## Chapt er Two – B a s e line and Natur a l Visibility Conditions and Uniform Rate of Progress

2.1 INTRODUCTION

2.2 BASELINE CONDI T IONS F O R THE JARBIDGE WILDERNESS AREA

2.3 NATURAL CONDI T IONS F O R TH E JARBIDGE WILDERNESS AREA

2.4 UNIFORM RATE OF PROGR ESS GLI D EPATH TO NATURAL CONDITIONS IN 2064

2.5 HAZE I M PACTI N G PARTICLES – BASELINE P E RIOD

2.5.1 Aerosol Com p osition for the Jarbidge W ildernes s Area 2.5.1.1 Summ ary of Aerosol Composition 2.5.1.2 20 Percent Worst Days 2.5.1.3 20 Percent Best Days 2.5.1.4 All IMPROVE Sa m p le Days 2.5.2 Comparison of Baseline Extinction for Best and W o rst Days 2.5.3 Aerosol Pollutant Trends



### 2.6 REFERENCES

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-12.1 INTRODUCTION

The goal of the Regional Haze Rule (RHR)(64 FR 35714) is the restoration of natural visibility conditions in the 156 mandatory Class I areas identified pursuant to the 1977 Clean Air Act Am endm ent s . Federal visibility regulations detail how to establish goals to restore visibility to natural conditions by the year 2064 fo r the Class I areas. These regul ations also require states to calcu late b a selin e, current, and natu ral vis i bility conditions, which in tu rn are used to calcu late the uniform rate of progress per year to achieve natural conditions by 2064.

Natural v i sibility is d e te rm ined by estim ating th e natur a l co ncentr ation s of visibility im pairing pollutants and then calculating to tal light extinction. Baseline visi bility is the starting point for the im provem e nt of visibility conditions. The baseline for this regional haze state im ple m entation plan (SIP) is the y e ars 2000 thro ugh 2004. Current con d itions are assessed every five y ears as p a rt of the SIP review , where actual progress in reducing visibility im pairm e nt is com p ared to the reduc tions comm itted to in the SIP.

The baseline and current visibi lity co nditions f o r the Jarb i dge W ilderness Area are based on

m easure m ents of particulate air pollution at the JA RB1 Interagency Monitoring of Protected Visual Environm ents (IMPROVE) monitoring site, as discussed in Chapter One. The revised IMPROVE algorithm was used to calculate th e Haze Index fo r the Jarbidg e W ildernes s Area.

This chapter presents an d inte rpre ts the IMPROVE m onitorin g data to ide n tif y the ro le of individual com ponents in visibility impairm ent at JARB1. The following chapters will present and inte rpre t the em issio n s data and modeling results that, with th is chapter, are the technica l basis for determ ining Nevada’s reasonable pr ogress. The following paragraphs present a synopsis of the analyses of th e IMPROVE monitoring data.

Analyses of the JARB1 monitor data have id entified a baseline visi bility condition of 12.07 deciviews (d v) and natu ral vis i bility conditions o f 7.87 dv for the 20 percent worst days. The

com p arison of the initial baseline co nditions to n a tural vis i bility cond ition s indicates the am ount of i m provem e nt necessary to a ttain natural visibili ty by 2064. The uniform rate of progress glidepath indicates a unifor m rate of progre ss value of 11.09 dv for 2018 worst days leading to restoration of natural visibility conditions by 2064.

Organic m a tter carbon and elem ental carbon extincti on account for m o re than 45 percent of the total average annual rec onstructed extinction at the JARB1 m onitor for the 20 percent worst days of the baseline. In addition, coarse and fine particle m a ss extinction acco unt for an ad dition a l 30 percent of the average annual extinction at JARB1. Approxi m a tely 20 percent of the annual extinction budget is due to the form ation of ammonium sulf ate and amm o nium nitrate due to

em issions of sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ) from predom inantly anthropogenic sources. These conclusions support the observa tions of Nevada Divi sion of Environmental Protection (NDEP) staff, presented in Chapter One, regarding the sign if icant con t rib u tion of windblown dust and natural fire em issions to visibi lity im pairm e nt at the Jarbidge W ilderness Area.

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-22.2 BASELINE CONDITI ONS FOR TH E JARBIDGE WILDERNESS AREA

Baseline visibility is the annual average of th e on-site IMPROVE m onito ring data for the leastim paired days (i.e. the 20 percent best days or “best days”) and m o st im paired days (i.e. the 20 percent worst days or “worst days”) for th e years 2000 through 2004, as specified in 40 CFR 51.308(d)(2 )(i). Baselin e visib i lity is equivalent to current v i sibility cond itions for this initial review period and is the refe rence point against w h ich visibi lity im prove ment is tracked.

Nevada has estab lished baseline vis i bility conditi ons f o r the best and wor s t vis i bility days at the Jarbidge W ilderness Area using data from IMPROVE monitor JARB1. The average was calculated f o r the years 2000 throug h 2004 (the 2000 data is invalid fo r JARB1 as it fails to m e et USEPA’s data com p lete ness cr ite ria ) f o r the bes t and worst days. The baseline calculations were

m a de in accordance with 40 CFR 51.308(d)(2 ) and USEPA’s Guidance for Tracking Progress Under the Regional Haze Rule (EPA-454/B-03-004, Septem ber 2003).

The baseline conditions are the average of th e an nual haze in dex calcu lated from the IMPROVE monitor data over the five-year baseline peri od 2000 through 2004 for both the 20 percent worst (12.07 dv) and 20 percent best (2.56 dv) days. F i gures 2-1 and 2-2 are p hotographs of reference vistas representative of baseline extinction conditions for the best and worst days, respectively, at the Jarbidge W ilderness Area.

2.3 NATURAL CONDITI ONS FOR THE JARBIDGE WILDERNESS AREA

Natural v i sibility rep r es ents th e vis i bility c ondition that would be observed in the absence of hum a n-caus e d im pairm e nt. The natu ral cond ition fo r each Class I area represents the visibility goal expressed in deciviews for the 20 percent wo rst and the 20 percent be st days that would exist if there were only n a tura lly oc c u rring im pairm e nt. The 20 percent worst days natural conditions correspond to the long-term natural vi sibility goal to be reached by 2064. 40 CFR 51.308(d)(1) Each state must estim ate natural visibil ity levels for Class I ar eas within its borders in consultation with federal land m a nagers (FLMs) and other states. 40 CFR 51.308(d)(2)

Natural background visibility is based on annual average concentrations of fine particle

com ponents. The natural conditions estim ates were calculated consistent w ith USEPA’s Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Rule (EPA454/B-03-005, Septem be r 2003). The natural backgr ound visibility for Jarbidge is 7.87 dv for the 20 percent worst days and 1.14 dv for the 20 percent best days.

Figures 2-3 and 2-4 are photographs of reference vistas repres entative of natural extinction conditions for the best and worst days at the Jarbidge W ilderness Area.

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-3FIGURE 2-1

REFER E NC E VISTA OF THE JAR B IDGE W I LDER NESS AREA FOR BASE LINE BEST DAYS

Reference Vista : Ma ry’s River Peak

Photo taken at 3:00 pm

Haz e Index (HI) = 3 deciview

B ext = 13 Mm -1

Visual Range = 300 km / 186 m i

FIGURE 2-2

REFER E NC E VISTA OF THE JAR B IDGE W I LDER NESS AREA FOR B A SE LINE WOR S T DAYS

Reference Vista : Ma ry’s River Peak

Photo taken at 3:00 pm

Haz e Index (HI) = 12 d e ciview s

B ext = 33 Mm -1

Visual Range = 120 km / 75 m i

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-4FIGURE 2-3

REFER E NC E VISTA OF THE JAR B IDGE W I LDER NESS AREA FOR NATURAL C O NDITIONS BE ST DAYS

Reference Vista : Ma ry’s River Peak

Photo taken at 9:00 am

Haz e Index (HI) = 1 deciview

B ext = 11 Mm -1

Visual Range = 350 km / 218 m i

FIGURE 2-4

REFER E NC E VISTA OF THE JAR B IDGE W I LDER NESS AREA FOR NATURAL CONDITIONS WORST DAYS

Reference Vista : Ma ry’s River Peak

Photo taken at 9:00 am

Haz e Index (HI) = 8 deciview s

B ext = 23 Mm -1

Visual Range = 170 km / 106 m i

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-52.4 UNIFORM RATE OF PROGRESS GLID EPATH TO NATURAL CONDITI ONS IN 2064

Each state must set goals that provide fo r reasonable progress to wards achieving natural visibility conditions by 2064. The reasonable prog ress goals must: 1) provide for improvem e nt in visibility for the m o st im paired days over th e period of the im ple m entation plan; and 2) ensure no degradation in visibility for the least im paired days over the sam e period. States are directed to graphically show a unifor m rate of progress (URP) toward natural vi sibility conditions for each Class I area within the State. Th e re vis e d IM PROVE II algorithm was used for th e calcu lation of the URP glidepath fo r the Ja rbidg e W ildernes s Area.

A graph depicting the w o rst days glidepath for the Jarbidge W ilderness Area was developed in accordan ce with USEPA guidance for track ing progress ( Guidance for Setting Reasonable Progress Goals Under the Regional Haze Rule , June 1, 2007), using data collected from the IMPROVE monitor JARB1. The glidepath is one of the ind i cato r s used to set reason able progress goals and is sim p ly a gr aph portraying a straight line draw n f r om the lev e l of visibility im pair m e nt for the worst days baseline period to the natural background le vel with 2064 as the attainm e nt date.

The URP is determ ined by the following equation, wh ich calculates the slope of the glidepath in deciviews per year: URP = (Baseline Condition – Natura l Condition ) / 60 years URP = (12.07 dv – 7.87 dv) / 60 years URP = 0.07 dv / year reduction

The uniform progress needed by 2018, the end of the first planning period, to achieve worst days natural vis i b ility conditions by 2064 is calcul ated by m u ltiplying the URP by the number of years in the first planning pe riod (i.e. 2004 to 2018), as follow s : 2018 URP = (URP) x (14 years) 2018 URP = 0.07 dv / year x 14 years 2018 URP = 0.98 dv reduction

Table 2-1 provides the URP data for the worst days and identifies the baseline for the best days. The baseline visibility for the 20 percent wo rst days at the Jarbidge W ilderness Area is calculated to be 12.07 dv. For the ba seline 20 percent best days, visi bility is calculated to be 2.56 dv. The URP glidepath is show n on Figure 2-5, which depicts the observed annual baseline visibility conditions by solid diam onds with th e worst days baseline shown by the line through the solid diamonds. The glidepath for a URP towa rd reaching the goal of natural cond itions is represented by the sloping line with the open tria ngles id entif ying the URP at five year intervals. Natural conditions for the worst days are shown by the horizontal line in th e m i ddle of the graph. The figure also shows the observe d annual baseline conditions fo r the 20 percent best days by open diam onds with the baseline shown by th e short line through the open diam onds. The reasonab l e p r ogress go al must en sure no degradation in visibilit y for the best days over the planning period.

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-6TABLE 2-1

UNIFORM RATE OF P R OGRESS FOR T H E JARBIDGE W I LDERNESS AREA

C l ass I A r e a 20 % W o r s t Da y s Ba s e l i n e C o n d it

io n (d v ) 20 % W o r s t D a y s 201 8 Un i f o r m P r

ogr es s Go a l ( dv) 201 8 Re d u c t i o n N e ed ed fo r 20 % W o r s t Da y s (d v ) 20% W o r s t D a y s 20 64

Na t u

r a l C o nd i t i ons (d v ) 20 64 Re d u c t i o n Ne e d e d f

o r 20 % W o r s t D a y s (d

v ) 20 % B e s t Da y s B a s e lin e C o n d iti o n (d

v )

Ja

rb i d g e W i l d er ne ss A r ea 12

. 0 7 1 1. 0 9 0

. 9 8 7. 8 7 4. 20 2

. 56

FIGURE 2-5

UNIFORM RATE OF P R OGRE SS GLIDEPAT H FOR THE JARBIDGE W I LDERNESS AREA

U n i f o r m R a t e of P r o g res s G l i d ep a t h J a rb i d ge W i l d ern ess A rea - 2 0 P ercen t B e s t a n d W o rs t Da y s

12

. 0 7 11

. 7 9 11

. 4 4 11

. 0 9 10

. 7 4 10

. 3 9 10

. 0 4 9. 69 9. 34 8. 99 8. 64 8. 29 7. 8 7

0 2 4 6 8 10 12 14 16

20 00 20 04 20 08 20 12 20 16 20 20 20 24 20 28 20 32 20 36 20 40 20 44 20 48 20 52 20 56 20 60 20 64

Ye ar

B a se l i n e O b s 2 0 % W 20 00

- 200 4 B a s e l i n e 2 0 % W G lid e P a th

B a se l i n e O b s 2 0 % B 20 00

- 200 4 B a s e l i n e 2 0 % B N a tu r a l C o n d itio n s 20 18 - E n d o f

1s t P l a n n i n g Pe r i o dHaze Index(Deciview)

2.5 HAZ E IMPACTI N G PARTI C LES – BASELI NE PERIOD

Som e of the fine particles that com p ose aeroso l s ab sorb light, while others reflect or scatter light, resulting in light extinction be tween the viewer an d the light s ource. The IMPROVE monitor

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-7collects a 24 -hour sam p le of these particles on to a filter, and they are an aly zed at a lab o ratory to determ ine the standard com ponents of the aerosol extinction.

Monitored Com ponents The m onitored concentrations of PM 10 are divided into six m a jor com pone nts, the first five of which are assum e d to be PM 2. 5 and the sixth is P M 2. 5- 10 . The m onitored species are listed below by identifier with the common na m e in parenthesis.

• SO 4 (sulfate )

• NO 3 (partic u late n i trate)

• OC (organic carbon)

• EC (elem e ntal carbon)

• OF (other fine particulate or soil)

• CM (coarse m a tter) The concentrations of th ese species are used in conjunction with the IMPROVE equation to calculate the light extinction.

Em ission Species The statewide em ission inventory of pollutants that were us e d in the em ission scen ar ios f o r this SIP include:

• SO 2 (Sulfur dioxide)

• SO x (Sulfur oxides)

• NO x (Nitrogen oxides)

• POA (Prim a ry organic ae roso l)

• EC (Elem e ntal carbon)

• PMF (Particulate m a tter f i ne)

• PMC (Particulate m a tter coars e )

• NH 3 (Amm onia)

The baseline em issions and em ission projections are dis c usse d in deta il in Chapter Thr ee.

Extinction S p ecies Visibility co nditions are then es tim ated by relating the IMPR OVE 24-hour average P M m a ss

m easure m ents (i.e. concentration data for the spec ies listed above) to the P M com pone nts of light extinction as identified in the IMPROVE equation. The extinction com ponents are listed below. The bold text indicates how the m oni tored extinct ion com ponents will be identif i ed in the

rem a inder of the SIP.

• Ammonium sulfate [(NH 4 ) 2 SO 4 ] or SO 4

• Particulate ammonium nitrate [(NH 4 )NO 3 ] or NO 3

• Organic m a tter carbon [ OMC ]

• Elem ental carbon [ EC ]

• Fine soil [ SO I L ]

• Coarse m a tter [ CM ]

• Sea Salt

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-82.5.1 Aerosol Composition for the Jarbidge Wilderness Area

Analyses of the IMPROVE m onitor data provides im portant insight to the rela tive im portanc e of the com ponents of m eas ured visibility im pairi ng pollutants. The m onitoring data for the 20 percent worst, 20 percent best , and IMPROVE s a m p le days were analyzed on an annual, monthly, and daily basis to evaluate the cause s of visibility impairm ent during the baseline period.

2.5.1.1 Summary of Aerosol Composition

This section describes the aer osol composition observed at th e JARB1 IMPROVE m o nitor during the baseline period. The following sections present the m onitoring data for the 20 percent worst days, 20 percent best days, and all IMPROVE sa m p l e days.

Organic matter carbon (OMC) is the m o st im portant contri butor to fine particulate m a ss and light extinction on the most im paired days and for all IMPROVE sa m p le days. OMC is also a significant contributor on the le ast impaired days of the baselin e period at JARB1. Elevated levels of OMC and EC and their seasonal sign ature suggest impact from fire and biogenic sources, which are signif i cant natural sources of prim ary organic aerosol (POA) and volatile organic compounds (VOCs), com ponents of OMC. Anthropogenic em issions contributing to OMC include carbon from com bustion of foss il fuels and wood burning, but are not likely significant sources of OC e m issions at th is ru ral site. Howev e r sign if ican t visib i lity impacts due to OC e m issions from na tural fire events ar e common at the Jarbidge W ilderness Area and explain the large daily, seasonal, and annual va riations of the reconstructed OMC extinction described in the next sections.

Coarse matter (CM) or particulate m a tter with part icles having diam eters between 2.5 and 10

m i crons is the second most im portant contributor to reconstructed extinction for the worst days of the baseline period. CM has a relatively sm all contribution to visibility im pairm e nt on the best days, b u t is a s i gnif i cant contr i b u tor to v i sib i lity im pairment f o r IMP R OVE sample days. The light extinction efficiency of CM is very low com p ared to the extinction efficiency for sulfate, nitrate, and carbon, as described in Ch apter One. The significant CM contributions to reconstructed extinction suggest the seasonal im portance of lo cal and regional transport of particulate m a tter due to naturally occurring windblown dust events.

Ammonium sulfate (SO 4 ) or sulfate is an im portant contributor to visibility im pairm e nt at JARB1 for the worst days and IMPROVE s a m p le days. SO 4 is the most signif i cant con t rib u tor on th e best days. S u lfate particles are form ed in the atmosphere from SO 2 e m is sions. Sulfate particles occur as hydrogen sulfate, ammonium bisulf ate and ammonium sulfate depending on the availability of a m m onia in the atm o s phere. Although SO 4 contributions show som e seasonal incre a ses du ring th e summ er m onths, the la ck of daily va riab ility sugg ests the sulf ate contributions are influenced by regional transport rather than local sources.

Soil (SOIL) or particulate m a tter with particles having diam eters less than 2.5 m i crons is a m i nor contributor to reconstruc ted extinction for the worst, best and IMPROVE samp le days of the baseline period. Episodes of relatively high SO IL contribution coupled with relative high CM

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-9contributions m a y be indicative of local and regi onal seasonal transport of particulate m a tter due to windblown dust even ts. Occasion a lly, elevated SOIL can be attribu t ed to long-ran g e transpo r t of

interna tio nal dust epis odes or iginating outside the US.

Elemental carbon (EC) is a m i nor contributor to visibili ty im pairm e nt at JARB1 f o r the worst, best and IMPROVE sample days of the baseline pe riod. The light extinction efficiency of EC is high com p ared to the extinction efficiency for su lfate, nitrate and carbon, as described in Chapter One. Common sources of EC e m is sions are fire , including agricultural burning, prescribed fire, and natur a l f i re, as we ll a s incom p lete com busti on of fossil fuels. The seasonality and common trend shared with OMC extinction suggest fire em issions m a y also be the dom i nant source of EC extinction at JARB1.

Ammonium nitrate (NO 3 ) or nitrate is a m i nor contributor to r econstru c ted extinc tion f o r the worst, best and IMPROVE sa m p le days of the baseline period at JARB1. However, NO 3 is a significant contributor for som e individual days. NO 3 is for m ed in the atmosphere by the reaction of ammonia (NH 3 ) and nitrogen oxides (NO x ). NO 3 f o rm ation is lim ited by the availability of a m m onia and tem p erature. Amm o nia preferentially reacts with SO 2 and sulfate before reacting with NO x . Particle nitrate is form e d at lower temperatures, so NO 3 levels are lower in the summer m o nths and higher in th e winter m onths. Therefore the relativ e NO 3 contr i bution to visib i lity im pairm e nt is seasonal as identified below. NO x em issions are the result of fossil fuel com bustion by point, area, on-road, and off-road m o bile sources. The relatively m i nor contribution of NO 3 to reconstructed extincti on at JARB1 suggests that for m ation is lim ited by both the availabil ity of ammonia and the paucity of NO x sources in th is rural setting.

Sea Salt (SEA SALT) is a trace contributor to r econstructed extinction at JARB1. The new IMPROVE equation uses the chlorine ion from r outine IMPROVE measurem ents to calcu late sea salt levels, accounting for the occasional cont ribution of SEA SALT to extinction at JARB1.

2.5.1.2 20 Percent W o rst Days

Figure 2-6 shows the annual rec onstructed ligh t extinc tion o v er the baseline period based on monitor data from JARB1 site for the 20 percen t worst days. The vari ability of annual worst days reconstructed light extinc tion is nearly 8 M m -1

. The line graph shown as Figure 2-7 shows the in dividual components of the reconstructed light extinction over the baseline period based on JARB1 IMPROVE data for the 20 percent worst days. OMC is the m o st significant co ntribu tor to visibility im pair m e nt at JARB1 for the baseline period, followed by CM and SO 4 . SOIL, EC, and NO 3 are less significant but sub-equal contributors to visibility imp airm ent for the baseline period.

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-10FIGURE 2-6

ANNUAL RECONST R UCT E D E X TINC TION FOR WO RST DAYS OF THE BASELINE PERIOD

The baseline period annual variation for OMC is nearly 7 Mm -1 , indicating the large range of annual effects produced by fire em issions, one of the dom inant sources of OMC. 2002 was a bad fire year in the western US, as reflected on Figure 2-7 by th e OMC trend. The baseline period variation for CM is over 2 Mm -1 , suggesting the range of effe cts produced by em issions from localized wind events, especially du ring seasonal drought co nditions. Th e rem a ining

com ponents show less variability during the baseline period.

FIGURE 2-7

ANNUAL RECONST R UCT E D E X TINCTION BY S P EC IES FOR W O RST DAYS OF B A SELINE P E RIOD

Figure 2-8 displays the monthly distribution of the reconstructe d extinction for the 20 percent worst days of the baseline period for the Jarbidge W ilderness Area. The worst days are generally summer events, occurring during the period m i d-Ma rch to the end of Septem ber of ea ch year

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-11with a few exceptions. Fires, dust events, and p hotochem i cal processes are elevated during this tim e fram e, which m a xi m i zes OMC and EC concen trations, C M and SOIL concentrations, and secondary particulate form ation.

FIGURE 2-8

MONTHL Y DISTRIBUTION OF WORS T DAYS OF B A SE LINE PERI OD

Daily re cons truc ted light extinc ti on for the 20 percent worst days of the bas e line y ears at JARB1 is presented in Figure 2-9 and shows OMC, and/ or CM are generally th e largest com ponents of visibility im pairm e nt on the worst days at the Jarbidge W ilderness Area. SOIL, NO 3 , and SO 4 are significant com pone nts for a handful of days.

FIGURE 2-9

DAILY RECONSTRUCTED LI GHT EXTINCTION FOR W O RST DAYS OF B A SELINE P E RIOD

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-122.5.1.3 20 Percent Best Days

The bar graph shown in Figure 2-10 shows the re constructed light extinction over the baseline period for the 20 percent best days based on data from JARB1. Note the baseline period annual variation is less than 0.5 Mm -1 for the best days, much less th an the va ria b ility shown f o r the worst days.

FIGURE 2-10

ANNUAL RECONST R UCT E D E X TINCTION FOR BEST DAYS OF BASE LINE PERI OD

The line graph in Figure 2-11 shows the indivi dual com ponents of th e reconstructed light extinction over the baseline period for the 20 percent best days at JARB1. SO 4 and OMC are the most significant contributors to visibility im pa irm e nt for the best days of the baseline period, followed by sub-equal contributions f r om NO 3 , EC, and CM. SOIL is a minor contributor to visibility im pairm e nt for the best days. SO 4 has approxim a tely 0.5 Mm -1 variation, w h ile OMC has approxim a tely 0.2 Mm -1 variation for the best days of the baseline period.

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-13FIGURE 2-11

ANNUAL RECONST R UCT E D E X TINCTION BY S P EC IES FOR BEST DAYS OF BASE LINE PERI OD

Figure 2-12 displays the monthly distribution of the reconstructi on extinction for the 20 percent best days of the baseline period for JARB1. The best days are ge nerally winter events occurring from October to May of each year, when fires, du st even ts, an d photochem i cal processes are at a mi n i mu m. FIGURE 2-12

MONTHL Y DISTRIBUTION OF B E ST DAYS OF BASELI NE PERIOD

Daily re cons truc ted light extinc ti on for the 20 percent best days of the baseline period at JARB1 is presented in Figure 2-13 and shows OMC and/or SO 4 are generally the la rgest com ponents of visibility im pairm e nt on the best days at th e Jarb idge W ildern e ss Area. N O 3 , CM, and Sea Salt are significant com pone nts for a handful of days.

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-14FIGURE 2-13

DAILY RECONSTRUCTED LI GHT EXTINCTION FOR BEST DAYS OF BASE LINE PERI OD

2.5.1.4 All IMPROVE Sample Days

Figure 2-14 shows the annual rec onstructed light extinction over the baseline period based on monitor data f

r om JARB1 site f o r a ll IMPROVE sam p le days. The variability of the IMPROVE

sam p le days reconstructed light extinction is app r oxim a tely 2 Mm -1

.

FIGURE 2-14

ANNUAL RECONST R UCT E D E X TINCTION FOR IMPROVE SAMPLE DAYS OF B A SELINE P E RIOD

The line graph shown in Figure 2-15 show s the individual com ponents of the annual reconstructed light extinction over the baseline period based on JARB1 I M PROVE data for the IMPROVE sam p le days. OMC is the m o st signifi cant contributor to visibility im pairm e nt at JARB1 for the IMPROVE sam p le days of the baseline period, followed by sub-equal C M and

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-15SO 4 . SOIL, EC, and NO 3 are m i nor contributors to visibil ity impairm ent for the bas e line period IMPROVE sam p le days.

FIGURE 2-15

ANNUAL RECONST R UCT E D E X TINCTION BY S P EC IES FOR IMPROVE SAMPLE DAYS OF B A SELINE P E RIOD

The baseline period annual variation for OMC is nearly 1.5 Mm -1 , indicating the range of annual effects produced by fire em issions. The baseline period variation for CM and SO 4 is less than 1 Mm -1 . The rem a ining components show less vari ability during the ba seline period for the IMPROVE sam p le days.

Figure 2-16 displays the monthly reconstructed extinction for the IMPROVE sa m p le days of the baseline period for the Jarbidge W ilderness Area, while Figure 2-17 presents the daily reconstructed light extinction fo r the IMPROVE sam p le days of the baseline period. These figures show pronounced seasonality of the recons tructed extinctions w ith the highest m onthly extinc tions occurr ing in the summ er months and the lowest monthl y ex tin ctions o ccur r ing in the winter m onths. The visibility effects of CM, SOI L , EC, and OMC extinction overwhelm the contributions of SO 4 and NO 3 extinction, especially during the summer m o nths. SO 4 contributes more to visibility im pairm e nt during the sp ring and early summer m ont hs, contributing less during the rem a ining m o nths of th e year. The contribution of NO 3 to visibility im pair m e nt is greatest during the winter m onths and is significan t for som e days. These effects are even m o re pronounced for the daily reconstructed extinctions presented in Figure 2-17.

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-16FIGURE 2-16

MONTHL Y RECONST R UCT E D E X TINCTION FOR IMPROVE SAMPLE DAYS OF B A SELINE P E RIOD

FIGURE 2-17

DAILY R E CONS TRUCTED E X T I NCTION F O R IMPROVE SAMPLE DAYS OF B A SELINE P E RIOD

2.5.2 Comparison of Baseline E x tinction for Best and Worst Days

Figure 2-18 com p ares the averag e baselin e extinc tion for the 20 percent wo rst days with the 20 percent best days from the JARB1 monitor. All com ponents of extinction are less on the best days, but significant reductions in CM and OMC extinc tion r e sult in the m a jority of the visib i lity im prove m e nt on the best days, confirm i ng the signifi cant role of natural e m issions in visibility im pairm e nt at the Jarb id ge W ilderness Area.

Table 2-2 presents the monitored contributions to reconstructed light extin ction by sp e c ies f o r the m o st and least im paired days of the ba seline period based on da ta f r o m the W R AP’s

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-17Technical Support System. For the most im pair ed days, OMC and CM, on average, contribute nearly two thirds of the extin ction. Sources of OMC and CM em issions are predom i n antly natural and uncontrollable, as are SOIL and EC em ission sources. SO 4 and NO 3 contribute m o re than 15 percent and less than 5 percent, respecti v e ly to recons truc ted extin c tion f o r th e m o st im paired days. For the least im paired days, SO 4 and NO 3 contribute m o re than 40 percent and nearly 10 p e rcent, respe c tive l y to th e r econstructed extinction. Sources of SO 2 and NO x em issions are largely anthr opogenic and controllable.

FIGURE 2-18

COMPARIS ON OF BASELINE EXTINCTION FOR W O RST AND BE ST DAYS OF B A SELINE P E RIOD

J a r b id g e Wi ld e r n e ss A r ea C o m p a r i s o n o f B a s e l i n e P e r i o d ( 2000

- 2 004) E x t i n c t i o n o n B e s t a n d W o r s t D a y s

0 5 10 15 20 25

20% W o rs t D a y s 20 % B e s t D a y sExtinction (Mm-1) S e a S a lt E x tin c tio n CM Ex tin c tio n S o il Ex tin c tio n
E C Ex tin c tio n O M C Ex tin c tio n
N O 3 Ex tin c tio n S O 4 Ex tin c tio n

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-18TABLE 2-2

MONITOR E D CONTR I BUTIONS TO ANNUAL RE CONSTRUCTE D EXTINCTI ON BY SPECIES FOR BASELINE PERIOD

Ye a r SO 4 E x ti n c tio n NO 3 Ex t i n c t i o n OM C E x tin c t io n EC Ex t i n c t i o n SO I L Ex t i n c t i o n CM Ex t i nc t i o n S e aS al t Ex t i n c t i o n

200 1 14. 6 % 3

. 5 % 3 8

. 6% 8. 4 % 10. 4 % 2 4. 2 % 0

. 3% 200 2 11. 5 % 5

. 6 % 4 8

. 4% 6. 5 % 10. 9 % 1 7. 1 % 0

. 0% 200 3 17. 3 % 3

. 1 % 4 0

. 8% 6. 3 % 7. 7% 24. 8 % 0

. 0 % 200 4 23. 6 % 5

. 7 % 3 2

. 4% 5. 0 % 9. 7 % 2 3 .0 % 0 .7 % A v era g e 1 6. 7 % 4. 5% 4 0

. 0 % 6

. 5 % 9

. 7 % 22. 3 % 0. 3%

2 0 0 1 4 5 .9 % 1 2

. 3 % 2 3 .0 % 8 .5 % 3 .1 % 7 .2 % 0 .0 % 200 2 40. 3 % 8

. 3 % 2 5

. 9% 9. 4 % 2. 9 % 1 1 .9 % 1 .4 % 2 0 0 3 3 4 .2 % 9 .2 % 3 1

. 5 % 1 1 .0 % 2 .7 % 9. 6 % 1. 7 % 200 4 43. 3 % 9

. 3 % 2 4

. 7% 8. 9 % 2. 4% 8

. 2% 3

. 1% Av e r a g e 4 0

. 9 % 9

. 8 % 2 6 .3 % 9 .4 % 2

. 8 % 9 .2 % 1 .6 % 20 P e ce nt W o rs t D a y s

20 Pe r c en t B e s t D a y s

2.5.3 Aerosol Pollu tant Trends

Figure 2-19 presents the annual m onitored light extinction in deci views for the 20 percent worst and best days and a corresponding trend line. The long-term annual extinction trend for the 20 percent worst days, shown by the diam onds, is e ssentially flat, although there are large annual variations. The trend for the 20 percent best days, shown by the triangles, has a downward trend indicating improvem e nt in the long- term visibility conditions at th e Jarbidge W ilderness Area for the best days.

Figure 2-20 shows the annual extinction data on the 20 percent worst day s for seven h aze causing pollutants from JARB1 for the year s 1992 through 2005 with a corresponding colorcoded, long-term trend line. The graphs utilize valid data from years pr ior to and including the baseline period. Data from the years 1996, 1997, and 2000 did not m eet the USEPA data

com p leteness requirem e nts (75 percent for the year and 50 percent fo r ea ch quarter) a nd therefore don’t have calculate d annual concentrations.

Exam ination of the data provides insight into the long-term trends of haze causing pollutants at the JARB1 IMPROVE monitor. S O 4 and NO 3 , consider ed to be em itted by m o stly anthropogenic sources, have sli ght downward trends, although NO 3 is esse ntia lly f l at. These data suggest slight im provem e nt in the long-term control of SO 2 and NO x em issions impairing visibility at the Jarbidg e W ild erness Area for the worst days.

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-19OMC extinction, despite its large annual variation, has a well-def ined, upward long-term trend, suggesting a larger ro le of fire em iss i ons in re gio n al haze with tim e. EC, also though t to be largely due to fire em issions, has a flat trend.

FIGURE 2-19

ANNUAL I M PROVE R E CONSTR UC TED EXTINCTION TRENDS FOR WORS T AND BES T DAYS

J A RB I D G E W I L D ERNE S S A R EA I M P R O V E E x t i nct i on T r en ds f o r 2 0 P e r cen t W o r s t a n d B e st D a y s [ i nv

a l i d da t a f o r

1996, 19 97, a n d 2000]

0 2 4 6 8 10 12 14 16

19 91 19 92 19 93 19 94 19 95 19 96 19 97 19 98 19 99 20 00 20 01 20 0 2 2 0 0 3 20 04 20 0 5

Ye a rHaze Index(Deciview)

Ba s e lin e O b s 2 0 % W B a sel i n e O b s 2 0 % B

CM, also showing significant a nnual variations, has a long-term downwar d trend. SOIL shows an opposite, upward trend, although not as pronounced, perhaps due to increasing contributions to interna tio nal transpor t resulting f r o m clim ate change and increasing popul ation pressure in the developing world.

Continued improvem e nt s in regional sulfate and, to a lesser degree, nitrate le vels are expected in the western states as further cont rols are realized on m a jor so urces as the result of BART and the im ple m entation of other regional haze program s, as well as co mpliance with ozone and PM 2. 5 standard s. We expect these regional downward trends in SO 2 and NO x em issions will provid e continued visibility im provem e nt.

However, the trends in OMC and SOIL are not so encouraging. The wide variations in annual concentrations on the 20 percent worst days m a y be related to altern ating drought and norm a l precipitation conditions with corr esponding increases in carbon em issions due to wildfires and

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-20increases in dust (e.g., C M and SOIL) em issions resulting from increasingly prevalent dry and dusty conditions.

FIGURE 2-20

JARBIDGE W I LDERNESS AREA SPECIATE D EXTINC TION TRE NDS F O R WORST DAYS

J A RB IDG E W I LDE RNES S A R EA S p eci a t e d I M P R O V E E x t i n ct i o n T r en ds f o r 2 0 Per cent W o r s t D a y s [inv

a l i d

da t a

f o r 1 996, 1997, a nd 2000]

0 2 4 6 8 10 12 14 16 18 20

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 20 02 2003 2004 2005

Ye a rExtinction (Mm-1) S O 4 Extinc t ion
N O 3 Exti n c ti o n O M C E x ti n c ti o n EC Extinc t ion
S o il Extinc tion
CM E x ti n c ti o n S e a S a l t Ex t i n c ti o n

NDEP has analyzed the JARB1 monitor d a ta ; ide n tif ied th e b a seline and natura l vis i b ility conditions; identified a 2018 URP va lue of 11.09 dv for the worst days; and determ ined OMC and CM extinction contribute the m a jority of visib ility im pairm e nt on the worst days. These data suggest that visibility im provem e nt due to em issions reductions of SO 2 and NO x fro m anthropogenic sources may be overw helm ed by seas onally variable OMC and CM, as well as EC and SOIL, extinction contributions due to em issions from natural sources.

These data suggest control of sources of OMC, CM, and SO 2 m a y be the most effective m eans of im proving visibility im pairm e nt at the Jarb idg e W ilderness Area. The following ch apter discusses Nevada’s sources of vi sib i lity im pairin g pollutants.

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-212.6 REFERENCES

U.S. EPA 2003. Guidance for Tracking Progre ss under the R e gional Haze Rule. EPA-454/B-03- 004. September 2003.

U.S. EPA 2003. Guidance for Estim ating Natu ral Visibility Conditions under the Regional Haze Rule. EPA-454/B-03-005. Septem ber 2003.

U.S. EPA 2007. Guidance for Setting Reasonabl e Progress G o als under the Regional Haze Rule. U.S. Environm ental Pro t ection Age n cy, Of f i ce of Air Quality and Stand a rds, Resea r ch Triang le Park, North Carolina. June 1, 2007 rev.

NEVADA REGIONAL HAZE S T ATE IMPLEMENTATI ON PLAN, October 2009 2-22