MPERIAL COUNTY AIR POLLUTION CONTROL DISTRICT

Transcription

1 MPERIAL COUNTY AIR POLLUTION CONTROL DISTRICT PHOTO COURTESY OF NASA NASA LANDSAT-5 (LDCM) satellite picture April 15, 2013 and April 16, 2013 Exceptional Event Documentation For the Imperial County PM 10 Nonattainment Area DRAFT REPORT February 26, 2015

2 TABLE OF CONTENTS SECTION PAGE I Introduction...1 I.1 Demonstration Contents...1 I.2 Requirements of the Exceptional Event Rule...2 I.2.a Public Notification that a potential event was occurring...2 I.2.b Notification to USEPA of the intent to exclude a measured violation (40 CFR (c)(2)(i))...2 I.2.c Documentation that the public comment process was followed for the event demonstration that was flagged for exclusion (40 CFR (c)(3)(v))...3 I.2.d Documentation submittal supporting an Exceptional Event Flag (40 CFR (a)(1-2))...3 I.2.e Necessary demonstration to justify an exclusion of data under (40 CFR (c)(3)(iv))...3 II July 2, 2013 Conceptual Model...5 II.1 Geographic Setting and Monitor Locations...5 II.2 Climate...9 II.3 Event Day Summary...13 III Historical Norm...18 III.1 Analysis...18 III.2 Summary...23 IV Not Reasonably Controllable or Preventable...24 IV.1 Background...24 IV.1.a Control Measures...25 IV.1.b Additional Measures...26 IV.1.c Review of Source-Permitted Inspections and Public Complaints...27 IV.2 Forecasts and Warnings...27 IV.3 Wind Observations...27 IV.4 Summary...28 V Clear Causal Relationship...29 V.1 Discussion...29 V.2 Summary...36 VI But-For-Analysis...37 VI.1 Discussion...37 VI.2 Summary...38

3 VII Conclusions...40 VII.1 Affects Air Quality...40 VII.2 Not Reasonably Controllable or Preventable...40 VII.3 Natural Event...41 VII.4 Clear Causal Relationship...41 VII.5 Historical Norm...41 VII.6 But For...41 Appendix A: Public Notification that a potential event was occurring (40 CFR 50.14(c)(1)(i))...44 Appendix B: Meteorological Data...48 Appendix C: Correlated PM 10 Concentrations and Winds...56 Appendix D: Regulation VIII Fugitive Dust Rules...62

4 LIST OF FIGURES FIGURE PAGE Figure 2-1: Colorado Desert Area Imperial County...5 Figure 2-2: Surrounding Areas of the Salton Sea...6 Figure 2-3: Location and Topography of Imperial County...7 Figure 2-4: Deserts in California, Yuma and Mexico...7 Figure 2-5: Monitoring Sites in Imperial County...8 Figure 2-6: Sonoran Desert Region...10 Figure 2-7: Imperial County Historical Weather...11 Figure 2-8: Weather Pattern of the North American Monsoon...12 Figure 2-9: Prevailing and Dominant Wind Direction Morning of July 2, Figure 2-10: Time Sequence Analysis July 2, Figure 2-11: NOAA HYSPLIT Model...16 Figure 2-12: NOAA HYSPLIT Model in a Geographical Base Map...17 Figure 2-13: 72 Hour PM 10 Concentrations at Various Stations on July 2, Figure 3-1 Figure 3-2 Figure 3-3 Figure 3-4 Figure 3-5 Brawley Historic FRM and FEM PM Hr Avg Concentrations January 1, 2010 to July 2, Niland Historic FRM and FEM PM Hr Avg Concentrations January 1, 2010 to July 2, Brawley and Niland Historic FRM and FEM PM Hr Avg Concentrations January 1, 2010 to July 2, Brawley Seasonal Comparison PM Hr Avg Concentrations June 1, 2010 to August 31, Niland Seasonal Comparison PM Hr Avg Concentrations

5 June 1, 2010 to August 31, Figure 3-6 Figure 3-7 Figure 3-8 Figure 4-1 Brawley and Niland Seasonal Comparison PM Hr Avg Concentrations June 1, 2010 to August 31, Brawley and Niland Historical PM Hr FRM & FEM Concentrations Jan 2010 to July 2, Brawley and Niland Seasonal PM Hr FRM & FEM Concentrations June 1, 2010 to August 31, Regulation VIII Graphic Timeline Development...25 Figure 5-1 Storm System with Winds Moving into Imperial County...29 Figure Hour Wind Comparison of Neighboring Sites...30 Figure 5-3 Brawley Correlation of PM 10 Concentrations & Wind Speeds...31 Figure 5-4 Niland Correlation of PM 10 Concentrations & Wind Speed...32 Figure 5-5 Brawley and Niland Correlation of PM 10 Concentrations & Wind Speed...32 Figure 5-6 Figure Hour Time Series PM 10 Concentrations & Wind Speeds Imperial Airport (KIPL) Hour Time Series PM 10 Concentrations & Visibility Imperial Airport (KIPL)...34 Figure 5-8 Time Sequence Analysis of July 2, Figure 5-9 Imperial Valley Air Quality Index in Brawley July 2, Figure 6-1 Brawley-Niland 3-Day 24-Hr PM 10 Concentrations July 1 thru July 2,

6 LIST OF TABLES TABLE Table 1-1 Table 2-1 PAGE Brawley and Niland Concentrations of PM 10 on July 2, Monitoring Sites in Imperial County, Riverside County and Arizona July 2, Table 2-2 Wind Speeds on July 2, Table 6-1 Imperial County Comparison to Normals...40 Table 7-1 Technical Elements Checklist...41

7 ACRONYM DESCRIPTIONS AQI Air Quality Index AQS Air Quality System BACM Best Available Control Measures BAM 1020 Beta Attenuation Monitor Model 1020 BLM United States Bureau of Land Management BP United States Border Patrol CAA Clean Air Act CARB California Air Resources Board CMP Conservation Management Practice DCP Dust Control Plan DPR California Department of Parks and Recreation EER Exceptional Events Rule FEM Federal Equivalent Method FRM Federal Reference Method HF Historical Fluctuations HYSPLIT Hybrid Single Particle Lagrangian Integrated Trajectory Model ICAPCD Imperial County Air Pollution Control District ITCZ Inter Tropical Convergence Zone KIPL Imperial County Airport MPH Miles Per Hour MST Mountain Standard Time MXL Mexicali Airport NAAQS National Ambient Air Quality Standard NCAR National Center for Atmospheric Research NEAP Natural Events Action Plan NEXRAD Next-Generation Radar NOAA National Oceanic and Atmospheric Administration nrcp Not Reasonably Controllable or Preventable NWS National Weather Service PM 10 Particulate Matter less than 10 microns PM 2.5 Particulate Matter less than 2.5 microns PSP Palm Springs Airport PST Pacific Standard Time QA/QC Quality Assured and Quality Controlled RACM Reasonable Available Control Measure SIP State Implementation Plan SLAMS State Local Ambient Air Monitoring Station SMP Smoke Management Plan SSI Size-Selective Inlet USEPA United States Environmental Protection Agency USGS United States Geological Survey UTC Coordinated Universal Time ( WRCC Western Regional Climate Center

8 I Introduction On two consecutive days April 15, 2013 and April 16, 2013, the State and Local Ambient Air Monitoring Stations (SLAMS) (AQS Site Codes and ), located in Brawley and Niland, California recorded violations of the National Ambient Air Quality Standard (NAAQS) when both the Federal Referenced Method (FRM) Size-Selective Inlet (SSI) high volume sampler and the Federal Equivalent Method (FEM), Beta Attenuation Monitor Model 1020 (BAM 1020) measured violations of the NAAQS. On April 15, 2013 while no FRM violations occurred, both the Brawley and Niland FEM BAM 1020 monitors measured (midnight to midnight) 24-hour (hr) average Particulate Matter less than 10 microns (PM 10 ) concentrations of µg/m 3 and µg/m 3, respectively. Similarly, on April 16, 2013 the Brawley monitor measured an FRM (midnight to midnight) 24-hr average concentration of 165 µg/m 3 and an FEM BAM 1020 measurement (midnight to midnight) 24-hr average concentration of µg/m 3. PM hr measurements recorded above the 150 µg/m 3 are violations of the NAAQS. April 15, 2013 was not a scheduled run day for the FRM Size-Selective Inlet (SSI) high volume samplers in Imperial County. The SLAMS in Brawley and Niland were the only stations, in Imperial County to record violations of the PM 10 NAAQS on April 15, 2013 and April 16, 2013 TABLE 1-1 BRAWLEY AND NILAND CONCENTRATIONS OF PM 10 ON APRIL 15 AND APRIL 16 DATE MONITORING SITE AQS ID POC(s) HOURS 24-HOUR CONCENTRATION ug/m 3 PM 10 NAAQS ug/m 3 04/15/2013 Niland /15/2013 Brawley /16/2013 Brawley /16/2013 Brawley The Imperial County Air Pollution Control District (ICAPCD) has been submitting PM 10 data from FRM SSI instruments since 1986 into the United States Environmental Protection Agency's (USEPA) Air Quality System (AQS). Most recently, since 2013 ICAPCD has been submitting continuous PM 10 data from BAM 1020's. On both April 15, 2013 and April 16, 2013 the Brawley and Niland monitors were impacted by elevated particulate matter caused by the entrainment of fugitive windblown dust generated by a large upper-level low over the Pacific Northwest which swung through the Great Basin the evening of the 14 th through the 16 th driving strong and gusty westerly winds into Imperial County. This report demonstrates that the violations observed on April 15, 2013 and April 16, 2013 were caused by a naturally occurring event which elevated particulate matter affecting air quality, was not reasonably controllable or preventable (nrcp), was in excess of normal historical fluctuations (HF) and would not have occurred "but for" the entrainment of fugitive windblown dust from outlaying deserts and mountains from the Sonoran Desert. The document further substantiates the request by the ICAPCD to flag PM hour NAAQS

9 violations of 248.4µg/m 3, 305.3µg/m 3, 189.4µg/m 3 and a violation of 165µg/m 3 as exceptional events. This demonstration substantiates that the two day event meets the definition of the USEPA Regulation for the Treatment of Data Influenced by Exceptional Events (EER) 1. I.1 Demonstration Contents Section II - Describes the April 15 th and April 16, 2013 event as it occurred in Imperial County, providing background information of the exceptional event and explaining how the event affected air quality. Overall, this section provides the evidence that the event was a natural event. Section III Describes the normal historical fluctuations using data charts, summaries, and time-series graphs which demonstrate that the elevated concentrations of PM 10 on April 15 th and April 16, 2013 were in excess of normal historical fluctuations. Section IV - Provides evidence that the event of April 15 th and April 16, 2013 was not reasonably controllable or preventable despite the full enforcement and implementation of Best Available Control Measures (BACM). Section V - Discusses and establishes the clear causal relationship between the violation at the Brawley and Niland stations and the natural event which occurred on April 15 th and April 16, This section provides evidence that the event affected air quality as a result of a natural event. Section VI - Brings together the evidence presented within this report and shows a clear causal relationship between the natural event, the violation and how BACM is overwhelmed making it nrcp concluding that the violation which occurred April 15 th and April 16, 2013 would not have occurred "but for" the natural event. I.2 Requirement of the Exceptional Event Rule The above sections combined comprise the technical requirements described under the Exceptional Events Rule (EER) under 40 CFR 50.14(c)(3)(iv). However, there are additional non-technical requirements that must be met in order for the USEPA to concur with flagged air quality monitoring data. I.2.a Public Notification that a potential event was occurring The ICAPCD provided notification, on April 15 th and April 16, 2013, via the ICAPCD s webpage that winds could potentially gust in excess of 35 miles per hour (mph) potentially elevating particulate matter. Because of the potential for suspended particles and poor air quality, the ICAPCD issued a "No Burn" day in Imperial County. Appendix A contains copies of notices as 1 "Treatment of Data Influenced by Exceptional Events; Final Rule", 72 FR 13560, March 22, 2007

10 they were issued during the morning of April 15 th and April 16, I.2.b Notification to USEPA of the intent to exclude a measured violation (40 CFR 50.14(c)(2)(I)) States are required under federal regulation to submit measured ambient air quality data into the AQS. AQS is the federal repository of Quality Assured and Quality Controlled (QA/QC) air ambient data used for regulatory purposes. Ambient data that is potentially influenced by an exceptional event must be appropriately flagged and initially described and submitted to USEPA according to 40 CFR 50.14(c)(2)(iii) no later than July 1 st of the calendar year following the year in which the flagged measurement occurred. The ICAPCD made two separate written requests to the California Air Resources Board (CARB) to place preliminary flags on SLAMS measured concentrations in Brawley and Niland. The first request dated March 17, 2014 requested an initial flag for the measurement from the PM 10 SSI Hi Volume Gravimeter sampler in Brawley of 165 µg/m 3. The second request, dated May 14, 2014 requested an initial flag for the measurements from the BAM 1020 monitors in Brawley and Niland of 248.4µg/m 3, 189.4µg/m 3, and 305.3µg/m 3. A brief description was included with the initial flag of the meteorological data which indicated a potential natural event had occurred on April 15 th and April 16, I.2.c Documentation that the public comment process was followed for the event demonstration that was flagged for exclusion (40 CFR 50.14(c)(3)(v)) The ICAPCD posted, for a 30 day public review, a draft version of this demonstration on the ICAPCD webpage and published a notice of availability in the Imperial Valley Press on XX XX, The notice advised the general public that comments were being solicited regarding this demonstration which supports the request, by the ICAPCD, to exclude the measured concentrations of 248.4µg/m 3, 189.4µg/m 3 and 165µg/m 3 for Brawley and 305.3µg/m 3 for Niland which occurred on April 15 th and April 16, The final closing date for comments was XX XX, Appendix A contains a copy of the public notice affidavit along with any comments received by the ICAPCD for submittal as part of the demonstration (40 CFR 50.14(c)(3)(i)). I.2.d Documentation submittal supporting an Exceptional Event Flag (40 CFR 50.14(a)(1-2)) States that have flagged data as a result of an exceptional event and who have requested an exclusion of said flagged data are required to submit a demonstration that justifies the data exclusion to the USEPA no later than 3 years following the end of the calendar quarter in which the flagged concentration was measured or 12 months prior to the date that a regulatory decision must be made by USEPA. The ICAPCD, after the close of the comment period and after consideration of the comments will submit this demonstration along with all required elements, including received comments

11 and responses to USEPA Region 9 in San Francisco, California. The deadline for the submittal of this demonstration is June 30, I.2.e Necessary demonstration to justify an exclusion of data under (40 CFR 50.14(c)(3)(iv)) A This demonstration provides evidence that the event, as it occurred on April 15 th and April 16, 2013, satisfies the definition in 40 CFR 50.1(j) and (k) for an exceptional event. a The event affects air quality b The event is not reasonably controllable or preventable. c The event is caused by human activity that is unlikely to recur at a particular location or [is] a natural event. d The event is a natural event where human activity played little or no direct casual role. B C D This demonstration provides evidence that air quality was affected by the exceptional event in Imperial County. There is a clear causal relationship between the event and the measured concentrations in Brawley and Niland supporting that the event affected the air quality in Imperial County. This demonstration provides evidence that the measured concentration, caused by the event, is in excess of normal historical fluctuations. This demonstration provides evidence that but-for the event there would have been no exceedance (violation). II April 15, 2013 and April 16, 2013 Conceptual Model This section provides a summary description of the meteorological and air quality conditions under which the April 15 th and April 16, 2013 event unfolded in Imperial County. The subsection elements include» A description and map of the geographic setting of the air quality and meteorological monitors» A description of Imperial County s climate» An overall description of meteorological and air quality conditions on the event day. II.1 Geographic Setting and Monitor Locations According to the United States Census Bureau, Imperial County has a total area of 4,482 square miles of which 4,177 square miles is land and 305 square miles is water. Much of Imperial County is below sea level and is part of the Colorado Desert an extension of the larger Sonoran Desert (Figure 2-1).

12 FIGURE 2-1 COLORADO DESERT AREA IMPERIAL COUNTY Fig 2-1: 1997 California Environmental Resources Evaluation System. According to the United States Geological Survey (USGS) Western Ecological Research Center the Colorado Desert bioregion is part of the bigger Sonoran Desert Bioregion which includes the Colorado Desert and Upper Sonoran Desert sections of California and Arizona, and a portion of the Chihuahuan Basin and Range Section in Arizona and New Mexico (Forest Service 1994). A notable feature in Imperial County is the Salton Sea which is at 235 feet below sea level. The Chocolate Mountains are located east of the Salton Sea and extend in a northwest-southeast direction for approximately 60 miles (Figure 2-2). In this region, the geology is dominated by the transition of the tectonic plate boundary from rift to fault. The southernmost strands of the San Andreas Fault connect the northern-most extensions of the East Pacific rise. Consequently, the region is subject to earthquakes and the crust is being stretched, resulting in a sinking of the terrain over time. FIGURE 2-2

13 SURROUNDING AREAS OF THE SALTON SEA Fig 2-2: Image courtesy of the Image Science and Analysis Laboratory NASA Johnson Space Center, Houston Texas All of the seven incorporated cities are surrounded by agricultural fields to the north, east, west and south (Figure 2-3). Together, the incorporated cities and agricultural fields make what is known as the Imperial Valley. Surrounding the Imperial Valley are desert areas found on the eastern and western portions of Imperial County. FIGURE 2-3 LOCATION AND TOPOGRAPHY OF IMPERIAL COUNTY Niland Westmorland Calipatria Brawley El Centro Imperial Calexico Holtville Mexicali, Mexico Fig 2-3: Depicts the seven incorporated cities within Imperial Valley - City of Calipatria, City of Westmorland, City of Brawley, City of Imperial, City of El Centro, City of Holtville, City of Calexico. At the south is Mexicali Mexico.

14 Furthermore, the deserts located to the east and west of Imperial County expand to the southeast, and southwest into Mexico (Sonoran Desert) (Figure 2-4). Combined, these deserts are sources of dust emissions which impact the Imperial County during high wind events. FIGURE 2-4 DESERTS IN CALIFORNIA, YUMA AND MEXICO Fig 2-4: Depicts the Sonoran Desert as it extends from Mexico into Imperial County. The air quality and meteorological monitoring stations used in this demonstration are shown in Figure 2-5. SLAMS in Imperial County are located in Calexico, El Centro, Westmorland, and Niland. Each station measures air quality and meteorological data; the station located in Brawley only measures air quality and no meteorological data. Other air monitoring stations with air quality and meteorological data used for this demonstration include station in Riverside County and Arizona (Figure 2-5 and Table 2-1). As mentioned above, the PM 10 violation on April 15 th and April 16, 2013, occurred at the Brawley and Niland stations. The Brawley and Niland stations, which are located east of Westmorland but North of El Centro, are regarded as the northern most area monitoring sites within the Imperial County air monitoring network. In order to properly analyze the contributions of meteorological conditions occurring on April 15 th and April 16, 2013, other meteorological sites used in this demonstration include the Palm Springs Airport (PSP), the Naval Air Facility (NJK), Imperial County Airport (KIPL), and when available the Mexicali Airport (MXL) (Figure 2-5). FIGURE 2-5 MONITORING SITES IN IMPERIAL COUNTY

15 Fig 2-5: Depicts a select group of meteorological and PM 10 monitoring sites in Imperial County, eastern Riverside County and Mexicali. The image exemplifies the regional area as it existed on April 15, 2013 and April 16, Monitor Site Name TABLE 2-1 MONITORING SITES IN IMPERIAL COUNTY, RIVERSIDE COUNTY AND ARIZONA APRIL 15, 2013 AND APRIL 16, 2013 Operator* Monitor Type AQS ID AQS PARAMETER CODE ARB Site Number Elevation (meters) Day 24-hr PM 10 (ug/m 3 ) Avg 1-hr PM 10 (ug/m 3 ) Max Time of Max Reading (PDT) Max Wind Gust (mph) Time of Max Wind Gust IMPERIAL COUNTY El Centro-9th Street ICAPCD Hi-Vol Gravimetric (81102) th :00 16th :00 Brawley-Main Street #2 ICAPCD BAM th : :53 BAM (81102) th : : Hi-Vol 16th :53 Gravimetric Westmorland ICAPCD Hi-Vol Gravimetric (81102) th :53 16th :53 Niland- English Road ICAPCD BAM th : :00 BAM (81102) th : : Hi-Vol 16th :00 Gravimetric

16 Bombay Beach Naval Test Base IID TEOM N/A PM10_LHR IID TEOM N/A PM10_LHR th : :00 16th :00 15th : th Salton City IID TEOM N/A PM10_LHR Sonny Bono IID TEOM N/A PM10_LHR th : th : th : :00 16th :00 RIVERSIDE COUNTY Palm Springs Fire Station SCAQMD TEOM (81102) th : :53 16th : :53 Indio (Jackson St.) SCAQMD TEOM (81102) th :53 16th :53 RIVERSIDE COUNTY - INDIAN TRIBAL LAND Torres - Martinez TM TEOM (81102) th : :00 16th : :00 ARIZONA YUMA Yuma Supersite ADEQ TEOM (81102) N/A 15th : :55 16th : :55 CARB = California Air Resources Board IID = Imperial Irrigation District APCD = Air Pollution Control District, Imperial County SCAQMD = South Coast Air Management Quality District TM = Torres-Martinez Tribal Environmental Department ADEQ =Arizona Department of Environmental Quality LHR=Local Hourly II.2 Climate As mentioned above, Imperial County is part of the Colorado Desert, which is a subdivision of the larger Sonoran Desert (Figure 2-6) encompassing approximately 7 million acres (28,000 km 2 ). The desert area encompasses Imperial County and includes parts of San Diego County, Riverside County, and a small part of San Bernardino County. FIGURE 2-6

17 SONORAN DESERT REGION Fig 2-6: Depicts the magnitude of the region known as the Sonoran Desert The majority of the Colorado Desert lies at a relatively low elevation, below 1,000 feet (300 m), with the lowest point of the desert floor at 275 feet (84 m) below sea level at the Salton Sea. Although the highest peaks of the Peninsular Range reach elevations of nearly 10,000 feet (3,000 m), most of the region's mountains do not exceed 3,000 feet (910 m). In the Colorado Desert (Imperial County), the geology is dominated by the transition of the tectonic plate boundary from rift to fault. The southernmost strands of the San Andreas Fault connect to the northern-most extensions of the East Pacific Rise. Consequently, the region is subject to earthquakes, and the crust is being stretched, resulting in a sinking of the terrain over time. The Colorado Desert's climate distinguishes it from other deserts. The region experiences greater summer daytime temperatures than higher-elevation deserts and almost never experiences frost. In addition, the Colorado Desert experiences two rainy seasons per year (in the winter and late summer), especially toward the southern portion of the region; the more northerly Mojave Desert usually has only winter rains. The west coast Peninsular Ranges, or other west ranges, of Southern California northern Baja California, block most eastern Pacific coastal air and rains, producing an arid climate. Other short or longer-term weather events can move in from the Gulf of California to the south, and

18 are often active in the summer monsoons. These include remnants of Pacific hurricanes, storms from the southern tropical jet stream, and the northern Inter Tropical Convergence Zone (ITCZ). The arid nature of the region is demonstrated when historic annual average precipitation levels in Imperial County average 3.11 (Figure 2-7). During the 12 month period prior to April 15 th and April 16, 2013 Imperial County recorded total annual precipitation of 1.86 inches. FIGURE 2-7 IMPERIAL VALLEY HISTORICAL WEATHER Temperature *F Precipitation (inches) Precipitation Avg Max Temp Avg Min Temp Fig 2-7: Historic Imperial Valley weather. Prior to April 15 th and April 16, 2013, the region experienced dramatically lower than normal precipitation. The total annual precipitation from May 2012 through April 2013 was 1.86" a much lower level than the historical annual average of 3.11". Source: California Observed Climate Normals and Weather Underground. While windblown dust events in Imperial County during the summer monsoon season are often due to outflow winds from thunderstorms, windblown dust events in the fall, winter, and spring are usually due to strong winds associated with low-pressure systems and cold fronts moving southeast across California. These winds are the result of strong surface pressure gradients between the approaching low-pressure system, accompanying cold front, and higher pressure ahead of it. As the low-pressure system and cold front approaches and passes, gusty southwesterly winds typically shift to northwesterly. The strong winds can loft dust into the air and transport it over long distances, especially if soils in the region are dry. II.3 Event Day Summary The exceptional event for April 15 th and April 16, 2013, was caused by a large upper-level low over the Pacific Northwest (dry cold front) which swung through the Great Basin the evening of the 14 th through the 16 th, driving strong and gusty westerly winds across the mountains and deserts. Figure 2-8 illustrates how the entire southwestern United States was impacted by the

19 weather system responsible for the exceptional event that impacted the Brawley and Niland monitoring sites on April 15 th and April 16, FIGURE 2-8 GOES-W VISIBLE COMPOSITE APRIL 15, 2013 Fig 2-8: GOES-W visible surface composite map (13:00 PST/14:00PDT) on April 15 shows the system moving toward the Imperial Valley region, bringing strong and gusty westerly winds. FIGURE 2-9 MODIS AQUA APRIL 15 DUST CLOUD PREVAILING AND DOMINANT WIND DIRECTION Fig 2-9: MODIS Aqua April 15 showing a large dust cloud entrained by strong gusty westerly winds as the system moved into Imperial County. Prevailing and dominant wind direction as it occurred on April 15 and 16 of Strong gusty westerly winds continued on through April 16, 2013.

20 The weather system which started as early as the evening of April 14, 2013 through April 16, 2013 prompted the NWS to issue a wind advisory and a Hazardous Weather Outlook, found in Appendix A, for the whole of Imperial County. The April 15, 2013 wind advisory advised of increased and elevated winds throughout the whole day. Winds were expected to be sustained between 25 to 35mph with gusts up to 45mph potentially causing areas of blowing dust and sand. The Hazardous Weather Outlook issued for April 16, 2013, explained that the approaching dry cold front was expected to produce gusty southwest winds ranging between 25 to 35mph. As the weather system moved into Imperial County, strong winds did in fact occur. Figures 2-9 and 2-10 illustrate the prevailing and dominant wind direction and wind velocity not only for April 15, 2016 but are representative of the impact for April 16, As mentioned above, the resulting high winds from the weather system impacted the Pacific Northwest and the Great Basin causing PM 10 concentrations to elevate several air monitoring sites. FIGURE 2-10 NEXRAD WIND DIRECTION AND VELOCITY ON APRIL 15, 2013 Fig 2-10: NEXRAD base velocity image captured April 15 (13:12 PST) shows the strong winds packed by the weather system that passed through the region. Green areas over the Imperial Valley region denote winds moving toward the KYUX Yuma, Arizona radar station. Those winds continued moving eastward from Yuma at anywhere from 28 mph to over 55mph. Source: Dynamically generated through NOAA Weather & Climate Toolkit.

21 While Figure 2-11 is the graphical depiction of the chain of events as they occurred on April 15 th and April 16, 2013, the weather system in all actually began as early as April 14, 2013 (Figure 2-12). Winds begin to elevate as early as 4 AM in Riverside County on the 14 th of April with noticeable increases in wind speeds in Imperial County as early as 1 PM for the same day. In Riverside County, the Blythe Airport (KBLH) peak wind speed of 18mph was measured at 6 AM while the Palm Springs Airport (KPSP) peak wind speed of 23mph was measured at 3 PM. In Imperial County, the Imperial County Airport (KIPL) and the El Centro NAF (KNJK) measured wind speeds above 13mph with wind gusts at 21mph at 1 PM on April 14, As the weather system moved into Imperial County the elevated wind speeds and wind gusts continued on through the next day. By April 15, 2013 winds make a shift to both a prevailing and dominant westerly direction with increasing and elevated wind speeds peaking at 32mph. As the system moves through the mountain passes located west of the Brawley and Niland monitors varying elevated winds occur for both April 15 and April 16 with the entrainment of PM 10 having occurred as early as April 14, FIGURE 2-11 TIME SEQUENCE ANALYSIS APRIL 15, 2013 AND APRIL 16, 2013 Fig 2-11: Time sequence analysis for the Brawley and Niland stations identifying the wind direction with associated increases in wind speed as the weather system moved through the region on April 15, 2013

22 FIGURE 2-12 ANALYSIS HOURS RAMPING UP TO ELEVATED CONCENTRATIONS APRIL 14 THROUGH APRIL 16, 2013 Fig 2-12: Analysis demonstrating the ramping up of increasing winds causing elevated concentrations at the Niland and Brawley monitors on April 15 th and April 16, 2013 Several other stations, including the Palm Springs Airport (PSP), the Blythe Airport (KBLH) in Riverside County and the Yuma Marine Corps Air Station (KNYL) experienced similar increases in winds speeds throughout April 15 th and April 16 th, 10mph to 30mph. Like the increases in wind speeds, wind gusts similarly increased over 40mph, [Blythe Airport (KBLH)]. For detailed meteorological station graphs see Appendix B. Station Monitor Airport Met Data El Centro Naval Air Facility (KNJK) Calexico (Ethel St) Day TABLE 2-2 WIND SPEEDS ON APRIL 15 AND 16, 2013 Maximum Wind Speed (WS) (mph) Wind Direction during Max WS (degrees) Time of Max Wind Speed (PDT) 24 hr Maximum Wind Gust (WG) (mph) Time of Max WG (PDT) PM 10 correlated to time of Max Wind Speed Hourly Maximum Observed PM 10 (ug/m3) 15th : :56 N/A N/A 16th : :56 N/A N/A 15th :00 N/A N/A N/A N/A 16th :00 N/A N/A N/A N/A El Centro -9 th Street 15th :00 N/A N/A N/A N/A

23 Station Monitor Airport Met Data Brawley - (KIPL)* Westmorland - (KIPL)* Niland IMPERIAL NON-AQS SITES Bombay Beach Salton City Sonny Bono Naval Test Facility RIVERSIDE COUNTY Blythe Airport (KBLH) Palm Springs Fire Station/(PSP)** Indio (Jackson St)/(PSP)** Day TABLE 2-2 WIND SPEEDS ON APRIL 15 AND 16, 2013 Maximum Wind Speed (WS) (mph) RIVERSIDE COUNTY INDIAN TRIBAL LAND Torres - Martinez ARIZONA - YUMA Yuma Supersite/ (KNYL) MEXICALI - MEXICO Mexicali Int. Airport (MXL) Wind Direction during Max WS (degrees) Time of Max Wind Speed (PDT) 24 hr Maximum Wind Gust (WG) (mph) Time of Max WG (PDT) PM 10 correlated to time of Max Wind Speed Hourly Maximum Observed PM 10 (ug/m3) 16th :00 N/A N/A N/A 48 15th : : th : : th : :53 N/A N/A 16th : :53 N/A 78 15th :00 N/A N/A th :00 N/A N/A th 23.8 N/A 7:00 N/A N/A th N/A 1:00 N/A N/A th N/A N/A N/A N/A N/A N/A th N/A N/A N/A N/A N/A N/A th 33.3 N/A 20:00 N/A N/A th 27 N/A 2:00 N/A N/A th 26.9 N/A N/A N/A th N/A N/A N/A N/A N/A N/A th : :52 N/A N/A 16th : :52 N/A N/A 15th : : th : : th : : th : : th 18.2 N/A 16:00 N/A N/A th 10.7 N/A 3:00 N/A N/A th : : th : :55 N/A th :41 N/A N/A N/A N/A 16th :43 N/A N/A N/A N/A *Brawley sees sustained winds of >25.0 mph for multiple sequential hours; concentrations from BAM 1020 **PS Fire Station, Indio-Jackson use Palm Springs International Airport (PSP) MET Data

24 The back trajectory National Oceanic and Atmospheric Administration (NOAA) Air Resources Laboratory HYSPLIT model, 2 Figure 2-13, indicates the impact to the Brawley and Niland monitors at PM by dust particles from largely barren desert soils west of the stations. These dust particles were transported by strong winds which followed the weather system that began as early as April 14, 2013, impacting PM 10 monitors throughout southeastern California, and Arizona. The elevated levels of PM 10 concentrations measured in Riverside, Imperial and Yuma Counties illustrate the regional nature of the event (Tables 2-1 and 2-2). The chain of meteorological events resulted in steep increases in PM 10 concentrations in Imperial County, heavily impacting the Brawley and Niland monitoring sites (Figure 2-15). The entrained dust particles resulted in 24-hr FEM PM 10 concentrations (midnight to midnight) of µg/m 3 and µg/m 3 on April 15, 2016 and 24-hr FRM and FEM PM 10 concentrations (midnight to midnight) of 165 µg/m 3 and µg/m 3, respectively on April 16, BACM was overwhelmed by the intensity and duration of the meteorological event (two full days). As the weather system moves eastward and winds decline, PM 10 concentrations similarly decline (Figure 2-15). FIGURE 2-13 NOAA HYSPLIT MODEL Fig 2-13: Thirty-six hour back trajectory displaying the wind direction at the 50, 100, and 1000 meter height above grown level during April 16, 2013 ending 19:00 Coordinated Universal Time (UTC) (April 15 PDT). This graph shows the system moving into 2 The Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) is a computer model that is a complete system for computing simple air parcel trajectories to complex dispersion and deposition simulations. It is currently used to compute air parcel trajectories and dispersion or deposition of atmospheric pollutants. One popular use of HYSPLIT is to establish whether high levels of air pollution at one location are caused by transport of air contaminants from another location. HYSPLIT's back trajectories, combined with satellite images (for example, from NASA's MODIS satellites), can provide insight into whether high air pollution levels are caused by local air pollution sources or whether an air pollution problem was blown in on the wind The initial development was a result of a joint effort between NOAA and Australia's Bureau of Meteorology.

25 southern California from the Pacific Northwest. Dynamically generated through the National Oceanic and Atmospheric Administration (NOAA) Air Resources Laboratory HYSPLIT model. The HYSPLIT model, as explained in reference 2, is currently used to compute air parcel trajectories and dispersion or deposition of atmospheric pollutants. HYSPLIT's back trajectories, combined with satellite images (for example, from NASA's MODIS satellites), can provide insight into whether high air pollution levels are caused by local air pollution sources or whether an air pollution problem was blown in on the wind. FIGURE 2-14 HYSPLIT SECTIONAL VIEW FROM FIGURE 2-13 Fig 2-14: Sectional view of the thirty-six hour back trajectory displaying the wind direction at the 50, 100, and 1000 meter height during April 16, 2013 ending 19:00 Coordinated Universal Time (UTC) (April 15 PDT). FIGURE HOUR PM 10 CONCENTRATIONS AT VARIOUS STATIONS

26 PM 10 Concentration µg/m :00 06:00 09:00 15:00 18:00 21:00 03:00 06:00 09:00 15:00 18:00 21:00 03:00 06:00 09:00 15:00 18:00 21:00 03:00 06:00 09:00 15:00 18:00 21:00 4/14/2013 4/15/2013 4/16/2013 4/17/2013 Brawley Niland Indio (Jackson St) Palm Springs Fire Station Torres-Martinez Reservation Yuma Supersite Calexico (Ethel St) FRM Daily El Centro (9th St) FRM Daily Westmorland FRM Daily Fig 2-15: is the graphical representation of the 96 hour relative PM10 concentrations at various monitoring locations throughout Riverside, Imperial and Yuma counties. The graph clearly demonstrates the elevated PM10 concentrations as early as April 14, 2013 at all sites as they were impacted by the weather systems and accompanying winds.

27 III III.1 Historical Norm Analysis While naturally occurring high wind events may occur seasonally and at times frequently and qualify for exclusion under the EER, historical fluctuations of the particulate concentrations and associated winds provide insight into the frequency of events within an identified area. The following time series plots illustrate that PM 10 concentrations measured at the Brawley and Niland monitors on April 15 th and April 16, 2013, were unusual and in excess of normal historical fluctuations. The analysis, also, provides convincing evidence that the event affected air quality. Figures 3-1 through 3-3 show the time series of available FRM and BAM 24 hour PM 10 concentrations at the Brawley and Niland monitors for the four year period of 2010 through Note that prior to 2013, the BAM data was not considered FEM and was not submitted to AQS. In order to properly establish the intensity of the event, as it occurred on April 15 and April 16, 2013, 24 hour averaged PM 10 concentrations were compiled and plotted as a time series, January 1, 2010 to April 16, 2013 to provide a historical perspective of PM 10 concentrations. 350 FIGURE 3-1 BRAWLEY HISTORIC FRM AND FEM PM HR AVG CONCENTRATIONS JANUARY 01, 2010 TO APRIL 16, 2013 PM 10 Concentration µg/m /15/ /16/ /16/ Brawley FEM Brawley FRM Daily Fig 3-1: A historic comparison of PM 10 concentrations demonstrates that the April 15, 2013 measured concentration of µg/m 3 and the April 16, 2013 measured concentrations of µg/m 3 and 165 µg/m 3 from the Brawley FRM and BAM 1020 PM 10 monitors were outside the normal historic measurements

28 FIGURE 3-2 NILAND HISTORIC FRM AND FEM PM HR AVG CONCENTRATIONS JANUARY 01, 2010 TO APRIL 16, 2013 PM 10 Concentration µg/m /15/ Niland 24hr Avg Niland FRM Daily Fig 3-2: A historic comparison of PM 10 concentrations demonstrates that the April 15, 2013 measured concentration of µg/m 3 from the Niland BAM 1020 PM 10 monitor was outside the normal historic measurements FIGURE 3-3 BRAWLEY AND NILAND HISTORIC FRM AND FEM PM HR AVG CONCENTRATIONS JANUARY 01, 2010 TO APRIL 16, 2013 PM 10 Concentration µg/m Niland 04/15/ Brw 04/15/ Brw 04/16/ Brw 4/16/ Brawley FEM Brawley FRM Niland FEM Niland FRM

29 Fig 3-3: A combined historic comparison of PM 10 concentrations from both the Brawley and Niland monitors demonstrates that the measured concentrations of µg/m 3, µg/m 3, µg/m 3 and 165 µg/m 3 all are outside the normal historical norm. The time series, Figure 3-3, illustrates that of the 2,789 credible samples (1, 202 sampling days) a total of 19 violations occurred (less than 0.01% of the total samples). Of the 19 violations between January 1, 2010 through April 16, were primarily FRM violations while the remaining 17 violations were a combination of FRM/FEM violations. First quarter violations only occurred in 2012 and 2013 (one (1) each). Second quarter violations occurred in each year for 2011, 2012 and Third and fourth quarter violations occurred during the years 2011 and No violations of the standard occurred during As mentioned above FEM BAM data was not considered regulatory from 2010 to FIGURE 3-4 BRAWLEY SEASONAL COMPARISON PM HR AVG CONCENTRATIONS MARCH 1, 2010 TO MAY 31, 2013 PM 10 Concentration µg/m /15/ /16/ /16/ Brawley FEM Brawley FRM Daily Fig 3-4: A seasonal historic comparison using the months of March through May for years 2010 through 2013 (includes second quarter data) supports that the measured violations at the Brawley monitor on April 15 th and April 16, 2013 were outside the normal historical norm.

30 FIGURE 3-5 NILAND SEASONAL COMPARISON PM HR AVG CONCENTRATIONS MARCH 1, 2010 TO MAY 31, /15/ PM 10 Concentration µg/m Niland 24hr Avg Niland FRM Daily Fig 3-5: A seasonal historic comparison using the months of March through May for years 2010 through 2013 (includes second quarter data) supports that the measured violation at the Niland monitor on April 15, 2013 was outside the normal historical norm. FIGURE 3-6 NILAND SEASONAL COMPARISON PM HR AVG CONCENTRATIONS MARCH 1, 2010 TO MAY 31, 2013 PM 10 Concentration µg/m Nild 4/15/ Brw 4/15/ Brw 4/16/ Brw 4/16/ Brawley FEM Brawley FRM Niland FEM Niland FRM

31 Fig 3-6: The seasonal historic comparison using the months of March through May for years 2010 through 2013 (includes second quarter data) supports that the measured violations at both the Brawley and Niland monitors on April 15, 2013 and April 16, 2013 were outside the normal historical norm. Figures 3-4 thru 3-6, for Brawley and Niland illustrate the seasonal pattern for the months of March through May for the year 2010 thru Of the 854 credible samples for 368 sampling days only 3 measured violations occurred, two of them being the days in question. FIGURE 3-7 BRAWLEY AND NILAND HISTORICAL PM HR AVG CONCENTRATIONS JANUARY 2010 TO APRIL Percentile Count of Days <15 15<25 25<35 35<45 45<55 55<65 65<75 75<85 85<95 95< < < < <155 04/16/13 FEM /16/13 FRM < < <215 04/15/13 FEM /15/13 FEM < < <305 PM 10 Concentration µg/m 3 Fig 3-7: The combined 24-hr average PM 10 concentrations at both the Niland and Brawley monitoring sits demonstrates that the April 15, 2013 and April 16, 2013 events were in excess of the 98 th percentile. For the combined FRM and FEM annual 2010 thru 2013 Brawley and Niland dataset, the FRM concentration of 165 µg/m 3 and the FEM concentrations of µg/m 3 and µg/m 3 for Brawley and µg/m 3 for Niland are above the 99 th percentile ranking. Looking at the annual time series concentrations, the seasonal time series concentrations and the percentile ranking the April 15 th and April 16, 2013 measured violations are clearly in excess of normal historical fluctuations with seasonal violations of the NAAQS not occurring frequently. III.2 Summary

32 The information provided, above, by the time series plot, seasonal time series plot and the percentile ranking illustrate that the PM 10 concentrations and excess wind speeds observed on April 15 th and April 16, 2013 occur infrequently. When comparing the measured PM 10 levels on April 15 th and April 16, 2013 and following USEPA EER guidance, this demonstration provides supporting evidence that the measured violations measured at the Brawley and Niland monitors were outside the normal historical fluctuations. This historical concentration data and the demonstration found under the clear casual relationship support that the measured violations on April 15 th and April 16, 2013 were an exceptional event and that it affected air quality.

33 IV IV.1 Not Reasonably Controllable or Preventable Background Inhalable particulate matter (PM 10 ) contributes to effects that are harmful to human health and the environment, including premature mortality, aggravation of respiratory and cardiovascular disease, decreased lung function, visibility impairment, and damage to vegetation and ecosystems. Upon enactment of the 1990 Clean Air Act (CAA) amendments, Imperial County was classified as moderate nonattainment for the PM 10 NAAQS under CAA sections 107(d)(4)(B) and 188(a). By November 15, 1991, such areas were required to develop and submit State Implementation Plan (SIP) revisions providing for, among other things, implementation of reasonably available control measures (RACM). Partly to address the RACM requirement, ICAPCD adopted local Regulation VIII rules to control PM 10 from sources of fugitive dust on October 10, 1994, and revised them on November 25, USEPA did not act on these versions of the rules with respect to the federally enforceable SIP. On August 11, 2004, USEPA reclassified Imperial County as a serious nonattainment area for PM 10. As a result, CAA section 189(b)(1)(B) required all BACM to be implemented in the area within four years of the effective date of the reclassification, i.e., by September 10, On November 8, 2005, partly to address the BACM requirement, ICAPCD revised the Regulation VIII rules to strengthen fugitive dust requirements. On July 8, 2010, USEPA finalized a limited approval of the 2005 version of Regulation VIII, finding that the seven Regulation VIII rules largely fulfilled the relevant CAA requirements. Simultaneously, USEPA also finalized a limited disapproval of several of the rules, identifying specific deficiencies that needed to be addressed to fully demonstrate compliance with CAA requirements regarding BACM and enforceability. In September 2010, ICAPCD and the California Department of Parks and Recreation (DPR) filed petitions with the Ninth Circuit Federal Court of Appeals for review of USEPA s limited disapproval of the rules. After hearing oral argument on February 15, 2012, the Ninth Circuit directed the parties to consider mediation before rendering a decision on the litigation. On July 27, 2012, ICAPCD, DPR and USEPA reached agreement on a resolution to the dispute which included a set of specific revisions to Regulation VIII. These revisions are reflected in the version of Regulation VIII adopted by ICAPCD on October 16, 2012 and approved by USEPA April 22, Since 2006 ICAPCD had implemented regulatory measures to control emissions from fugitive dust sources and open burning in Imperial County.

34 FIGURE 4-1 REGULATION VIII GRAPHIC TIMELINE DEVELOPMENT IV.1.a Control Measures Fig. 4-1: Regulation VIII Graphic Timeline A brief summary of Regulation VIII which is comprised of seven fugitive dust rules is found below. The complete set of rules can be found in Attachment D. ICAPCD s Regulation VIII consists of seven interrelated rules designed to limit emissions of PM 10 from anthropogenic fugitive dust sources in Imperial County. Rule 800, General Requirements for Control of Fine Particulate Matter, provides definitions, a compliance schedule, exemptions and other requirements generally applicable to all seven rules. It requires the United States Bureau of Land Management (BLM), United States Border Patrol (BP) and DPR to submit dust control plans (DCP) to mitigate fugitive dust from areas and/or activities under their control. Appendices A and B describe methods for determining compliance with opacity and surface stabilization requirements in Rules 801 through 806. Rule 801, Construction and Earthmoving Activities, establishes a 20% opacity limit and control requirements for construction and earthmoving activities. Affected sources must submit a DCP and comply with other portions of Regulation VIII regarding bulk materials, carry-out and trackout, and paved and unpaved roads. The rule exempts single family homes and waives the 20% opacity limit in winds over 25 mph under certain conditions. Rule 802, Bulk Materials, establishes a 20% opacity limit and other requirements to control dust from bulk material handling, storage, transport and hauling. Rule 803, Carry-Out and Track-Out, establishes requirements to prevent and clean-up mud and dirt transported onto paved roads from unpaved roads and areas. Rule 804, Open Areas, establishes a 20% opacity limit and requires land owners to prevent vehicular trespass and stabilize disturbed soil on open areas larger than 0.5 acres in urban areas, and larger than three acres in rural areas. Agricultural operations are exempted.

35 Rule 805, Paved and Unpaved Roads, establishes a 20% opacity limit and control requirements for unpaved haul and access roads, canal roads and traffic areas that meet certain size or traffic thresholds. It also prohibits construction of new unpaved roads in certain circumstances. Singlefamily residences and agricultural operations are exempted. Rule 806, Conservation Management Practices, requires agricultural operation sites greater than 40 acres to implement at least one conservation management practice (CMP) for each of several activities that often generate dust at agricultural operations. In addition, agricultural operation sites must prepare a CMP plan describing how they comply with Rule 806, and must make the CMP plan available to the ICAPCD upon request. IV.1.b Additional Measures Imperial County Natural Events Action Plan (NEAP) On August 2005, the ICAPCD adopted a NEAP for the Imperial County, as was required under the former USEPA Natural Events Policy, to address PM 10 events by: Protecting public health; Educating the public about high wind events; Mitigating health impacts on the community during future events; and Identifying and implementing BACM measures for anthropogenic sources of windblown dust. Smoke Management Plan (SMP) Summary There are 35 Air Pollution Control Districts or Air Quality Management Districts in California which are required to implement a district-wide smoke management program. The regulatory basis for California s Smoke Management Program, codified under Title 17 of the California Code of Regulations is the Smoke Management Guidelines for Agricultural and Prescribed Burning (Guidelines). California s 1987 Guidelines were revised to improve interagency coordination, avoid smoke episodes, and provide continued public safety while providing adequate opportunity for necessary open burning. The revisions to the 1987 Guidelines were approved March 14, All air districts, with the exception of the San Joaquin Valley Air Pollution Control District (SJAPCD) were required to update their existing rules and Smoke Management Plans to conform to the most recent update to the Guidelines. Section of Title 17 specifies the special requirements for open burning in agricultural operations, the growing of crops and the raising of fowl or animals. This section specifically requires the ICAPCD to have rules and regulations that require permits that contain requirements that minimize smoke impacts from agricultural burning. On a daily basis, the ICAPCD reviews hourly surface meteorological reports from various airport