

- 15

- 2011 21:53 MST haze 2

- 15

- 2011 16:32 PST H azeRequest for Concurrence PM 10 Exceptional Events

58 Lovelock Nevada, KLOL Boise, ID KBOI Winnemucca, NV KWMC

Date/Time of Obs Weather Obs Date/Time of Obs Weather Obs Date/Time of Obs Weather Obs

2

- 14

- 2011 21:53 PST clear 2

- 15

- 2011 22:53 MST clear 2

- 15

- 2011 16:41 PST haze

2

- 14

- 2011 22:53 PST clear 2

- 15

- 2011 23:53 MST haze 2

- 15

- 2011 16:51 PST haze

2

- 14

- 2011 23:53 PST clear 2

- 16

- 2011 0:53 MST haze 2

- 15

- 2011 16:56 PST haze

2

- 15

- 2011 0:53 PST clear 2

- 16

- 2011 1:53 MST haze 2

- 15

- 2011 17:03 PST haze

2

- 15

- 2011 1:53 PST clear 2

- 16

- 2011 2:53 MST haze 2

- 15

- 2011 17:15 PST haze

2

- 15

- 2011 2:53 PST clear 2

- 16

- 2011 3:53 MST haze 2

- 15

- 2011 17:56 PST haze

2

- 15

- 2011 3:53 PST clear 2

- 16

- 2011 4:53 MST haze 2

- 15

- 2011 18:15 PST haze

2

- 15

- 2011 4:53 PST clear 2

- 16

- 2011 5:53 MST haze 2

- 15

- 2011 18:45 PST haze

2

- 15

- 2011 5:53 PST clear 2

- 16

- 2011 6:53 MST haze 2

- 15

- 2011 18:56 PST haze

2

- 15

- 2011 6:53 PST clear 2

- 16

- 2011 7:53 MST haze 2

- 15

- 2011 19:56 PST clear

2

- 15

- 2011 7:53 PST clear 2

- 16

- 2011 8:53 MST mostly clear 2

- 15

- 2011 20:19 PST haze

2

- 15

- 2011 8:53 PST clear 2

- 16

- 2011 9:53 MST clear 2

- 15

- 2011 20:34 PST haze

2

- 15

- 2011 9:53 PST clear 2

- 16

- 2011 10:42 MST overcast 2

- 15

- 2011 20:56 PST haze

2

- 15

- 2011 10:31 PST haze 2

- 16

- 2011 10:53 MST overcast 2

- 15

- 2011 21:56 PST haze

2

- 15

- 2011 10:40 PST haze 2

- 16

- 2011 11:16 MST lt snow; fog 2

- 15

- 2011 22:56 PST haze

2

- 15

- 2011 10:44 PST mostly cloudy 2

- 16

- 2011 11:18 MST lt snow; fog 2

- 15

- 2011 23:56 PST clear

2

- 15

- 2011 10:46 PST haze 2

- 16

- 2011 11:26 MST lt snow; fog 2

- 16

- 2011 0:56 PST mostly clear

2

- 15

- 2011 10:53 PST haze 2

- 16

- 2011 11:40 MST lt snow; fog 2

- 16

- 2011 1:56 PST mostly clear

2

- 15

- 2011 11:09 PST haze 2

- 16

- 2011 11:48 MST lt snow; fog 2

- 16

- 2011 2:56 PST mostly cloudy

2

- 15

- 2011 11:22 PST haze 2

- 16

- 2011 11:53 MST lt snow; fog 2

- 16

- 2011 3:56 PST mostly cloudy

2

- 15

- 2011 11:31 PST haze 2

- 16

- 2011 12:06 MST lt snow; fog 2

- 16

- 2011 4:56 PST overcast

2

- 15

- 2011 11:44 PST haze 2

- 16

- 2011 12:14 MST lt snow; fog 2

- 16

- 2011 5:56 PST overcast

2

- 15

- 2011 11:53 PST clear 2

- 16

- 2011 12:51 MST mostly cloudy 2

- 16

- 2011 6:56 PST lt rain

2

- 15

- 2011 12:12 PST haze 2

- 16

- 2011 12:53 MST partly cloudy 2

- 16

- 2011 7:58 PST mod rain

2

- 15

- 2011 12:19 PST haze 2

- 16

- 2011 13:53 MST clear 2

- 16

- 2011 8:01 PST lt snow; fog

2

- 15

- 2011 12:33 PST haze 2

- 16

- 2011 14:53 MST partly cloudy 2

- 16

- 2011 8:10 PST mod snow; fog

2

- 15

- 2011 12:38 PST haze 2

- 16

- 2011 15:53 MST partly cloudy 2

- 16

- 2011 8:31 PST lt snow; fog

2

- 15

- 2011 12:51 PST haze 2

- 16

- 2011 16:03 MST thunder 2

- 16

- 2011 8:36 PST lt snow; fog

2

- 15

- 2011 12:53 PST haze 2

- 16

- 2011 16:12 MST lt snow shwr; squalls 2

- 16

- 2011 8:41 PST lt snow; fog

2

- 15

- 2011 12:57 PST haze 2

- 16

- 2011 16:20 MST mod snow; fog 2

- 16

- 2011 8:56 PST lt snow

2

- 15

- 2011 13:07 PST partly cloudy 2

- 16

- 2011 16:25 MST mostly cloudy 2

- 16

- 2011 9:56 PST overcast

2

- 15

- 2011 13:24 PST haze 2

- 16

- 2011 16:30 MST mostly cloudy 2

- 16

- 2011 10:13 PST lt snow; fog

2

- 15

- 2011 13:39 PST haze 2

- 16

- 2011 16:31 MST mostly cloudy 2

- 16

- 2011 10:23 PST lt snow; fog

2

- 15

- 2011 13:53 PST haze 2

- 16

- 2011 16:34 MST mostly cloudy 2

- 16

- 2011 10:30 PST lt snow; fog

2

- 15

- 2011 14:01 PST haze 2

- 16

- 2011 16:40 MST partly cloudy 2

- 16

- 2011 10:39 PST lt snow; fog

2

- 15

- 2011 14:10 PST haze 2

- 16

- 2011 16:42 MST mostly cloudy 2

- 16

- 2011 10:47 PST lt snow; fog

2

- 15

- 2011 14:41 PST lt rain 2

- 16

- 2011 16:49 MST mostly cloudy 2

- 16

- 2011 10:53 PST lt snow; fog

2

- 15

- 2011 14:53 PST lt rain 2

- 16

- 2011 16:53 MST mostly cloudy 2

- 16

- 2011 10:56 PST lt snow; fog

2

- 15

- 2011 15:12 PST haze 2

- 16

- 2011 17:53 MST clear 2

- 16

- 2011 11:02 PST lt snow

2

- 15

- 2011 15:14 PST haze 2

- 16

- 2011 18:53 MST clear 2

- 16

- 2011 11:10 PST lt snow

2

- 15

- 2011 15:33 PST haze 2

- 16

- 2011 19:53 MST clear 2

- 16

- 2011 11:29 PST mostly cloudy

2

- 15

- 2011 15:42 PST haze 2

- 16

- 2011 20:53 MST clear 2

- 16

- 2011 11:56 PST mostly clear

2

- 15

- 2011 15:53 PST haze 2

- 16

- 2011 21:53 MST clear 2

- 16

- 2011 12:56 PST clear

2

- 15

- 2011 16:06 PST haze 2

- 16

- 2011 22:53 MST mostly cloudy 2

- 16

- 2011 13:56 PST mostly clearRequest for Concurrence PM 10 Exceptional Events

59 Lovelock Nevada, KLOL Boise, ID KBOI Winnemucca, NV KWMC

Date/Time of Obs Weather Obs Date/Time of Obs Weather Obs Date/Time of Obs Weather Obs

2

- 15

- 2011 16:53 PST haze 2

- 16

- 2011 23:53 MST overcast 2

- 16

- 2011 14:56 PST mostly cloudy

2

- 15

- 2011 17:51 PST haze 2

- 16

- 2011 15:56 PST clear

2

- 15

- 2011 17:53 PST haze 2

- 16

- 2011 16:56 PST clear

2

- 15

- 2011 18:09 PST haze 2

- 16

- 2011 17:56 PST clear

2

- 15

- 2011 18:36 PST haze 2

- 16

- 2011 18:56 PST mostly clear

2

- 15

- 2011 18:40 PST haze 2

- 16

- 2011 19:56 PST partly cloudy

2

- 15

- 2011 18:53 PST haze 2

- 16

- 2011 20:56 PST clear

2

- 15

- 2011 19:03 PST haze 2

- 16

- 2011 21:56 PST clear

2

- 15

- 2011 19:06 PST haze 2

- 16

- 2011 22:56 PST partly cloudy

2

- 15

- 2011 19:16 PST haze 2

- 16

- 2011 23:56 PST overcast

Lovelock Nevada, KLOL (cont)

Date & Time of Observation Weather
Obs

2

- 15

- 2011 19:25 PST haze

2

- 15

- 2011 19:42 PST haze

2

- 15

- 2011 19:50 PST haze

2

- 15

- 2011 19:53 PST haze

2

- 15

- 2011 20:36 PST haze

2

- 15

- 2011 20:46 PST haze

2

- 15

- 2011 20:53 PST haze

2

- 15

- 2011 21:02 PST haze

2

- 15

- 2011 21:16 PST haze

2

- 15

- 2011 21:22 PST haze

2

- 15

- 2011 21:29 PST haze

2

- 15

- 2011 21:36 PST haze

2

- 15

- 2011 21:42 PST haze

2

- 15

- 2011 21:53 PST haze

2

- 15

- 2011 21:58 PST haze

2

- 15

- 2011 22:10 PST haze

2

- 15

- 2011 22:16 PST haze

2

- 15

- 2011 22:23 PST haze

2

- 15

- 2011 22:32 PST haze

2

- 15

- 2011 22:47 PST haze

2

- 15

- 2011 22:53 PST haze

2

- 15

- 2011 23:20 PST haze

2

- 15

- 2011 23:36 PST haze

2

- 15

- 2011 23:49 PST haze

2

- 15

- 2011 23:53 PST haze

2

- 16

- 2011 0:10 PST haze

2

- 16

- 2011 0:43 PST haze

2

- 16

- 2011 0:53 PST haze

2

- 16

- 2011 1:00 PST haze

2

- 16

- 2011 1:05 PST haze

2

- 16

- 2011 1:36 PST haze

2

- 16

- 2011 1:43 PST hazeRequest for Concurrence PM 10 Exceptional Events

60 Lovelock Nevada, KLOL Boise, ID KBOI Winnemucca, NV KWMC

Date/Time of Obs Weather Obs Date/Time of Obs Weather Obs Date/Time of Obs Weather Obs

Lovelock Nevada, KLOL (cont)

Date & Time of Observation Weather
Obs

2

- 16

- 2011 1:53 PST haze

2

- 16

- 2011 2:14 PST haze

2

- 16

- 2011 2:22 PST haze

2

- 16

- 2011 2:31 PST haze

2

- 16

- 2011 2:36 PST haze

2

- 16

- 2011 2:53 PST haze

2

- 16

- 2011 3:22 PST haze

2

- 16

- 2011 3:28 PST haze

2

- 16

- 2011 3:35 PST haze

2

- 16

- 2011 3:37 PST haze

2

- 16

- 2011 3:48 PST haze

2

- 16

- 2011 3:49 PST haze

2

- 16

- 2011 4:20 PST haze

2

- 16

- 2011 4:23 PST haze

2

- 16

- 2011 4:51 PST haze

2

- 16

- 2011 4:53 PST haze

2

- 16

- 2011 5:07 PST haze

2

- 16

- 2011 5:14 PST haze

2

- 16

- 2011 5:25 PST haze

2

- 16

- 2011 5:29 PST haze

2

- 16

- 2011 5:31 PST haze

2

- 16

- 2011 5:38 PST mostly cloudy

2

- 16

- 2011 5:53 PST overcast

2

- 16

- 2011 6:16 PST haze

2

- 16

- 2011 6:23 PST haze

2

- 16

- 2011 6:30 PST haze

2

- 16

- 2011 6:53 PST overcast

2

- 16

- 2011 7:20 PST mod rain; fog

2

- 16

- 2011 7:45 PST partly cloudy

2

- 16

- 2011 7:53 PST mostly clear

2

- 16

- 2011 8:53 PST clear

2

- 16

- 2011 9:53 PST clear

2

- 16

- 2011 10:53 PST clear

2

- 16

- 2011 11:53 PST mostly clear

2

- 16

- 2011 12:53 PST clear

2

- 16

- 2011 13:53 PST clear

2

- 16

- 2011 14:53 PST mostly clear

2

- 16

- 2011 15:53 PST mostly clear

2

- 16

- 2011 16:53 PST clear

2

- 16

- 2011 17:53 PST partly cloudy

2

- 16

- 2011 18:53 PST clear

2

- 16

- 2011 19:53 PST clearRequest for Concurrence PM 10 Exceptional Events

61 Lovelock Nevada, KLOL Boise, ID KBOI Winnemucca, NV KWMC

Date/Time of Obs Weather Obs Date/Time of Obs Weather Obs Date/Time of Obs Weather Obs

2

- 16

- 2011 20:53 PST clear

2

- 16

- 2011 21:53 PST clearRequest for Concurrence PM 10 Exceptional Events

62 Table B

- 5

. Daily p recipitation in s ource r egion, January 1

– February 1 5 , 2011 ( Horel et al. 2002 )

.

Date BUFN2 BLUN2 TR730 TEXN2 KNFL KLOL

1/1/2011 0 0 0 0 0.04 0

1/2/2011 0.01 0.02 0.04 0.01 0 0

1/3/2011 0 0 0 0.04 0 0

1/4/2011 0 0 0.01 0 0 0

1/5/2011 0 0 0 0 0 0

1/6/2011 0 0 0 0 0 0

1/7/2011 0 0 0.01 0.05 0 0

1/8/2011 0 0 0 0 0.01 0

1/9/2011 0 0 0 0 0 0

1/10/2011 0 0 0 0 0 0

1/11/2011 0 0 0 0 0 0.08

1/12/2011 0.06 0.04 0 0 0 0

1/13/2011 0.02 0 0 0.16 0 0

1/14/2011 0 0 0.07 0.08 0 0

1/15/2011 0 0 0.13 0.24 0 0

1/16/2011 0 0 0.01 0.09 0 0

1/17/2011 0 0 0 0 0 0

1/18/2011 0 0 0 0 0 0

1/19/2011 0 0 0 0 0 0

1/20/2011 0 0 0 0 0 0

1/21/2011 0 0 0 0 0 0

1/22/2011 0 0 0 0 0 0

1/23/2011 0 0 0 0 0 0

1/24/2011 0 0 0 0 0.01 0

1/25/2011 0 0 0 0 0 0

1/26/2011 0 0 0 0 0 0

1/27/2011 0 0 0 0 0 0

1/28/2011 0 0 0 0 0 0

1/29/2011 0 0 0 0 0 0

1/30/2011 0 0 0 0.03 0.05 0.01

1/31/2011 0 0 0 0 0 0

2/1/2011 0 0 0 0 0 0

2/2/2011 0 0 0 0 0 0

2/3/2011 0 0 0 0 0 0

2/4/2011 0 0 0 0 0 0

2/5/2011 0 0 0 0.07 0 0

2/6/2011 0 0 0 0 0 0

2/7/2011 0 0 0 0 0 0

2/8/2011 0 0 0 0 0 0

2/9/2011 0 0 0 0 0 0

2/10/2011 0 0 0 0 0 0

2/11/2011 0 0 0 0 0 0

2/12/2011 0 0 0 0 0 0

2/13/2011 0 0 0 0 0 0

2/14/2011 0 0 0 0 0 0

2/15/2011 0 0 0 0 0 0Request for Concurrence PM 10 Exceptional Events

63 

# Appendix C. Hells Canyon IMPROVE S ite PM 2.5 

# Speciation

Figure C

- 1. Hells Canyon s peciation for February 2011, showing high coarse mass (top) and elevated soil component on Feb ruary 14,
2011. In top panel, MT = total mass, MF = fine mass, CM = coarse mass. In bottom panel, OCf = fine organic carbon, SO4f = fine sulfate, NO3f = fine nitrate, Opf = fine pyrolysis carbon , Sf = fine sulfur, soilf = fine soil/geologic mass, CHLf = fine chloride, and ECf = fine
elemental carbon ( IMPROVE 2013)

.Request for Concurrence PM 10 Exceptional Events

64 Figure C

- 2. Hells Canyon speciation fo r February 2011 showing higher Si, Fe, Al

, and Ca on Feb ruary 14, 2011. In t o p panel, NAf = fine sodium, SIf = fine silicon, F e f = fine iron, Kf = fine potassium, A l f = fine aluminum, MGf = fine magnesium, CAf = fine c alcium. In bottom panel, Tif = fine titanium, BRf = fine bromine, ZNf = fine zinc, ZRf = fine zirconiuim, PBf = fine lead, and MNf = fine m anganese. Fine
aerosol is < 2.5 μ m ( IMPROVE 2013).Request for Concurrence PM 10 Exceptional Events

65 

# Appendix D. St. Luke ’ s Meridian NCORE Site Speciation Data
for February 14, 2011

Table D

- 1. St. Luke ’ s NCORE s ite s peciation for Feb ruary 14, 2011

— XRF e lements

.

Parameter Code Parameter Sample Value, ug/m3 Alternate

Method
Detectable
Limit Uncertainty Note

88102 Antimony 0 0.042 0.014

88103 Arsenic 0 0.0017 0.00064

88104 Aluminum 0.138 0.013 0.016

88107 Barium 0 0.01 0.0039

88109 Bromine 0.0023 0.0018 0.0011

88110 Cadmium 0 0.019 0.0062

88111 Calcium 0.147 0.0047 0.011

88112 Chromium 0 0.0022 0.00072

88113 Cobalt 0.00081 0.0011 0.00071

88114 Copper 0.00023 0.0013 0.0017

88115 Chlorine 0.0409 0.005 0.0037

88117 Cerium 0 0.0068 0.003

88118 Cesium 0 0.034 0.011

88126 Iron 0.147 0.0014 0.011

88128 Lead 0 0.0049 0.0016

88131 Indium 0 0.022 0.0073

88132 Manganese 0.00306 0.0018 0.0008

88136 Nickel 0.00001 0.0011 0.00045

88140 Magnesium 0.00671 0.011 0.0044

88152 Phosphorus 0 0.01 0.0041

88154 Selenium 0 0.002 0.00068

88160 Tin 0 0.032 0.011

88161 Titanium 0.0113 0.0043 0.0026

88164 Vanadium 0 0.003 0.0013

88165 Silicon 0.554 0.011 0.046

88166 Silver 0 0.015 0.0049

88167 Zinc 0 0.0035 0.0012

88168 Strontium 0 0.0023 0.00076

88169 Sulfur 0.105 0.0073 0.0082 a

88176 Rubidium 0 0.0018 0.00059

88180 Potassium 0.0803 0.0039 0.006

88184 Sodium 0.0961 0.04 0.014

88185 Zirconium 0 0.0045 0.0069

88301 Ammonium 0.147 0.017 0.01

88302 Sodium 0.0351 0.03 0.064Request for Concurrence PM 10 Exceptional Events

66 Parameter Code Parameter Sample Value, ug/m3 Alternate

Method
Detectable
Limit Uncertainty Note

88303 Potassium 0 0.014 0.001

88306 Nitrate 0.27 0.0072 0.021

88403 Sulfate 0.232 0.01 0.019 b

88502 Particulate matter

2.5u 6.1 0.77 0.41

88355 OC IMPROVE TOT 0.989 c

88357 EC IMPROVE TOT 0.244 d

88370 OC IMPROVE

TOR 0.975 e

88374 O1 IMPROVE 0.0241

88375 O2 IMPROVE 0.204

88376 O3 IMPROVE 0.368

88377 O4 IMPROVE 0.218

88378 OP IMPROVE

TOR 0.161 f

88380 EC IMPROVE TOR 0.258 g

88383 E1 IMPROVE 0.373

88384 E2 IMPROVE 0.0458

88385 E3 IMPROVE 0

88388 OP IMPROVE TOT 0.175 h

Notes :

a Qualifier

- 1 = 5

b Qualifier

- 1 = 5

c OC = Organic Carbon, TOT = by total optical TRANSMITTANCE

d EC = Elemental Carbon, TOT = by total optical TRANSMITTANCE

e OC = Organic Carbon, TOR = by total optical REFLECTANCE

f OP = Pyrolysis Carbon, TOR = by total optical REFLECTANCE

g EC = Elemental Carbon, TOR = by total optical REFLECTANCE

h OP = Pyrolysis Carbon, TOR = by total TRANSMITTANCERequest for Concurrence PM 10 Exceptional Events

67 

# Appendix E. DEQ Air Quality Alerts and Public Education

Air q uality a lert and p ublic e ducation sheet for y ellow a lerts sent out February 15, 2011

, 10:23 a

. m

. MST by DEQ’s Boise Regional Office.Request for Concurrence PM 10 Exceptional Events

68Request for Concurrence PM 10 Exceptional Events

69 

### Air q uality a lert and p ublic e ducation sheet for o range a lerts sent out February 16, 2011

, 9:09 a

. m

. MST by DEQ’s Boise Regional Office.Request for Concurrence PM 10 Exceptional Events

70Request for Concurrence PM 10 Exceptional Events

71 

# Appendix F. News Article s

Idaho Statesman, The (Boise, ID) February 16, 2011 Section: Local, as provided by the The McClatchy Company

Wind

- blown dust leads to orange air quality alert in Treasure Valley, but snow expected to improve air quality

Author: Boise

- Idaho Statesman

Article Text:

The Idaho Department of Environmental Quality issued an orange alert for Wednesday due to poor air quality. The cause is particulates from dust that has blown in from the desert, said David Luft, airshed coordinator for the Boise regional office.

An orange alert means that members of sensitive groups should limit time outdoors. Indoor wood burning is restricted in Ada County when the AQI is 74 or higher. Within unincorporated Ada and Canyon counties, only EPA

- certified woodstoves are allowed when A QI is above 74.

"This is pretty high for us," Luft said of the air quality index of 110, the low end of the orange level.

Luft said dry conditions combined with sustained winds of 10 to 20 miles per hour from the southeast for two days impacted air quali ty.

Luft expected that precipitation overnight Tuesday would prevent the need for an alert, but that did not materialize and the air quality got worse. The cold front moving through the area Wednesday should clear the air, Luft said.

Snow was falling thr oughout the Boise metro area Wednesday morning. The Valley will get a half inch to 1 inch of snow today, according to meteorologist Megan Thimmesch. She said Boise hit a high temperature for the day of 46, and temperatures will fall through the rest of the day.

It was about 34 degrees at noon, and the overnight low is expected to be about 30 degrees. There's a 25 percent chance of precipitation Thursday, and that's likely to be snow. The high Thursday will be about
41.

Copyright (c) 2011 The Idaho Statesm an, All Rights Reserved. Record Number: 201102161456KNRIDDERIDSTATES_6f947997a02ef64f079c76f03f11475aRequest for Concurrence PM 10 Exceptional Events

72 

### NBC

- 7 KTVB (Boise, ID) February 16, 2011
Section: Local News

Treasure Valley air quality improves, in moderate range

Article Text:

BOISE

-- The Idaho Department of Environmental Quality reports that air quality in the Treasure Valley has improved and is now in the moderate or yellow range.

As of 2 p.m. Mountain Time, DEQ's website puts the Air Quality Index at 65.

Idaho's Chief Mete orologist Rick Lantz credits the precipitation we received earlier in the day for the improved air quality. He says there was a lot of dust in the air before the storm moved through.

High winds overnight were responsible for an orange air quality alert in the Treasure Valley. The AQI hit
110.

An orange air quality alert means the air quality is unhealthy for sensitive groups, meaning people with respiratory or heart disease, the elderly, and children.

While the alert is in effect, outdoor burning is proh ibited.

Even though the air quality is back in the moderate range, usually sensitive people are encouraged to
reduce their outdoor activities.

© 2011 King Broadcasting Company, a subsidiary of Belo Corp. All Rights