## CHAPTER 10 LOOKING BEYOND CURRENT REQUIREMENTS

Introduction Uncertainties Associated with the Technical Analysis A First Look at the Year 2020 Ozone Air Quality New Federal Air Quality Standards for Ozone and Fine Particulates New State PM Air Quality StandardsChapter 10 Looking Bey ond Current Requirements

10 - 1 

### INTRODUCTION

This Chapter presents additional analyses which are not requi red under law to be included in the AQMP, but are presented here for informational purposes because they have significant future implications to the re gion’s ability to reach clean air. Specifically this chapter discusses uncertain ties associated with the techni cal analysis provided in the AQMP; provides a first look at the year 2020; and lastly, offers a preliminary analysis regarding the new federal PM2.5 and 8-hour ozone ambient air quality standards.



### UNCERTAINTIES ASSOCIATED WITH THE TECHNICAL ANALYSIS

As with any plan update there are uncertaintie s associated with the technical analysis. The following paragraphs describe the primar y contributors to such uncertainties as well as some of the safeguards bu ild-in to the air quality planning process to manage and control such uncertainties.

Demographic and Growth Projections
Uncertainties exist in the demogr aphic and growth projections for the future base years. As projections are made to longer periods (i .e., over ten or more years), the uncertainty of the projections become gr eater. Examples of activities that may contribute to these types of uncertainties include th e rate and the type of new sources locating in the Basin and their geographic distribution, future year residential construction, military base reuse and their air quality impact , and economic prosperity.

Input Elements to Air Quality Models

In addition to the above, there are also uncertainties in the technical information gathered for the air quality analysis. There are three major input elements associated with any air quality modeling analysis : ambient air quality monitoring data; meteorological measurements; and emissions i nventory. All three input elements have various levels of uncertainties im pacting the technical analysis.

Ambient Air Quality Monitoring Data
Generally, ambient air quality m easurements are within plus or minus half of a unit of measurement (e.g., for ozone usually reported in units of pphm would be accurate to within ± 0.5 pphm). Due to this uncertainty, the Basin’s ozone attainment status based on ambient monitoring data would be achieve d if all ozone monitors reported ozone concentration levels less than or equal to 12.4 pphm.Final 2003 AQMP

10 - 2 Meteorological Measurements
Air Quality models have to rely on reliabl e meteorological input data to accurately simulate future ambient concentration levels . There are uncertain ties associated with meteorological measurements and model i nput parameters, such as averaging of instantaneous wind speeds and directions to hourly averaged valu es, and directional consistency during low (s tagnant) wind conditions.

Emissions Inventory
As discussed in Chapter 3, la rge uncertainties in the mobile source emissions inventory estimates have been observed as evident with the latest EMFAC2002 release. On-road mobile source emission estimates have increas ed with each new EMFAC release. Onroad mobile source emissions have inhere nt uncertainties also with the current methodologies used to estimate vehicle activ ity such as vehicle miles traveled. Stationary (or point) source emission estim ates have less associated uncertainties compared to area source emission estimates. Major stationary sources report emissions annually whereas area source emissions are, in general, estimated based on production or usage information. Area source emissions including paved road dust and fugitive dust have significant uncertainties in the estimati on of particulate (PM10) emissions due to the methodologies used for estimation, temporal loading and weather impacts.

Air Quality Models
The air quality models used for ozone and particulate air quality analysis are sophisticated, complex 3-dime nsional models that utilize 3-dimensional meteorological models, complex chemical mechanisms that accurately simulate ambient reactions of pollutants and sophisticated numerical me thods to solve complex mathematical equations that lead to the prediction of ambient air quality concentrations. There are uncertainties with the development of the mete orological data input to the 3-dimentional meteorological models, such as the estima tion of 3-dimensional wind fields from a limited number of meteorological measurem ents collected at various locations throughout the Basin. While air quality models progressively became more sophisticated in employing improved chemical reaction modules that more accurately simulate the complex ambient chemical reaction mechanisms of the various pollutants, such improved modules are still based on limited experimental data which carry associated uncertainties. In order to predict ambient ai r quality concentrations, air quality models rely on the application of sophisticated numerical methods to solve complex mathematical equations that govern the highly complex physical and chemical processes that also have associated uncertainties.Chapter 10 Looking Bey ond Current Requirements

10 - 3 Are There Any Safeguards Against Uncertainties?
Yes. While completely eliminating uncerta inties is an impossible task, there are a number of features and practi ces build-into the air quality pl anning process that manage and control such uncertainties and preserve the integrity of an air quality management plan.

It should be noted that uncertainties run in two directions and comparisons with recent year projections show that the air quality is improving at a greater rate than was projected. This would indicate that uncerta inties have not significantly affected the integrity of the Plan to date.

Furthermore, the concerns re garding uncertainties in the technical analysis are reduced with future AQMP revisions. Each AQMP revi sion employs the best available technical information available. Under state la w, the AQMP revision process is a dynamic process with revisions occurring every thr ee years. The AQMP revision represents a “snapshot in time” providing the progress ac hieved since the previous AQMP revision and efforts still needed in order to attain air quality standards.

Under the federal Clean Air Act, a state impl ementation plan (SIP) is prepared for each criteria pollutant. The SIP is not updated on a routine basis under the federal Clean Air Act. However, the federal Clean Air Act recognizes that uncertainties do exist and provides safeguards if a nonattainment area doe s not meet an applicable milestone or attain federal air quality standards by their a pplicable dates. Contingency (or backstop) measures are required in the AQMP and must be developed into regulations such that they will take effect if a nonattainment area does not meet an app licable milestone or attainment date. In addition, federal sa nctions may be imposed until an area meets applicable milestone targets.

In 1996, U.S. EPA released an updated guidance document on the use of modeled results to demonstrate attainment of th e federal ozone air quality standard 1 The guidance document recognized that there will be uncertainties with ozone modeling analysis. For severe and extreme ozone nonattainment areas , the U.S. EPA recommends that at least one “mid-course” review of air quality, emissions and mode led data be conducted. A second review, shortly before the attainme nt date, should be conducted also. Such actions will occur in the South Coas t Air Quality Management District.

1 U.S. EPA, Guidance on Use of Modeled Results to Demonstrate Attainment of the Ozone NAAQS, EPA454/B-95-007, June 1996Final 2003 AQMP

10 - 4 

### A FIRST LOOK AT THE YEAR 2020 OZONE AIR QUALITY

With continued growth in the South Coas t Air Basin beyond 2010, c oncerns have been raised whether the South Coast Air Basin can maintain the federal ozone air quality standard. As such, an ozone air quality an alysis for 2020 was perfo rmed. Data on the projected growth in the Basin and su rrounding areas were provided by SCAG.
The future year (2020) ozone air quality proj ections suggest that additional emissions reductions will be required to offset growth to maintain the 1-hour ozone standard and attain the 8-hour ozone sta ndard. Mobile source emi ssions projections through 2020 indicate that continued reductions in VOC and NOx will occur as newer vehiles are introduced. NOx reductions will be most significant between 2010 and 2020 with VOC reductions having a smaller role. Growth in the area source category will act to offset the mobile source VOC reduc tions by 2020 to reverse the trend of lowering ambient ozone concentrations.



### NEW FEDERAL AIR QUALITY STANDARDS FOR OZONE AND FINE PARTICULATES

In July 1997, U.S. EPA promulgated new national ambient air quality standards for ozone and particulate matter.

As part of the requirements of the CAA, every five years the U.S. EPA must review the ambient air quality standards and propose revisions, if necessary, to “protect public health with an adequate marg in of safety,” based on the la test, best-available science. This review process includes a comprehensive evaluation of the latest health studies; a redrafting, if appropriate, of the relevant pollutant criteria document; and a staff report recommending the position of the U.S. EPA sta ff relative to the air quality standards. Further, these documents and U.S. EPA staff recommendation are reviewed by a panel of independent experts authorized by th e CAA, the Clean Ai r Science Advisory Committee (CASAC).

In promulgating the new standards, U.S. EPA followed the elaborate review process described above, which took several years to complete. The evaluation of thousands of peer-reviewed scientific studies led to the conclusion that existing standards for the two pollutants, ozone and particul ates, were not adequately pr otective of public health and resulted in the promulgation of the new standards. The studies indicated that for ozone, longer exposures at levels below the exis ting 1-hour standard were found to cause significant health effects, including asthma a ttacks, breathing and respiratory problems, loss of lung function, and possible long-term lung damage and lowered immunity to disease. With respect to particulate ma tter, the studies indicated that exposure toChapter 10 Looking Bey ond Current Requirements

10 - 5 particles smaller than those that were bei ng regulated by U.S. EP A were found to lodge deeply in the lungs and cause premat ure deaths and respiratory problems.

On June 2, 2003, EPA published in the Fe deral Register its “Proposed Rule to Implement the 8-Hour Ozone National Ambient Air Quality Standard,” 68 Fed.Reg. 32801-32870. As part of that proposal, EPA solicits comme nt on a proposal to revoke the present 1-hour ozone standa rd either in whole or in part one year after EPA designates the 8-hour ozone nonattainment areas . (68 Fed.Reg. 32019.) It is expected that EPA will designate the 8-hour ozone nonattainment ar eas by April 15, 2004. (68 Fed.Reg. 32808.) EPA is extremely unlikely to finalize this rule before the 2003 AQMP is adopted and submitted to EPA. At present, it is uncertain whether, when, or to what extent EPA will revoke the existing 1-hour ozone standard. Therefore, the 2003 AQMP assumes the 1-hour ozone standard will remain in effect for the foreseeable future.



### What are the Health Concerns?

A brief summary of the effect s associated with these pollutant exposures at levels observable in Southern Califor nia is presented. A more detailed discussion of health effects is provided in Appendix I.

Ozone
People exercising outdoors, child ren and persons with preexi sting lung disease such as asthma are considered to be susceptible s ub-groups for ozone effects. Identified in human and/or animal studies with varying exposure duration the a dverse health effects which are either induced by ozone or associ ated with ambient ozone exposures include: breathing pattern changes; re duction in breathing capacity and exercise performance; increase in airway resistance ; susceptibility to infections; excess hospital admissions and emergency room visits; and acute inflammati on of the respiratory tract including some cellular changes.
The lowest range of ozone e xposure within which lung functional changes (decrease in breathing lung volumes and increase in airway resistance) are observed is 0.08 to 0.12 ppm for 6-8 hours under moderate exercisi ng conditions. Unde r similar exposure conditions, biochemical indicat ors of lung inflammation are induced in healthy adults exposed to ozone in the range of 0.08 to 0.10 ppm. Excess hospital admissions and emergency room visits are obs erved when hourly ozone conc entrations are as low as 0.08 to 0.10 ppm. Thus, the attainment of the current NAAQS (0.12 ppm) is not likely to prevent all the adverse effect s indicated from ozone exposure.Final 2003 AQMP

10 - 6 Particulate Matter
The major categories of adverse health effect s associated with PM10 include: increase in mortality associated with acute and chronic exposures; exacerbation of preexisting respiratory and cardiovascular diseases leadi ng to an increase in hospital admissions and emergency room visits; school absences; work loss days and restricted activity days; changes in lung function and structure; and altered lung defense mechanisms.
A review and statistical analysis of rece nt population studies pub lished on acute adverse effects of PM10 indicates that an in cremental increase of PM10 by 10 μg/m 3 can lead to a significant increase in both mortality and mo rbidity risks. The elderly, people with preexisting respiratory and/or cardiovascular disease(s) and children appear to be most susceptible to the effects of PM10. These findings suggest that even when an area meets the existing NAAQS for PM10 the community is likely to continue to have the adverse impact from ambient PM10 exposures.

A limited number of studies which have employed both PM10 and PM2.5 indices for pollution suggest that the adverse effects s how a better correlation with the latter. A growing consensus exists among the scientific community that the fine fraction of PM10 is relatively more toxic than the coarse frac tion and is responsible for the majority of PM10 effects observed.

In addition, U.S. EPA in its recent PM10 NAAQS review has concluded that the difference in exposure relations hips, and the strong likelihood of fine mode fraction of PM10 being significant contributors to PM -related health effects in sensitive populations, are sufficient to justify the consid eration of fine and coarse mode particles in PM10 as separate classes of polluta nts. Hence, U.S. EPA has recommended additional PM2.5 NAAQS.



### What is the New Federal Ozone Standard?

As a result of this review, U.S. EPA is phasing out and replaci ng the current 1-hour primary ozone standard with a new 8-hour standard to pr otect against longer exposure periods. (Areas currently exceeding the fe deral 1-hour standard are still commited to demonstrating attainment in accordance w ith their scheduled date). The new ozone standard is set at a concentration of 0. 08 parts per million (ppm) and represents a tightening of the existing 1-hour ozone standard which is set at 0.12 ppm. Under the form of the standard adopted by U.S. EPA, areas are allowed to disregard their three worst measurements every year and averag e their fourth highest measurements over three years to determine if they meet the standard.Chapter 10 Looking Bey ond Current Requirements

10 - 7 

### What are the new Federal PM Standards?

For particulate matter, U.S. EPA established a new annual and a 24-hour standard for the finest fraction of particulates , PM2.5 (particles less than 2.5 micrometers) to complement the existing PM10 standards. The new annua l PM2.5 standard is set at 15 micrograms per cubic meter and the new 24-hour PM2.5 standard is set at 65 micrograms per cubic meter. The annual component of the standa rd was set to provide protection against typical day-to-day exposur es as well as longer-term exposures, while the daily component protects against more extreme s hort-term events. For the new 24-hour PM2.5 standard, the form of the standard is based on the 98 th percentile of 24-hour PM2.5 concentrations measured in a year (averaged over three years) at the monitoring site with the highest measured values in an area. This form of the standard will reduce the impact of a single high exposure event that may be due to unusual mete orological conditions and thus provide a more stable basis for effective control programs.

While U.S. EPA has retained the current annual PM10 standard of 50 micrograms per cubic meter, it has modified the form of the 24-hour PM10 standard set at 150 micrograms per cubic meter. More specifi cally, U.S. EPA revised the 1-expectedexceedance form of the curre nt standard with a 99 th percentile form, averaged over three
years.


### Implementation of the New Federal Standards

Although the promulgation of the new standard s for ozone and fine particulates is complete, U.S. EPA has yet to promulgate the air quality designations of the various regions for the new ozone a nd PM2.5 standards. Under a consent decree that was reached in response to a laws uit that was filed by severa l environmental groups, U.S. EPA has agreed to finalize its designations fo r the 8-hour ozone sta ndard by 2004. In an effort to harmonize the implementation of both the 8-hour ozone a nd PM2.5 standards, the U.S. EPA will also attempt to complete its designations for the PM2.5 standard by the end of 2004.

The state implementation plans that will incor porate attainment dem onstrations with the new 8-hour and PM2.5 sta ndards are expected to be required within three years of the air quality designations or by 2007. Therefore, the current regulatory control strategies will continue to focus on attaining the 1-hour ozone standard with the recognition that these controls will have benefits toward attaini ng the 8-hour ozone and PM2.5 standards. The U.S. EPA is considering several options in transitioning from the 1-hour to the 8-hour standard, while ensuring that no backslidi ng will occur. Based on the recent consent decree guidance, it is most likely that the Basin will have to meet the federal PM2.5 standards by 2014 and the 8-hour ozone standard by 2021.Final 2003 AQMP

10 - 8 

### Assessment of the New Federal Standards

Ozone

The District has evaluated the differences between the current 1- hour standard and the new 8-hour standard for bot h 2001 (observed) and 2010 (pre dicted) ozone for this comparison. These differences are summari zed in Table 10-1. Currently, the 1-hour standards are exceeded by 58 percent. Th e maximum 8-hour would exceed the new standard by 80 percent. Future year projections show that the 1-hour standard would be met in 2010, but the maximum 8-hour standard would still be exceeded by 35 percent. Because federal guidance has not yet be en developed for modeling attainment demonstrations of a 4th highest value, a projection of the 4th highest 8-hour average ozone concentration cannot be made at this time.

TABLE 10-1 Comparison of Ozone Standards

Observed Max Value (ppm) % above

Std. Predicted Max Value (ppm) % above

Std. Predicted Max Value (ppm) % above

Std Option Standard (ppm)

2001 2010 Option-1 2010 Option-2 1-hour (maximum) 0.12 0.190 58 0.123 Met 0.124 Met

8-hour (maximum) 0.08 0.144 80 0.107 34 0.108 35

8-hour (4th highest) 0.08 0.139 74 * * * *

*Future-year federal guidance for atta inment demonstration not available.Chapter 10 Looking Bey ond Current Requirements

10 - 9 Particulate Matter
The annual average PM2.5 st andard is set at 15 μg/m 3 , and the 24-hour average PM2.5 standard is set at 65 μg/m 3

. A comparison of the current PM10 standard s and the new PM2.5 standards for 2001 and 2006 are shown in Table 10-2. The 2001 valu es are derived from the measurements sampled through the routine Basin PM10 air monitoring. The 2006 PM 2.5 values are estimated from the particulate modeling a pplications (discussed in Chapter 5 and Appendix V). Currently, the 24-hour average PM 10 standard is exceed ed by 46 percent. This maximum exceedance oc curred under high-wind "Santa Ana" conditions. The annual standard is exceeded by 26 percent. Attainment for both PM10 standards can be demonstrated by 2006.
For the new 24-hour average and annual sta ndards, PM2.5 in 2001 will be exceeded by 51 and 107 percent respectively. In 2006 the 24-hour averag e PM2.5 standard would be exceeded by 49 percent and the annual average st andard would be exceeded 95 percent. For the 2010 Option-1 control strategy, the 24-hour average PM2.5 standard would be exceeded by 5 percent and the annual average PM2.5 is estimated to be exceeded by 80 percent. The annual average PM2.5 for the Op tion-2 is expected to be approximately 81 percent above the federal standard and th e 24-hour average PM2.5 standard would be exceeded by 9 percent. For both control s cenarios, the 2010 PM10 federal standard is expected to be met.
It is also important in looking into the futu re to understand the significant components of PM2.5 as projected for the year 2006. Thes e are shown in Figure 10-1. The ammonium and nitrate portions represent the dominan t fraction of PM2.5 on both an annual and episodic (24-hour) basis. Note, too, that th e crustal component, as identified within the category labeled “others,” and which represen ts a significant fraction of PM10, plays a very small role in the PM2.5 picture. For the 24-hour standard , it is evident that significant reductions in ammonium nitrate will be needed over a nd above the current PM10 control strategy in order to attain a possible PM2.5 standard. Appreciable reductions will also be needed for both orga nic and elemental carbon, the former from VOC emissions and the latter from soot emissions, primarily from diesel exhaust.Final 2003 AQMP

10 - 10 TABLE 10-2 Comparison of Particulate Matter Standard

Observed Max Value (μg/m 3 ) % above

Std. Predicted Max Value (μg/m 3 ) % above

Std Predicted Max Value (μg/m 3 ) % above

Std Predicted Max Value (μg/m 3 ) % above

Std Option Standard (μg/m 3 )

2001 2006 2010 Option-1 2010 Option-2

Current PM 10 (24-hour) 150 219* 46 150 Met 133 Met 137 Met

Current PM 10 (Annual) 50 63 26 49 Met 45 Met 46 Met

New PM 2.5 (24-hour) 65 98 51 97 49 68 5 71 9

New PM 2.5 (Annual) 15 31 107 29 95 27 80 27 81

* The 24-hour Basin maximum average of 219 (μg/m3) occurred unde r high wind conditions And reflect the contributions of fugitive wind blown dust.



### NEW STATE PM AIR QUALITY STANDARDS

On June 2002, CARB also adopted new, stricter standards for particulate matter that would affect both the corse as well as fine partic ulate fraction. The ne wly adopted standards reduced the PM10 annual average standard from 30 microgram per cubic meter to 20 micrograms per cubic meter and retained th e 24-hour PM10 standard of 50 micrograms per cubic meter. The new PM2.5 annual average st andard was set at 12 micrograms per cubic meter. In addition, CARB also revised the monitoring methods for these standards, and delayed action on the proposed 24- hour PM2.5 standard in light of the recent findings related to statistical issues in several key short-te rm exposure health effects studies. Obviously, achieving these standards poses an even greate r challenge than meeting the new federal 8- hour ozone and PM2.5 standards.Chapter 10 Looking Bey ond Current Requirements

10 - 11 FIGURE 10-1
Estimated PM2.5 Components in 2006 (a) Predicted Annual Average (29 ug/m3)

10%

30%

13% 15% 8% 24%

SO4
NO3
NH4
OC
EC
Others

(b) Predicted Maximum 24-Hour Average (97 ug/m3)

5%

53% 17% 17% 8% 0%

SO4
NO3
NH4
OC
EC
Others