California Regional Haze Plan

2014 Progress Report

ADOPTION DATE:

May 22, 2014
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Table of Contents

Section Page

Executive Summary.....................................................................................i

1. Background and Overview of Progress Report Requirements.........1

2. Control Strategy Status and Emissions .............................................6

3. Visibility Progress..............................................................................11

4. Assessment of Changes Impeding Visibility Progress ..................13

5. Assessment of Current Control Strategy ........................................18

6. Visibility Monitoring Strategy ...........................................................18

7. Regional Haze Plan Commitments and Continued Consultation ..18

8. Conclusion: Statement of Adequacy of Regional Haze Plan .........19

Appendix A: Western Regional Air Partnership:

“Regional Haze Rule Reasonable Progress Summary Report”

Appendix B: Emission Inventory

Appendix C: Supporting Deciview Record for California

Appendix D: Technical Analysis of Factors Impeding Progress

Appendix E: Federal Land Managers Review
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i

EXECUTIVE SUMMARY

The landscapes of California include some of the most beautiful and dramatic national 

parks, forests, wilderness areas, mountains, deserts, and seashores in the United 

States. Twenty-nine of these California locations were designated Class 1 Areas by 

those who manage them, to support national goals of improving visibility at these 

treasured public lands. California continues to reduce emissions of pollutants that result 

in regional haze, and visibility is improving at these unique places. State residents and 

visitors from all over the world have access to these special areas, making the shortand long-term goals of visibility improvement a worthwhile effort for everyone’s benefit.

There are many ways to measure visibility improvements; human visual perception is 

only one of them. Particles scatter and absorb light in the atmosphere, causing haze, 

which impairs the clarity of scenic vistas and views. The nationwide visibility monitoring 

program measures particles in the air as a way to track and compare variations in the 

amount of haze particles near the nation’s Class 1 Areas. Analyzing relative changes in 

concentrations of specific pollutant species over time helps identify potential sources, or 

causes of haze, at different times, seasons, and locations. These sources are both 

natural and man-made. The monitoring record in California now illustrates both short 

and long-term trends for most areas of the State. Overall, the record shows visibility 

has improved.

The California Regional Haze Plan addresses visibility goals and describes a strategy 

for controlling air pollution from man-made emission sources, including rigorous controls 

for stationary, area, and mobile sources. The State also supports initiatives to 

incentivize the development and use of innovative pollution control technology. The 

benefit of this concerted effort is more days of pristine air for viewing the magnificent 

landscapes of Class 1 Areas in California and in neighboring states. In fact, visibility at 

the Class 1 Areas in Southern California, nearest the most densely populated areas, 

has improved the most from emissions reductions.

This Progress Report examines the visibility data to show that reductions of precursor 

emissions are on track for meeting our visibility goals. California strategies for reducing 

oxides of nitrogen (NOx) have lowered nitrate particle concentrations and reduced haze 

levels throughout the State. Average visibility on the worst haze days is improving, 

although natural wildfire smoke continues to be the strongest driver of reduced visibility 

on worst days, at areas where progress is slower.

The California Regional Haze Plan control strategy is working to reduce emissions to 

reach short-term goals for 2018, as required. Reducing haze is a regional effort and 

California continues to work with the other western states and the federal land 

managers to plan for the required 2018 revision of State Implementations Plans for 

Regional Haze. The states are focusing on strategies for continued reduction of 

controllable emissions. Quantification of the impacts of wildfire smoke and other 

sources beyond State regulatory jurisdiction will continue, for the purposes of defining 

the burden these sources place on achieving visibility goals.
ii

The long-term trends for Worst Days averages show visibility improving at every 

monitoring site, in the absence of very high wildfire years. Current Best Days are all 

better or the same as those of the baseline period. As evidenced by reductions in 

anthropogenic source emissions in California and the concurrent improvement in 

visibility at all of California’s Class 1 Area IMPROVE monitors, California determines the 

current RH plan strategies are sufficient for California and its neighboring states to meet

their 2018 RPGs. In accordance with the requirements of the RHR, California has 

determined that no further substantive revision of the RH Plan is warranted at this time 

in order to achieve the 2018 RPGs for visibility improvement.
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1. Background and Overview of Progress Report Requirements

Congress recognized the importance of visibility in our national parks and wilderness 

areas by amending the Clean Air Act (Act) in 1977 to include a goal for “prevention of 

any future, and the remedying of any existing, impairment of visibility.”1

 In order to 

implement this provision of the Act, the U.S. Environmental Protection Agency 

(U.S. EPA) established the Regional Haze Rule (RHR)2 in 1999, specifying how states 

must work towards this visibility improvement goal. The RHR requires that states 

identify and implement pollution control strategies to make continuous progress towards 

a goal of “natural conditions”3 state of visibility by 2064.

Progress towards natural conditions visibility is expected by reducing or eliminating 

man-made impairment of visibility at the 156 Class 1 Areas in the United States. These 

public areas are national parks, forests, monuments, seashores, and wilderness areas 

managed by federal land management agencies. The RHR requires that continuous 

progress towards visibility improvement goals be evaluated at periodic checkpoints, with 

State Implementation Plans (SIPs) required every 10 years, and interim progress 

reports every five years.

The Air Resources Board (ARB or Board) adopted the California Regional Haze Plan 

(RH Plan) in January 2009 and transmitted it to U.S. EPA in March 2009. U.S. EPA 

approved the RH Plan in June 2011. The RH Plan described visibility conditions for the 

baseline years 2000-2004 and included the State strategy for reaching the first 

Reasonable Progress Goals (RPGs) in 2018. The 2018 RPGs are interim visibility 

improvement benchmarks on a path to the ultimate, long-term goal of natural 

background conditions. The 2018 RPGs were developed by ARB for each Class 1 Area 

in California, in consultation with other affected states and the federal land managers.

This first Progress Report (Report) evaluates progress made towards the 2018 RPGs 

and addresses the following:

• Status of RH Plan State strategy;

• Emissions reductions from RH Plan control strategies;

• Visibility progress;

• Emission trends;

• Assessment of changes impeding visibility progress;

• Assessment of current strategy;

• Review of visibility monitoring strategy;

• RH Plan adequacy determination; and

• Federal Land Manager comments.

 

1 Section 169A of the Clean Air Act. 2 CFR 40 Part 51 Regional Haze Regulations; Final Rule, July 1, 1999 

3 Note that “default” natural conditions as defined by the U.S. EPA are subject to revisions. States can 

extend the period of time needed to achieve natural conditions, beyond the nominal 2064 in the RHR, 

defining and defending new interim reasonable progress rates and adjusting the 2064 end year as 

needed (see CFR Section 51.308).
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1.1. California Class 1 Areas

California has 29 Class 1 Areas, more than any other state. Progress towards better 

visibility is calculated from data collected at the Interagency Monitoring of Protected 

Visual Environments (IMPROVE) network. There are 17 IMPROVE monitors 

representing one or more of the Class 1 Areas in California. Class 1 Areas in California 

with their respective IMPROVE monitor names and locations are shown in Figure 1.

Figure 1

Map of Class 1 Areas and IMPROVE monitors

IMPROVE monitor WA = Wilderness Area NP = National Park NM = National Monument
- 3 -

1.2. Measuring Visibility

Measuring visibility is complex. Particle and aerosol pollution in the air causes haze 

(light extinction) by extinguishing and absorbing light. The haze-causing particles and 

aerosols in the air are ammonium nitrates (nitrates), ammonium sulfates (sulfates), 

organic carbon matter aerosols (OMC), elemental carbon (EC), fine soil (FS), coarse 

mass (CM), and sea salt (SS). There is also natural light scattering by gases, Rayleigh

scattering, with a constant light extinction value based on elevation. Reducing the 

concentrations of the pollutant species means their contribution to light extinction 

lessens, and visibility improves.

The IMPROVE monitors measure the concentration of each haze-causing pollutant

every three days. Since each pollutant species has a different capacity to extinguish 

light, a mathematical formula was created to add up the light extinction caused by 

constant Rayleigh scattering and the different concentrations of pollutants on each 

measurement day. This formula, called the Haze Algorithm, converts the total light 

extinction calculated for each day into units of visibility called “deciviews”.4

 One 

deciview (dv) unit corresponds with the minimum visibility change detectable to the 

human eye. As deciview levels decrease, visibility improves.

The RHR requires that assessments of visibility progress must be based on five-year 

averages of the deciview values for the annual haziest (Worst) and clearest (Best) days

at each IMPROVE monitor. The Worst Days measurement is the average of the 

deciview levels for the 20 percent of the sampling days with the highest visibility 

impairment each year. The Best Days measurement is the annual average of the 

lowest 20 percent deciview days. 

The 2018 RPGs are the projected deciview levels for the Worst Days averages at each

monitor in 2018, after implementing the RH Plan’s State strategy. U.S. EPA approved 

the 2018 RPGs when they approved the RH Plan. Worst Days deciview levels should 

be decreasing as they progress towards the 2018 RPGs. The RHR also specifies that 

Best Days averages should not degrade from the baseline period (2000-2004).

1.3.Source Impacts on Visibility

A better understanding of visibility improvement emerges from relating reductions in 

precursor emissions in and near the Class 1 Areas to changes in concentrations of haze 

species measured at the monitors. Also important is the change in each haze species’

contribution to light extinction, as the mix of precursor emissions changes. Emissions 

from both natural sources and from man-made activities (anthropogenic sources) affect

visibility. These sources can be located within California, but long-range transport also 

brings visibility-impairing pollutants from out-of-State and international sources into 

 

4 Appendix A of the initial RH Plan explains further how deciviews are calculated from measurements of 

mass concentrations of haze species at each IMPROVE monitor.
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California’s atmosphere. California’s emissions control strategy focuses on sources 

within the State’s regulatory jurisdiction.

The fact that “uncontrollable” natural and anthropogenic sources affect visibility is not 

neglected in this analysis. For example, visibility progress in western states is slowed 

by the increased frequency and intensity in wildfires during the summer. Smoke 

originating from wildfires within and outside California generates enormous 

concentrations of organic carbon aerosols that form far-reaching plumes impacting 

many visibility monitors before dissipating. Depending on the wildfire location, smoke

impacts different monitors from year-to-year. Another annual event occurring beyond 

California’s borders are spring windstorms in the Gobi Desert, which have detectable 

but minor haze consequences in California at this time. Every year these seasonal 

windstorms send natural geologic material, coated with industrial emissions from Asia, 

into the jet stream which deposits dust at IMPROVE monitors in California and other 

western states.5

Uncontrollable emissions sources add to the atmospheric mix of visibility-impairing 

pollutants produced by anthropogenic sources in California, all detected but not 

differentiated by the IMPROVE monitors. Seasonal inversions, sea breezes, and 

humidity enhance the impact of these variable emissions. California’s coastal location,

complicated topography, and complex meteorology, may result in somewhat uneven 

year-to-year deciview progress at some sites, despite steady reductions of emissions. 

The Progress Report appendices describe localized and regional situations where 

uncontrollable emissions intensify the impacts on visibility progress.

1.4. Initial Reporting Requirements

In this first Progress Report, the RHR requires all states to report on the implementation

status for emission control measures implemented within the state for achieving 

reasonable progress towards the 2018 goals for Class I Areas within and outside the 

state. California’s first Progress Report is due to U.S. EPA in the Spring of 2014. In 

April 2013, U.S. EPA issued Guidance6 that states evaluate visibility improvement using 

the most recent monitoring data available for the initial Progress Reports. At the time of 

preparation of this Progress Report for the required review by the Federal Land 

Managers, the most recent monitoring data was available through 2011 at all but one of 

the seventeen IMPROVE monitors.7

 

5 VanCuren, R., and T. Cahill (2002), Asian aerosols in North America: Frequency and concentration of 

fine dust, J.Geophys. Res., 107(D24), 4804, doi:10.1029/2002JD002204. 6 “General Principles for the 5-Year Regional Haze Progress Reports for the Initial Regional Haze State 

Implementation Plans (Intended to Assist States and EPA Regional Offices in Development and Review 

of the Progress Reports)”, U.S. EPA, Office of Air Quality Planning Standards, April 2013. 7 The IMPROVE monitor SAGA, serving the San Gabriel Wilderness and the Cucamonga Wilderness, 

was destroyed in the summer wildfire called the Station Fire of 2009. SAGA was reestablished at the 

same location in the fall of 2011. Therefore data from the years 2005-2008 comprise the “current 

period” evaluated for SAGA in this Progress Report. The years 2009-2011 have incomplete deciview 

day data at SAGA so that Worst and Best Days annual deciview averages for those years do not exist.
- 5 -

In this Progress Report, “current” conditions are the five-year averages of 2007-2011 

visibility data, which is compared with “baseline” conditions, 2000-2004, from the initial 

California Regional Haze Plan. While some years may not have enough deciview days 

statistically to calculate the annual Worst and Best Days values, good information is still 

available for extensive parts of the year. Analyzing all the data gives a better 

understanding of seasonal patterns and long-term trends in visibility improvement.

For further analysis on a regional scale, California joined with fourteen other states to 

prepare the Western Regional Air Partnership (WRAP) Regional Summary Report 

included in Appendix A. The WRAP Summary Report was released in June 2013 and 

includes a comprehensive analysis of both measured visibility changes at the IMPROVE 

monitors and changes in emissions inventories between the baseline period and the five 

following years (2005-2009) to meet some of the RHR reporting requirements. 

California’s Progress Report goes further to update the Regional Summary Report with 

the 2007-2011 California-specific data.

The 2012 visibility data became available at the end of February 2014, during the 

Federal Land Managers review period. The timing of the data does not allow for an 

extensive analysis to be done in this Progress Report. However, the 2012 data is 

provided in Appendix C in summary format and mentioned in the Appendix D Case 

Studies. The 2012 summary data continues to illustrate progress in visibility 

improvement and does not change the conclusions of this Progress Report.
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2. Control Strategy Status and Emissions

In California, nitrate and organic carbon aerosols are the primary drivers of poor visibility 

on Worst Days. Sulfates can also play a role. Therefore, reductions in the precursors 

for these pollutants, NOx, ROG and SOx, along with directly-emitted PM2.5 support 

improvements in visibility throughout the State. In the RH Plan Control Strategy, 

California addressed all three precursors along with directly-emitted PM2.5. 

Mobile Sources are the primary contributor to NOx emissions, a precursor to nitrate. 

They also contribute SOx emissions, a precursor to sulfates; ROG emissions, a 

precursor to organic carbon aerosols; and PM2.5, a direct-emitter of organic carbon 

aerosols. Statewide control measures have been effective in driving all three of these 

types of emissions downward. Light-duty passenger vehicles, heavy-duty dieselpowered trucks, and off-road equipment were the three largest sub-category sources of 

all NOx emissions in 2000.

2.1. Status of Control Strategies in the RH Plan

The RH Plan Control Strategy relied upon already adopted ARB control measures for 

mobile sources and consumer products that reduce precursors of haze pollutants: NOx, 

SOx, ROG, and PM2.5. California’s aggressive and innovative control measures go 

beyond the federal requirements and defined a comprehensive and long-term basis for 

setting the 2018 RPGs. By regulating fuel and product formulations as well as mobile 

source equipment and pollution control technology, California’s control measures 

continue to provide significant emission reductions through 2018. Integrated programs 

addressing Diesel Risk Reduction, Goods Movement, and Smoke Management are 

designed to cover multiple source categories. California’s Smoke Management 

Program, certified by U.S. EPA in August 2003, continues to manage the occurrence of 

prescribed fires and smaller agricultural burns, by coordinating private, local, State, and 

federal actions. The Smoke Management Program requires that Class 1 Areas be 

identified as sensitive receptors. California also continues to supplement regulatory 

programs with financial incentives to accelerate early emission reductions and promote 

new technologies.

2.2. BART Requirement

In the RH Plan, Best Available Retrofit Technology (BART) was required for one source, 

the Main Stack at the Valero refinery in Benicia, California. The new control equipment 

was installed and operating by February 2011, prior to the 2013 compliance deadline. 

The BART determination concluded that the Main Stack and its contributing sources 

would be rebuilt to reduce emissions of SO2, NOx, and PM10. A fluidized coker, a 

fluidized catalytic cracker unit, and two CO boilers feed to the Main Stack.

The RH Plan BART determination described a technically feasible control system for the 

components that also produced a beneficial reduction in deciview levels modeled at the 

nearest Class 1 Area, Point Reyes National Seashore. A regenerative amine scrubber 
- 7 -

and a pre-scrubber were used for SO2 removal. The pre-scrubber also removes PM10. 

NOx is removed by selective catalytic reduction. Low NOx-burners are used for the CO 

boilers. With the installation of the improvements to the Main Stack as summarized in

the RH Plan, reductions of 0.65 tpd NOx, 15.7 tpd SOx, and 0.06 tpd PM10 were 

achieved.

Point Reyes National Seashore is the primary Class 1 Area affected by emissions from 

the Valero Refinery. Deciview and light extinction data from 2010 and 2011 are 

available for comparison prior to and after installation of the retrofit equipment. Figure 2 

shows the drop in light extinction, especially from nitrates and sulfates, at the PORE 

IMPROVE monitor. The corresponding deciview level for the Worst Days annual 

average went from 22 dv in 2010 to 20.2 dv in 2011. 

Figure 2

Comparison of Light Extinction at the PORE Monitor

2.3. New Control Strategies

In the RH Plan, California committed to give an update on new control strategies not 

included in the RH Plan. Due to the nonattainment challenges in California, ARB and 

local districts are regularly revising rules to account for new technologies. ARB 

research, coupled with incentives, provides the bridge to develop these new innovative 

technologies. The RH Plan reflected emissions from strategies adopted through 2004. 

Since the RH Plan was developed, ARB has adopted additional control measures. 

Table 1 includes a list of these control measures and appropriate implementation dates 

that were adopted by ARB and not reflected in the RH Plan Control Strategy. These 

control measures further reduced forecasted emissions in 2018 beyond what was in the 

RH Plan. Since these control measures were not used to set the 2018 RPGs, they will

provide additional emission reduction benefits to help California reach the 2018 RPGs.
- 8 -

Table 1

Control Strategies

Category Program Actions Implementation

Passenger Vehicles

Transit Bus Rule Additions 2005 2010

Zero Emission Bus Rule Amendments 2006 2010

Smog Check Improvements 2007-2009 2008-2010; 2013

Expanded Vehicle Retirement (AB 118) 2007 2009

Modifications to Reformulated Gasoline Program 2007 2010

Trucks

Heavy-Duty Sleeper Truck Idling Technology 2005 2010

Public and Utility Diesel Truck Fleet Rule 2005 2010

Border Truck Inspection Program Protocol 

Improvements 2006 2006

Cleaner In-Use Heavy-Duty Trucks 2007, 2008, 2010 2011-2015

Goods Movement Sources

Diesel Cargo Handling Equipment Rule 2005 2010

Ship Auxiliary Engine Cleaner Fuel Requirements 2005 2010

Auxiliary Ship Engine Cold Ironing & Other Clean 

Technologies 2007, 2008 2010

Cleaner Main Ship Engines and Fuel 2008-2011 2009-2015

Port Truck Modernization 2007,2008, 2010 2008-2020

Accelerated Introduction of Cleaner Line-Haul 

Locomotives 2008 2012

Clean Up Existing Harbor Craft 2007, 2010 2009-2018

Off-Road Equipment

Forklifts and Other Spark-Ignition Equipment 

Regulation 2006 2010

Off-Highway Recreational Vehicle Regulation 

Amendments 2006 2010

Cleaner In-Use Off-Road Equipment 2007, 2010 2009

Other Off-Road Sources

In-Use Diesel Agricultural Engine Requirements 2006 2012

Enhanced Vapor Recovery for Above-Ground 

Storage Tanks 2008 2009-2016

Additional Evaporative Emission Standards 2009 2010-2012

Areawide Sources

Portable Fuel Container Requirements 2005 2015

Consumer Product Lower Emission Limits 2006 2010

Consumer Products Program 2008-2011 2010, 2013-2014

In California, local air districts implement stationary source and indirect source control 

programs. This also includes the New Source Review and Prevention of Significant 

Deterioration permit programs. The Districts also utilize local and pass-through funds to 

incentivize reductions. Some local air districts encourage residential improvements that 
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reduce emissions, such as swap-outs, to battery-powered lawnmowers or to U.S. EPAcertified wood-pellet stoves. These programs have localized benefits for meeting the 

federal and State criteria pollutant standards. They also decrease emissions 

transported from populated areas to the more remote Class 1 Areas.

2.4. Emission Inventory

California’s control measures discussed above are reflected in the Statewide emission 

inventories shown in Table 2. This inventory is ARB’s latest inventory used for the 2013 

Almanac and is based on information developed for the daily PM2.5 standard SIPs

recently sent to U.S. EPA. The table includes both past and forecasted inventory years 

in five-year increments and includes years, 2000, 2005, 2010, 2015, and 2020. The 

ARB inventory is different from that of the WRAP Summary Report in Appendix A since

ARB has more recently updated the inventory to reflect revised emission factors and 

new assumptions for growth along with the units. ARB reflects the inventory in an 

annual tons per day unit which can be multiplied by 365 in order to get the WRAP tons 

per year unit. Appendix B includes additional information on the ARB emission 

inventory.

Table 2

California Statewide Inventory Summary (Tons Per Day)

POLLUTANT CATEGORY 2000 2005 2010 2015 2020

NOx STATIONARY SOURCES 584 402 313 288 291 

NOx AREAWIDE SOURCES 96 85 75 74 74 

NOx MOBILE SOURCES 3,103 2,727 1,935 1,525 1,188 

NOx GRAND TOTAL STATEWIDE 3,782 3,214 2,324 1,887 1,553 

ROG STATIONARY SOURCES 564 416 417 401 425 

ROG AREAWIDE SOURCES 783 713 655 611 630 

ROG MOBILE SOURCES 1,555 1,133 871 613 506 

ROG GRAND TOTAL STATEWIDE 2,902 2,261 1,943 1,624 1,561 

SOx STATIONARY SOURCES 132 97 64 54 55 

SOx AREAWIDE SOURCES 9 7 7 6 6 

SOx MOBILE SOURCES 148 182 52 18 21 

SOx GRAND TOTAL STATEWIDE 289 287 123 78 82 

PM2.5 STATIONARY SOURCES 92 91 82 65 69 

PM2.5 AREAWIDE SOURCES 445 309 275 277 281 

PM2.5 MOBILE SOURCES 123 124 90 68 64 

PM2.5 GRAND TOTAL STATEWIDE 661 524 447 410 414 

2013 Almanac

SOURCE: http://www.arb.ca.gov/aqd/almanac/almanac13/chap313.htm
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2.5. Control Measure Emission Reductions

California emissions have declined for all precursors since 2000 as shown in Figure 3. 

Between 2000 and 2020, mobile source NOx, ROG, and PM2.5 emissions are projected 

to be reduced by about 60, 65, and 50 percent, respectively. Stationary sources are 

also projected to decline for all precursors. Areawide sources also decline but not at the 

rate of mobile and stationary sources. Overall, between 2000 and 2020, NOx, ROG, 

SOx, and PM2.5 emissions decline almost 40 percent. These emission reductions 

reflect the maturity of California’s emission control program. 

Figure 3

California Statewide Inventory Trends

0

500

1000

1500

2000

2500

3000

3500

4000

2000 2005 2010 2015 2020

Tons Per Day

NOx

ROG

SOx

PM2.5
- 11 -

3. Visibility Progress

The RHR requires each state to assess visibility conditions and changes, using the 

Worst Days and Best Days metrics. The RHR requires states to assess current 

visibility, the change compared to baseline, and change over the past five years for both 

Worst Days and Best Days. For this initial Progress Report, the current conditions are 

the 2007-2011 period; the baseline period and past five years are the same, 2000-2004.

Table 3 compares Current and Baseline Worst Days and Best Days including the 

visibility changes as required by the RHR. Table 3 also compares Worst Days current 

conditions with the U.S. EPA approved 2018 RPG at each monitoring site, to show the 

percent progress achieved since the baseline, using the 2007-2011 five-year average. 

Visibility is improving on the Best Days at all monitoring sites meeting the RHR 

requirement that Best Days should not degrade. At nine monitoring sites, the current 

conditions already meet the 2018 RPGs. Visibility improvement at all but three of the 

monitoring sites indicates that by the end of 2011, progress exceeds 50 percent of that 

needed to reach the 2018 goals. Appendix C contains the Worst Day record since the 

baseline period. Looking at just 2011, all sites recorded values below the 2018 RPGs.

The three monitoring sites with the least progress, using the 2007-2011 five-year 

averages, are the LAVO, BLIS, and REDW IMPROVE monitors. Further analysis of 

trends in haze-causing pollutant concentrations and their contributions to light extinction 

at these three monitors reveals the cause of the limited progress. In the western U.S.,

wildfire smoke can elevate Worst Days values at particular monitors in a single year, as 

well as skew subsequent five-year averages. In 2008 and 2009, wildfire smoke caused

unusually high deciview Worst Day values with the first and third highest Worst Day 

value in 23 years of monitoring at the LAVO monitoring site. Wildfire smoke also 

impacted the BLIS monitoring site in 2007 and 2008 and caused the highest and 

second highest Worst Days annual averages in 16 years of deciview calculations at that 

location. In 2008, wildfire smoke also impacted the REDW monitoring site. As 

mentioned later, in Section 4, wildfire smoke can significantly impact visibility and mask 

improvements from emission controls. Appendix D examines the composition and 

timing of the Worst Day values in detail for these three monitoring sites.

Offshore emissions from ocean-going vessels (OGV) contribute to sulfate formation,

impacting visibility at monitoring sites closest to the coast. California has near-shore 

controls on OGV SOx emissions, however, sulfates are long-lasting once formed in the 

atmosphere. The coastal REDW, PINN, and RAFA monitoring sites may also be 

affected more by offshore sources, because they are located in remote areas with few 

other large SOx-emitting sources nearby. The current visibility at PINN and RAFA, 

while over 50 percent towards the 2018 RPG since the baseline period, are not 

improving as quickly as some of the other sites in California. No further analysis is 

included for RAFA and PINN because their current conditions years also include Worst 

Day values with high wildfire contributions in 2007 and 2008. In contrast, visibility 

improvement at PORE is progressing more quickly, because it is much closer to 

emissions reductions in a highly urbanized area.
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Table 3

Statewide 2018 Reasonable Progress Goal Summary

IMPROVE 

Monitor California Class I Area(s)

Best Days 

Baseline 

(dv)

Best Days 

(2007-2011) 

(dv)

Visibility 

Change 

(dv)

Worst Days 

Baseline (dv)

Worst Days 

(2007-2011) 

(dv)

Visibility 

Change 

(dv)

2018 

RPG

(dv)

Progress to 

2018 RPG

by 2011

NORTHERN CALIFORNIA

TRIN Marble Mountain W.

Yolla Bolly-Middle Eel W. 3.4 3.2 0.2 17.4 15.2 2.1 16.4 210%

LABE Lava Beds N.M.

South Warner W. 3.2 2.8 0.4 15.1 13.0 2.1 14.4 300%

LAVO

Lassen Volcanic N.P.

Caribou W.

Thousand Lakes W.

2.7 2.5 0.2 14.1 15.6 -1.5 13.3 -188%

SIERRA CALIFORNIA

BLIS Desolation W.

Mokelumne W. 2.5 2.2 0.3 12.6 13.0 -0.4 12.3 -133%

HOOV Hoover W. 1.4 1.3 0.1 12.9 11.5 1.4 12.5 350%

YOSE Yosemite N.P.

Emigrant W. 3.4 2.9 0.5 17.6 16.0 1.6 16.7 178%

KAIS

Ansel Adams W.

Kaiser W.

John Muir W.

2.3 1.6 0.2 15.5 14.9 0.6 14.9 100%

SEQU Sequoia N.P.

Kings Canyon N.P. 8.8 7.9 0.9 25.4 22.3 3.1 22.7 115%

DOME Dome Lands W. 5.1 5.1 0 19.4 18.3 1.1 18.1 85%

COASTAL CALIFORNIA

REDW Redwood N.P. 6.1 5.6 0.5 18.5 18.5 0 17.8 0%

PORE Point Reyes N.S. 10.5 9.1 1.4 22.8 21.6 1.2 21.3 80%

PINN Pinnacles W.

Ventana W. 8.9 8.0 0.9 18.5 17.5 1.0 16.7 56%

RAFA San Rafael W. 6.4 5.5 0.9 18.8 18.0 0.8 17.3 53%

SOUTHERN CALIFORNIA

SAGA San Gabriel W.

Cucamonga W. 4.8 4.5 0.3 19.9 18.0

(2005-2008) 1.9 17.4 76% by 

2008

SAGO San Gorgonio W.

San Jacinto W. 5.4 4.5 0.9 22.2 18.7 3.5 19.9 152%

AGTI Agua Tibia W. 9.6 7.4 2.2 23.5 19.8 3.7 21.6 195%

JOSH Joshua Tree N.P. 6.1 5.3 0.8 19.6 16.1 3.5 17.9 206%

W = Wilderness N.M. = National Monument N.P. = National Park N.S. = National Seashore
- 13 -

4. Assessment of Changes Impeding Visibility Progress

As discussed in the RH Plan, in California, there are three factors, largely beyond State 

control, that can interfere with progress towards improved visibility in Class 1 Areas: 

wildfire smoke, offshore shipping emissions, and Asian dust. These factors are either 

from natural sources (wildfire smoke), uncontrollable sources (shipping emissions

beyond California’s jurisdiction), or both (Asian dust, a combination of anthropogenic 

and natural sources beyond California’s control.)

Each factor can produce a spike in the sampling record measuring concentrations of

each haze species. Whether wildfire smoke originates in California or is transported 

from out of state, the signature appears as elevated organic carbon concentrations that 

can last for several consecutive sampling days or weeks, depending on the size of the 

fire.

Pacific offshore shipping emissions from vessels burning sulfur-containing fuels, have

increased dramatically in the last decade due to shifts in the global economy. These 

SOx emissions form sulfates, with higher levels near the California coastline, likely due 

to the higher humidity along the shoreline enhancing sulfate formation. Sulfates are 

normally elevated during the summer at all California monitors. They can be the 

secondary driver of haze at some monitors on Worst Days when elevated organic 

carbon is the primary driver. California has controlled both in-port and near-port 

shipping emissions with recently adopted measures. These controls have dampened 

the impact of shipping emissions, but cannot offset the changes beyond the State’s 

jurisdiction. The RH Plan estimated that more than 50 percent of the sulfate measured 

at the California coastal monitors was beyond the State’s control.

Asian dust, which has been identified by small amounts of marker soil elements at high

elevation IMPROVE monitors, has the most visible influence in the spring. At that time,

seasonal windstorms in the Asian deserts load the atmosphere with geologic dust. As 

these strong winds move across eastern Asia, the natural dust combines with, and is 

coated by, industrial pollution. These pollution-laden winds enter the jet stream 

crossing the Pacific Ocean and their plumes are visible in satellite photos. Asian dust is 

detected at the IMPROVE monitors as episodes of coarse mass and fine soils on single 

days, March through May, when these two haze species spike at the same time at 

many monitors in a region. Depending on other sources affecting a particular monitor, 

Asian dust events may elevate normal measurements sufficiently to cause occasional 

Worst Days in California. The WRAP Summary Report has more information about 

these regional transported dust episodes.

Wildfires are occurring more frequently. The largest wildfires in California, measured in 

acreage burned since 1950, occurred in the first decade of the 21st century. Figure 4

illustrates this increase.

8,9

 

8 http://oehha.ca.gov/multimedia/epic/pdf/ClimateChangeIndicatorsReport2013.pdf, p. 137. 9 http://frap.fire.ca.gov/assessment/assessment2010/document.html, 2010 graph.
- 14 -

Figure 4

Wildfire Acreage Burned in California

Wildfires cause organic carbon concentrations to increase significantly on days when 

wildfire smoke reaches a Class 1 Area, often remaining high for several consecutive 

days or even weeks. Organic carbon is the largest contribution to light extinction on 

those days, sometimes making the deciview level high enough to skew the annual 

Worst Days average. Further analysis of which haze species cause the Worst Days, 

and their timing, clearly implicates wildfire smoke as a challenge that impacts California 

on a regular basis.

In 2008, Northern, Sierra, and Coastal California were particularly affected by a large 

number of wildfires known collectively as the 2008 Lightning Strike Complex. Wildfire 

smoke began June 22 and did not die out until after the last ignition in August. Figure 5

shows the name, location, and size of these fires, many of which burned and smoldered 

beyond their containment date. This smoke directly impacted the Class 1 Areas and 

had an overwhelming impact on visibility progress at many monitoring sites throughout 

California and the west. 
- 15 -

Figure 5

The 2008 “Lightning Strike Complex”
- 16 -

The satellite image in Figure 6 shows the extent of smoke plumes during the summer of 

2008, almost three weeks after lightning strikes first ignited the dozens of wildfires 

throughout the State. The image shows how wildfire smoke can be transported far 

beyond its origin. The image also shows the wildfire smoke proximity to the REDW, 

BLIS, and LAVO monitoring sites. These were the only monitors in California, based on 

2007-2011 data, where current visibility progress was less than halfway towards 

reaching the 2018 RPGs. The technical analysis of long-term deciview trends, 

monitoring data not impacted by wildfires, and anthropogenic emissions, found in 

Appendix D, demonstrates that visibility is otherwise improving at these locations.

Figure 6

NASA Satellite Photo: July 9, 2008

● REDW

●LAVO

● BLIS
- 17 -

The California Department of Forestry and Fire Protection (CalFire) estimates that 

80 percent of the State is considered wildlands, with a range of fire frequency and 

severity as shown in Figure 7.

10 California’s Class 1 Areas are all susceptible to 

wildfires. Even Joshua Tree National Park, the only Class 1 Area partially within an 

area which infrequently burns, is directly downwind of smoke plumes from frequent and 

severe fires burning in the San Bernardino and San Jacinto Mountains. Depending on 

when and where they occur, wildfires will continue to be an impediment to reaching 

natural conditions in the future.

Figure 7

Wildfire Frequency and Intensity

 

10 California Department of Forestry and Fire Protection, Draft Vegetation Treatment Program 

Environmental Impact Report, October 30, 2012, Chapter 4 and Figure 4.2.1.
- 18 -

5. Assessment of Current Control Strategy

The RH Plan Control Strategy is sufficient for meeting California’s 2018 RPGs. The 

recent IMPROVE data year, 2011, shows that all sites for the year 2011 are below the 

2018 RPGs. In addition, California continues to strengthen existing control measures 

due to the severity of the air quality problem. California is currently developing SIPs for 

the 75 ppb 8-hour ozone standard and the 12 ug/m3 annual PM2.5 standard which are 

due in the 2016 timeframe. This provides strong evidence that California is on track to 

meeting the 2018 RPGs throughout the State.

The RH Plan control strategy is also sufficient to lessen California’s impact on 

neighboring states. In the RH Plan, California determined that the State contributed 

about three percent or less nitrate on Worst Days at Jarbridge Wilderness Area, 

Kalmiopsis Wilderness Area, Crater Lake National Park, Sycamore Canyon Wilderness 

Area, and Grand Canyon National Park. In the RH Plan, the NOx emissions were 

forecast to decrease about 40 percent in California by 2018. Now, California NOx 

emissions are decreasing by almost 60 percent between 2000 and 2020, exceeding 

what was in the RH Plan.

6. Visibility Monitoring Strategy

California will continue to rely on the IMPROVE network to collect and analyze the 

visibility data. During the current reporting period, the SAGA monitor was destroyed by 

the Station Fire in August of 2009. The site was re-established in October of 2011. The 

U.S. Forest Service (USFS) and their contractors were able to collect data and calculate 

light extinction for parts of 2009 and 2011. There was sufficient data for averaging four 

years, 2005-2008, used as the current reporting period for SAGA without data 

substitution. There are no current recommendations for changing the monitoring 

locations.

7. RH Plan Commitments and Continued Consultation

In the RH Plan, California committed to update the 2018 RPGs with the latest WRAP 

modeling if appropriate. Since submission of the RH Plan, WRAP has not updated the 

modeling for the California 2018 RPGs. California will continue to examine refinements 

to the Natural Conditions targets, given the increases in wildfires in California.

ARB staff regularly confers with other western states to discuss mutual concerns and 

strategies for reducing haze, through the WRAP and the Western States Air Resources 

Council (WESTAR.) ARB staff participated in the WESTAR Regional Haze 

Subcommittee, which developed recommendations regarding continued implementation 

of the Regional Haze Rule. These recommendations were presented to the U.S. EPA 

in August of 2013. ARB staff also consulted with the other western states, regarding 

whether anthropogenic sources or controllable activities in California affected the 

progress towards 2018 RPGs of these states. There is general agreement that smoke 

emissions from wildfires, especially in 2007, 2008, and 2009, did impact other States. 
- 19 -

In turn, smoke emissions from Oregon wildfires sometimes impacted California Class 1 

Area monitors. California has determined that absent these natural wildfire smoke 

impacts, visibility is improving sufficiently due to reduction of anthropogenic emissions, 

in-state and out-of-state.

ARB staff also meets routinely with the Federal Land Management Agencies (FLMs) 

with Class 1 Areas in California to review visibility progress, to share technical and 

research information, and to discuss policies leading to air quality improvement. This 

occurs at the staff level throughout the year at Interagency Air and Smoke Council

meetings and through senior management meetings of ARB, air districts, CalFire, and 

FLM representatives in the State at the Air and Land Managers meetings. California 

provided the draft Progress Report to the FLMs sixty days in advance of the public 

notice of the hearing on the Progress Report, for their review and comments. Appendix 

E includes their written comments and the responses from ARB staff.

8. Adequacy of Regional Haze Plan

California is making adequate progress overall in improving visibility due to reductions in 

emissions from RH Plan control strategy. The trends for Worst Days averages show 

visibility improving at every monitoring site, in the absence of very high wildfire years. 

Current Best Days are all better or the same as those of the baseline period. As 

evidenced by reductions in anthropogenic source emissions in California and the 

concurrent improvement in visibility at all of California’s Class 1 Area IMPROVE 

monitors, California determines the current RH plan strategies are sufficient for 

California and its neighboring states to meet their 2018 RPGs. In accordance with the 

requirements of the RHR, California has determined that no further substantive revision 

of the RH Plan is warranted at this time in order to achieve the 2018 RPGs for visibility 

improvement.
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