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Memorandum
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| U.S. Department of Transportation Federal Highway Administration |
| Subject: | INFORMATION: Project-Level Analysis of Air Toxic and PM2.5 Emissions |
Date: | February 4, 2002 |
| From: | James M. Shrouds Director, Office of Natural and Human Environment |
Reply to: | HEPN-10 |
| To: | Mr. John T. Price Division Administrator Carson City, NV |
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I am responding to your request for information regarding the analysis of air toxic and PM2.5 emissions in environmental documents. This concerns a letter dated January 7, 2002, to your office requesting a supplemental environmental impact statement (EIS) for the US-95 project in northwest Las Vegas. We have reviewed that letter and the attached reports.
The FHWA does recognize the uncertainties in dealing with emerging issues such as the impacts of air toxics and PM 2.5. Our office is in the process of conducting research in the area of mobile source air toxics (MSATs) and fine particulate matter. We are looking at short-term and long-term research strategies to address the high level of uncertainty in the current research. However, this research will take from several months, to several years to complete. In addition, U.S. EPA has described in their final rule on MSATs1 a Technical Analysis Plan through which they will continue to improve understanding of the risk posed by air toxics to public health and welfare. It will also allow them to evaluate the need for and appropriateness of additional mobile source air toxics controls for on-highway and nonroad sources, and their fuels. Based on the information developed through this technical analysis plan, they will conduct a future rulemaking, to be completed no later than July 1, 2004.
We did review the research available related to air toxics, including the "Multiple Air Toxics Exposure Study in the South Coast Air Basin (MATES-II)"2 . We also reviewed EPA's final rule on "Control of Emissions of Hazardous Air Pollutants From Mobile Sources"3 , an EPA Fact Sheet-National Air Toxics Program: Integrated Urban Strategy4, and Examples of Changes and Additions to the Final Urban Air Toxics Strategy5. We have also reviewed the information and technical studies that were provided with the January 7 letter. Based on this review, we have made the following conclusions:
Although U.S. EPA has established a list of MSATs, it has not established that emissions of these compounds are health risks, nor has it established any standard or measure of what concentration of these compounds might be harmful. U.S. EPA's final rule6 specifically states, "that inclusion on the list" of MSATs "is not itself a determination by EPA that emissions of the compound in fact present a risk to public health or welfare, or that it is appropriate to adopt controls to limit the emissions of such a compound from motor vehicles or their fuels."
Because of the complexity of assessing the health risks of any particular emissions compound, establishing a level of emissions or concentrations that constitute a health risk cannot be accomplished with one or two studies. In fact, the U.S. EPA in establishing standards for ozone and particulate matter to protect human health reviewed thousands7 of peer-reviewed scientific studies.
The MATES-II study found that concentrations of 1,3 butadiene, benzene, carbon tetrachloride, methylene chloride, perchloroethylene, trichloroethylene, hexavalent chromium, lead, and nickel had been reduced significantly between 1990 and 1999, and that these reductions in toxics exposure resulted in 44 to 63 percent reductions in carcinogenic risk to residents.
Time of exposure also influences health impacts. It should be recognized that the MATES-II study assessed "exposures as though individuals residing in the vicinity of a source remain in this location for a lifetime of 70 years. A different set of exposure assumptions may lead to lower exposure estimates and consequently lower risk estimates."8 This is important to recognize, especially in light of the fact that emissions of air toxics are predicted to be reduced substantially in the next 20 years.
In addition, it is unclear whether air toxics concentrations are of a regional nature, such as ozone, or have more localized impacts. The. U.S. EPA, the California Air Resources Board9, and the South Coast Air Quality Management District10 strategies to address mobile source air toxics have been directed to national and regional controls and programs. They have not been directed towards project-level mitigation. It is unclear the effect that individual transportation projects have in regard to air toxics.
The U.S. EPA has required a number of control strategies that the research shows has reduced mobile source air toxics in the past and will reduce air toxics into the foreseeable future. In fact, according to U.S. EPA's final rule11 on MSATs, between 1990 and 2020, on-highway emissions of benzene, formaldehyde, 1,3-butadiene, and acetaldehyde will be reduced by 67 to 76 percent, and on-highway diesel particulate matter emissions will be reduced by 90 percent. These reductions are due to the impacts of promulgated mobile source control programs, including the reformulated gasoline program, the national low emission vehicle standards, the Tier 2 motor vehicle emissions standards and gasoline sulfur control requirements, and the heavy-duty engine and vehicle standards and on-highway diesel fuel sulfur control requirements.
These air toxic reductions will be achieved even with growing vehicle miles traveled (VMT). Increased VMT in a future year does not equate with increased emissions compared to the current year. In fact, as seen above, the MATES-II study found that carcinogenic risk had been reduced in the South Coast area, even though at the same time VMT increased12. (From 1980 to 1999, VMT in the South Coast Air basin increased 81 percent.)
There is currently a lack of adequate analysis techniques to estimate and evaluate on-road mobile source air toxics. There is no microscale air toxics monitoring for the Las Vegas metropolitan area. In addition, there is no microscale analysis equivalent to the MATES-II Study. The MATES-II microscale air toxics study was meant to be a "pilot study" only within the South Coast Air Basin and it contains a statement that readers should avoid possible over-interpretation of the results.
FHWA does not believe that it is useful or appropriate to analyze air toxics impact at the project level at this time. The influence of this specific project could not currently be estimated in any meaningful way. Were it possible to generate credible estimates of whether emissions of these compounds increase or decrease, we still would not know whether these emission levels are likely to adversely impact health. In addition, there is a lack of monitoring or analysis techniques to validate any assessment. This would not help the NEPA decisionmaker or the public understand whether exposure to some level of emissions resulting from the project is harmful. And, as can be seen above, air toxic emissions are decreasing, and are predicted to continue to be reduced.
The January 7 letter also requested the preparation of a supplemental EIS to address the health effects of PM 2.5. The concerns expressed are that these health effects are not addressed within the context of the Transportation Conformity Rule (CFR Parts 51 and 93) and the National Environmental Policy Act.
The Transportation Conformity Rule requires that transportation plans, programs and projects conform to the purpose of the State implementation plan in air quality nonattainment and maintenance areas. As of yet, the U.S. EPA has not designated nonattainment areas for PM 2.5. Section 305 of the National Highway System Designation Act of 199513 specifically amended the Clean Air Act limiting the applicability of the transportation conformity provisions to nonattainment and maintenance areas. We believe that the Transportation Conformity Rule and court rulings are clear that the conformity requirements do not apply in areas that have not been designated as nonattainment areas for specific pollutants.
The U.S. EPA has determined the health effects of PM 2.5, and has set the PM 2.5 standard to ensure that the public health is protected. The FHWA does not have a role in terms of how health based standards are set for pollutants. Many areas of the country are in the process of monitoring levels of PM2.5, and this monitoring will serve as the basis for whether this pollutant needs to be addressed at the regional scale, local scale, or both. We believe the effect of PM2.5 at a project level cannot be determined at this time and it may be very similar to ozone in that it is a regional effect, not a localized effect.
We have reviewed your draft response to this letter, and redline/strikethrough comments are attached. We have coordinated this response with the Office of NEPA Facilitation. Based on the uncertainties with the existing and reasonably obtainable scientific information as summarized above, we believe a supplemental EIS addressing air toxics and PM2.5 will not provide a meaningful analysis for reevaluating the decisions made for this project. Therefore, with respect to these issues, we believe that the approved FEIS remains valid. We also believe this approach is consistent with CEQ regulations regarding the intent of NEPA documentation in the public decision-making process. To do otherwise would unreasonably hold ongoing projects hostage to the completion of major, multi-year national research and policy-making efforts. However, we will continue to coordinate with EPA on the issue of mobile air toxics and, as scientific research is further developed, examine the availability of information and the most appropriate manner to address the issue in a project analysis conducted under NEPA.
Attachment
1 "Control of Emissions of Hazardous Air Pollutants From Mobile Sources," Federal Register: March 29, 2001 (Volume 66, Number 61), page 17229, http://www.epa.gov/fedrgstr/EPA-AIR/2001/March/Day-29/a37.htm.
2 "Multiple Air Toxics Exposure Study (MATES-II)," South Coast Air Quality Management District (AQMD), March 2, 2000, http://www.aqmd.gov/matesiidf/matestoc.htm.
3 "Control of Emissions of Hazardous Air Pollutants From Mobile Sources," Federal Register: March 29, 2001 (Volume 66, Number 61), page 17229, http://www.epa.gov/fedrgstr/EPA-AIR/2001/March/Day-29/a37.htm.
4 "Fact Sheet-National Air Toxics Program: Integrated Urban Strategy," U.S. EPA, July 6, 1999 www.epa.gov/ttn/uatw/urban/urbanfs.html.
5 "Examples of Changes and Additions to the Final Urban Air Toxics Strategy," U.S. EPA, (www.epa.gov/ttn/uatw/urban/change7.html)
6 "Control of Emissions of Hazardous Air Pollutants From Mobile Sources," Federal Register: March 29, 2001 (Volume 66, Number 61), page 17229, http://www.epa.gov/fedrgstr/EPA-AIR/2001/March/Day-29/a37.htm.
7 "EPA's Revised Ozone Standard" Fact Sheet, U.S. EPA, July 17, 1997, http://www.epa.gov/ttn/oarpg/naaqsfin/o3fact.html, and "EPA's Revised Particulate Matter Standards" Fact Sheet, U.S. EPA, July 17, 1997, http://www.epa.gov/ttn/oarpg/naaqsfin/pmfact.html.
8 "Multiple Air Toxics Exposure Study (MATES-II)," Page 3-6, South Coast Air Quality Management District (AQMD), March 2, 2000, http://www.aqmd.gov/matesiidf/matestoc.htm.
9 Toxic Air Contaminant Control Program, California Air Resources Board, November 26, 2001, http://www.arb.ca.gov/toxics/control.htm.
10 "Final Draft Air Toxics Control Plan for the Next Ten Years," South Coast Air Quality Management District, March 2000, http://www.aqmd.gov/aqmp/atcp.html.
11 "Control of Emissions of Hazardous Air Pollutants From Mobile Sources," Federal Register: March 29, 2001 (Volume 66, Number 61), page 17229, http://www.epa.gov/fedrgstr/EPA-AIR/2001/March/Day-29/a37.htm.
12 "The 2001 California Almanac of Emissions and Air Quality," California Air Resource Board, April 12, 2001, Chapter 4, page 115, http://www.arb.ca.gov/aqd/almanac01/pdf/almanac2001%20all.pdf.
13 National Highway System Designation Act of 1995, Public Law 104-59, November 28, 1995, http://www.fhwa.dot.gov/legsregs/nhsdatoc.html.
