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Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio (1998)

Chapter: 6. Comparing the Committee's Recommendations with EPA's Research Plans

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Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×

6
COMPARING THE COMMITTEE'S RECOMMENDATIONS WITH EPA'S RESEARCH PLANS

To help ensure the adequacy of the scientific information used to establish NAAQS, EPA maintains active intramural and extramural research programs on ambient air quality and health. A major component of EPA's current air-pollution-related research program focuses on the health risks resulting from exposures to airborne particulate matter. The research funds being invested by EPA in particulate-matter exposure and health-effects research are by far the largest single commitment of public or private resources available to address key particulate-matter research questions related to protecting public health. Thus, the allocation of EPA's resources (intramural or extramural, alone or in leveraged partnerships) and the strategy by which they are invested will be important factors in determining whether the nation successfully addresses key particulate-matter research topics in a timely and effective manner. To that end, the present NRC committee has begun to assess the degree to which EPA's current overall research efforts and plans concur with or differ from the committee's recommendations for highest-priority research investments. In some important areas, it recommends the redirection of some of EPA's resources.

CURRENT EPA RESEARCH FUNDING

EPA's particulate-matter research budget for the 1998 federal fiscal

Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×

year is $49.6 million. During the past 2 months, the committee heard presentations and received background materials from EPA officials and scientists describing their overall plans for allocation of most of this budget. A categorized summary of the planned budget for Fiscal 1998, derived by the committee from EPA's materials, is presented in Table 6.1. Of the total EPA budget for particulate-matter research in 1998, approximately 50% is devoted to intramural research, 39% to extramural research; and the remaining 11% to interagency research activities.

The committee reviewed EPA's overall plans in comparison with the committee's source-concentration/indicator-exposure-dose-response framework presented in this report (Figure 3.1 in Chapter 3), and found that of the total available, more than half of EPA's particulate-matter research resources are directed at better understanding health responses, through mechanistic and long-term health-effects research. Nearly one-third of EPA's total particulate-matter research resources appear to be allocated toward efforts to identify the links between sources and ambient particulate-matter concentrations and to improve ambient monitoring. Only 4% of the intramural budget for particulate-matter research in EPA's laboratories is focused on better understanding of the relationship between actual personal exposure and the particulate-matter concentrations measured at outdoor, fixed-site monitors. This is a critical deficiency that requires immediate rectification. And by design, the agency is apparently not planning major research on dose-response questions until the year 2000.

COMPARING EPA'S RESEARCH ALLOCATIONS WITH THE COMMITTEE'S RECOMMENDED RESEARCH PORTFOLIO

After the committee developed its recommendations for a portfolio of highest-priority particulate-matter research investments (Chapters 4 and 5), it compared its recommended research investment priorities with EPA's current research-funding allocations and plans. The committee finds that all of the questions addressed in EPA's current research plans fit within the overall source-concentration/indicator-exposure-

Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×

TABLE 6.1 Estimated FY98 EPA Research Allocationsa

Category

Intramural (Laboratories)

Extramural (Grants, Centers, HEI)b

Interagency

Total

SOURCE

 

 

 

 

Emissions Characterization

$2.9 (13%)

$0.3 (2%)

$3.2 (7%)

Atmospheric

 

 

 

 

Chemistry/Modeling

$3.2 (14%)

$1.3 (7%)

$4.5 (10%)

CONCENTRATION

 

 

 

 

Monitoring

 

 

 

 

Methods/''Platforms"

$4.9 (22%)

$1.3 (7%)

$6.2 (14%)

EXPOSURE

 

 

 

 

Exposure Relationships

$0.8 (4%)

$4.0 (23%)

$4.8 (11%)

DOSE

 

 

 

 

Exposure-Dose-Response

RESPONSE

 

 

 

 

Acute Health Effectsc

$8.8 (40%)

$2.5 (14%)

$3.0

$14.3 (32%)

Long-Term Health Effects

$1.0 (5%)

$8.0 (46%)

$1.0

$10.0 (22%)

NEW TECHNIQUES

$0.5 (2%)

$1.0

$1.5 (3%)

TOTALS

$22.1 (100%)

$17.4 (100%)

$5.0

$44.5 (100%)

a In millions of dollars (Source: Letter from J. Vandenberg, EPA, to J. Samet, Feb. 15, 1998)

b Derived from relative estimates of allocations for centers

c Includes susceptibility ($7.4), mechanisms ($5.4), biologically important (or key) components ($1.5)

Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×

dose-response framework used by the committee. Given the short time (approximately 2 months) available for the committee's study and deliberations thus far in preparing this report, and the evolving nature of EPA's plans, the committee was not able to make precise determinations of all differences between its highest-priority research recommendations and EPA's particulate-matter research budget.

It is clear that many of EPA's particulate-matter research activities and plans are consistent with the committee's recommendations. However, several important overall differences in funding allocations and in timing of investments seemed apparent. The committee's recommended research portfolio differs from EPA's plans with respect to some priorities, cost allocations, timing of research investments, and, in some cases, the specific approaches to important questions.

RESEARCH TO ADDRESS THE COMMITTEE'S MOST-IMMEDIATE PRIORITIES

The committee has identified two critical areas that require immediate research attention and do not appear to be adequately addressed by EPA. Both are needed to inform near-term decisionmaking on the particulate-matter NAAQS and to provide a foundation for future health-effects and implementation-related research. These areas are:

  • Developing a better understanding of the relationship between actual personal exposures and the ambient concentrations of particulate matter measured at stationary outdoor monitors to assess the validity and meaning of epidemiological studies and to build the base for future epidemiological studies and particulate-matter control strategies.

  • Determining through controlled animal and human exposure experiments the most biologically important components or characteristics of particulate matter (e.g., particle size and chemical composition) to best target future source characterization, source-receptor model development, risk assessment, and implementation of any standard

Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×

in a cost-effective manner that targets control strategies at the most-important sources of the most-important particulate-matter constituents.

In contrast, EPA's 1998 allocation of resources appears to focus only about 4% of its intramural resources on investigating ambient-versuspersonal exposure relationships, and only about 3% of EPA's entire 1998 particulate-matter research budget appears to be focused on identifying the most hazardous components of the particulate-matter mixture. Merely measuring outdoor-air quality at stationary sites will be insufficient to help EPA meet the important goal of reducing the major gaps in knowledge about actual human exposures to biologically important components or characteristics of ambient particulate matter.

OTHER ELEMENTS OF EPA'S PARTICULATE-MATTER RESEARCH PROGRAM

The committee's recommendations also differ regarding three longer-range areas of EPA's program:

  • Source-Concentration: Nearly one-third of EPA's particulate-matter research budget for 1998 appears to be directed at characterization of source emissions, atmospheric chemistry and modeling, and the development of new monitoring techniques and more sophisticated monitoring platforms. All of those components will eventually be needed in EPA's particulate-matter research and regulatory program, and this committee has recommended a smaller immediate commitment of resources (approximately 14%) to develop improved methods for the activities. However, the committee recommends that the largest EPA investments in these areas be deferred until a few years from now, when an improved understanding of the biologically important components and characteristics of particulate matter will allow more productive and cost-effective investment in measuring the important particle components in source emissions and ambient air. If EPA chooses to continue with earlier substantial efforts in this area (presumably in addition to the committee's recommended research activities), such efforts should be mainly devoted to advancing technology for sampling

Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×

and chemical speciation, especially for organic compounds, and to quantifying the composition and sizes of particulate matter that people breathe in outdoor and indoor air. Given the extended timetable for NAAQS implementation and state implementation plan (SIP) development over the next 15 years (Table 1-1), a major research investment in these areas at the turn of the century should provide ample time to develop these implementation tools.

  • Exposure-Dose-Response: Although the committee believes that major investments in dose-response research will not be very useful until further information on toxicological mechanisms is available, it recommends that carefully designed efforts begin immediately to develop biologically based models for deposition and fate of particulate matter in the respiratory tract of human subjects, especially for susceptible subpopulations.

  • Health Response: The committee notes that EPA has apparently proposed to make an appropriately large allocation of funds to research on health effects of exposure to particulate matter—more than 50% of the total particulate-matter research budget. However, the area of biologically important particulate-matter components and characteristics appears to be significantly underfunded, and the area of long-term effects, which is important and merits sustained investment over the longer term, is given too large an immediate allocation by EPA. The committee's second report, expected in December 1998, will investigate in greater detail the current EPA efforts and plans, and, if appropriate, will recommend more specific redirection in these important areas.

THE RELATIONSHIP OF RESEARCH TO MONITORING

Independent of the research program, EPA's air regulatory office is initiating an extensive PM2.5 NAAQS-attainment monitoring program to obtain data on PM2.5 levels across the United States. The committee considered EPA's plans for this regulatory-office program and for the allocation of research resources to the development of new monitoring techniques (including new, more-sophisticated monitoring platforms). The committee recognizes that substantial resources must be applied

Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×

to ambient monitoring to ascertain attainment of the standards in various geographic areas, but it is concerned that the monitoring program is moving forward rapidly with too narrow a focus on PM2.5. The committee is concerned about the scientific value of the data to be collected in these efforts if such monitoring is fully planned and implemented before some of the immediate research priorities are addressed and data gaps are filled. Moreover, as a secondary but critical goal, such a monitoring program should also be designed to support relevant health-effects, exposure, and atmospheric-modeling research efforts, or else the costs of some important research will increase greatly because of the need for additional monitoring.

EPA cannot assume that the implementation of the national PM2.5 monitoring network will provide useful data for improving research or risk assessments for particulate matter. Current plans (e.g., speciation of particulate matter at least every sixth day) are inadequate for this purpose. EPA's monitoring plans will undoubtedly provide substantial amounts of data useful for determining attainment of new PM2.5 standards in various locations. However, these data will only be useful in research if monitoring-system design and site location lead to population-exposure measures of sufficient biological relevance and accuracy. Without this, the State Implementation Plans may miss important targets for control.

Based upon theoretical considerations, the Federal Reference Method (FRM) sampler to be used by EPA is expected to lose volatile material (e.g., some nitrates and organics) from particle samples in quantities that are likely to depend upon location and season. Ongoing experiments are attempting to quantify the extent of this loss, and some data showing the bias toward undersampling of organics and nitrates have been presented at several conferences during the past 12 months. If those losses turn out to be substantial, then using the FRM would amount to quantifying only a fraction of the outdoor concentration, and that fraction would vary geographically and seasonally. Alternative technologies that overcome some of these biases are available and could instead be adopted.

EPA's planned PM2.5 monitoring network appears to place great emphasis on site zones intended to represent the outdoor exposure of

Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×

large communities. Greater use of continuous (hourly) monitors would help determine the times of day and the exposures of people who are commuting, working, or exercising outdoors (Watson et al. 1998). Such monitoring would facilitate time-series epidemiological studies. More chemical characterization of particulate matter would help to enable testing of more specific indicators than PM2.5 mass alone.

The committee recommends that EPA re-evaluate its current plans for the PM2.5 monitoring program in light of this report. The committee recommends that EPA consider more fully the possibility that future research results might indicate that the expensive monitoring program is not measuring the most biologically important aspects of particulate matter.

The plans for this program (e.g., number and location of monitors and specific objectives and operating conditions) should be thoroughly and independently peer-reviewed at an early date, while the opportunity still exists for such review to influence the monitoring-network design and operation. Changes could then be made to increase the scientific utility of EPA's monitoring data, while still meeting the need for assessing regulatory attainment of particulate-matter standards at selected sites. Included in the EPA monitoring program are plans for several "super" monitoring sites where more extensive monitoring efforts will take place. At these sites, ambient-concentration data will be collected for gaseous pollutants, as well as for several size and chemical fractions of particulate matter. The costs of these monitoring efforts will be considerable, but their utility for health-effects studies has not been adequately considered to date. EPA has proposed to spend more funds on the PM2.5 monitoring network than on all particulate-matter research activities combined next year (Fiscal 1999). Therefore, it is essential to leverage both regulatory monitoring and research efforts together to make the most effective use of resources to improve the scientific basis for decisionmaking.

OVERALL RECOMMENDATIONS

The committee reviewed EPA's overall planned research funding allocations for Fiscal 1998 and compared EPA's plans with the committee's

Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×

highest-priority research recommendations presented in Chapters 4 and 5. The committee concludes that many of EPA's particulate-matter research activities and plans are consistent with the committee's recommendations. However, the current EPA allocations and plans for research funding, although generally addressing aspects of particulate-matter pollution that are important and warrant study, should be redirected in some areas to focus on the most immediately critical research questions. Specifically, the committee recommends that:

  1. EPA should allocate its particulate-matter research funding priorities in accordance with the recommendations in this report, incorporating intramural, extramural, and interagency investment to implement the committee's portfolio, as well as tasks that the agency needs to accomplish in support of the regulatory program and to complete worthwhile studies already in progress. The committee expects its next (December 1998) report to examine EPA's particulate-matter research plans and approaches in greater detail and to offer more specific suggestions for investment of these funds.

  2. This may require that EPA consider redirecting some of the funds planned for immediate work on source characterization and modeling by the agency's intramural laboratories and applying them instead to increased intramural research on the relationships between ambient monitoring results and actual personal exposures, particularly for potentially susceptible subpopulations. If the current mixture of expertise in EPA's intramural laboratories does not permit that change to be made expeditiously, then additional resources must be applied to support extramural research on the committee's recommended questions (although EPA also needs to build more inhouse capability in this area). At the same time, it is appropriate for EPA to continue to invest some funds in the development of tools for enhanced source characterization, atmospheric chemistry, and modeling.

  3. EPA should reassess its current allocation of funds for research on toxicological mechanisms, susceptible populations, and long-term effects. This is necessary to ensure that more research is focused immediately on identifying the most biologically important components

Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×

and characteristics of the particulate-matter mixture and on identifying biological mechanisms that could link particulate matter more clearly to the health effects observed in the human population.

  1. EPA should redirect sufficient resources to undertake immediately carefully designed efforts to develop a biologically based dose model for deposition and fate of particulate matter in the respiratory tract in normal and compromised subjects.

  2. EPA should re-evaluate its current plans for the PM2.5 monitoring program in light of this report. The agency should consider more fully the possibility that future research results might indicate that the expensive monitoring program is not measuring the most biologically important aspects of particulate matter. Such an inconsistency could undermine the credibility and effectiveness of future control strategies and could underprotect susceptible subpopulations.

  3. EPA's currently planned, university-based centers of excellence for particulate-matter research will require time to develop before producing major results, so EPA should strive to initiate the competitive awards for more of these centers in Fiscal 1998 instead of Fiscal 1999, as currently planned. The centers should augment, not replace, specific investigator-initiated, competitive research grants or competitive cooperative agreements.

  4. In addressing each of these recommendations, EPA should seek a mixture of extramural and intramural investigations that takes maximum advantage of the contributions that extramural scientists can offer, while enhancing the intramural capacity of EPA to address key questions about particulate matter in a timely and credible manner.

Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×
Page 106
Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×
Page 107
Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×
Page 108
Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×
Page 109
Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×
Page 110
Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×
Page 111
Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×
Page 112
Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×
Page 113
Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×
Page 114
Suggested Citation:"6. Comparing the Committee's Recommendations with EPA's Research Plans." National Research Council. 1998. Research Priorities for Airborne Particulate Matter: I. Immediate Priorities and a Long-Range Research Portfolio. Washington, DC: The National Academies Press. doi: 10.17226/6131.
×
Page 115
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New National Ambient Air Quality Standards for airborne particles smaller than 2.5 micrometers, called PM2.5, were issued by the U.S. Environmental Protection Agency (EPA) amidst scientific uncertainty and controversy. In response to a request from Congress, Research Priorities for Airborne Particulate Matter, the first of four books in a series, offers a conceptual framework for an integrated national program of particulate-matter research, identifies the 10 most critical research needs linked to key policy-related scientific uncertainties, and describes the recommended timing and estimated costs of such research.

The committee concludes that EPA should devote more resources to investigating the relationships between fixed-site outdoor monitoring data and actual human breathing-zone exposures to ambient particulate matter and to identifying the most biologically important constituents and characteristics of particulate matter through toxicological studies. The recommended research activities are critical to determining actual exposures of human subpopulations most susceptible to harm from the most hazardous constituents of particulate matter. Future research will be an investment in public health and a means to ensure that resources spent on control technology and regulatory compliance will have a reasonable probability of success.

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