May 19, 2000

In response to your request to assess the adequacy of the air quality element presented in the Piedmont Triad International Airport Draft Environmental Impact Statement (DEIS), the following is provided.

Upon review of the project's technical documentation, numerous deficiencies were noted in the approach and assessment methodology utilized by the applicant. Of relevance is the applicant's failure to provide supporting documentation to validate the adequacy of the various operational profiles and emission inventory values presented in the DEIS. In addition, the applicant limits the assessment of air quality impacts to criteria pollutants and fails to address the generation and associated impact of toxic emissions commensurate with the projected increase in mobile source activity. As such, the applicant's analysis is flawed and provides little information to assess the project's potential to degrade local air quality and impact the health of those who live throughout the surrounding community.

The following is a discussion outlining the technical inadequacy of the project's environmental documentation.

In Chapter 5 of the DEIS, the applicant presents a discussion relating to the rationale and methodology for the emission inventory values associated with the "no-action" alternative and numerous project build-out scenarios. Although Air Quality Dynamics appreciates the applicant's attempt to provide the reader with an understanding of their assessment methodology, their discussion is interlaced with descriptive terminology such "generally consistent with " and "in general accordance with" regulatory guidance. However, without providing the reader with supporting documentation to validate such deviations or refinements to existing guidance, the applicant's assumptions and resulting values cannot be confirmed and are without merit.

To underscore our concern, the applicant provides a compilation of emissions for each project phase and alternative. Although these values were generated with a recognized model (i.e., Emissions and Dispersion Modeling System, Version 3.11), no documentation exists which

May 19, 2000

delineates the model's input and output values. In fact, in Appendix F which is identified as the source of "supporting" documentation for the air quality assessment, only aircraft type, engine, operational time lines and annual LTO's are reported. No emission inventory data is identified. As such, no examination of the applicant's assumptions and model assignments can be made to validate the emission inventory values presented in the DEIS.

Under the 1990 Clean Air Act, 188 compounds are identified as hazardous air pollutants. These compounds are classified as "hazardous" due to their potential to cause adverse health effects such as cancer. Additionally, the Clean Air Act required the U.S. Environmental Protection Agency (U.S. EPA) to control the emissions of hazardous air pollutants from major sources such as factories, refineries and mobile sources. As such, the U.S. EPA is charged with developing emission standards to prevent "an adverse environmental effect" or "provide an ample margin of safety to protect public health." For cancer risks, the margin of safety is defined as a lifetime cancer risk no greater than one in a million (1 x 10^-6 ).

Traditionally, air quality assessments associated with airport operations have been devoted to the quantification of six pollutants identified in the Clean Air Act. These criteria pollutants are nitrogen dioxide (N02), sulfur dioxide (S02), carbon monoxide (CO), ozone (03), Particulate matter (PM₁₀) and lead (Pb). Assessments for proposed Federal actions are required to determine compliance with the National Environmental Policy Act (NEPA) and general conformity requirements of the Clean Air Act. The quantification and assessment of toxic emissions generated from airport operations is, therefore, an exception rather than a requirement under existing Federal regulation. As such, approval to conduct an air toxic assessment and develop a methodology to perform the analysis must be made in conjunction with the appropriate Federal Aviation Administration (FAA) regional program office.

In addition to these Federal requirements, individual states may promulgate local requirements applicable to various airport operations. In North Carolina, however, the assessment of toxic emissions is not required for transportation facilities such as airports. Although the state reports that "(t)he problem of toxic compounds in the air has long been a concern of North Carolina", carbon monoxide is the only pollutant of concern identified in the Guidelines for Evaluating the Air Quality Impacts of Transportation Facilities promulgated by the North Carolina Department of Environment and Natural Resources (NCDENR).

Although Federal and state laws regulate the generation and subsequent risk associated with toxic air emissions from select stationary source operations, airports as a discrete "source" category are not expressly evaluated as a generator of toxic air emissions. Nevertheless, airports are arriong the largest single source emitters of pollutants due to an array of emission sources associated with their operation (i.e., aircraft, motor vehicles, ground support equipment and

May 19, 2000

stationary plant operations). However, existing regulations at the Federal and state level offer some control for limited stationary source categories (e.g., gasoline distribution facilities) should these operations relate to airport operations.

Nonetheless, it is by exception rather than rule that an air toxic assessment is prepared for an airport landing facility. It is relevant to note, however, that a health risk assessment conducted in 1993 for the U.S. EPA reported that aircraft engines are responsible for approximately 10.5 percent of the cancer cases within a defined geographic location (approximately 16 square miles) surrounding Chicago's Midway Airport. The authors of the report additionally note that "it is no surprise that emissions from aircraft engines may have a significant impact on the people living in the study area, especially to people living at receptors adjacent to the airport." The National Resources Defense Council (NRDC) commenting on the U.S. EPA assessment believes that "(t)he same conclusion might apply to people living immediately adjacent to airports all over the country."

Clearly, toxic emissions associated with the proposed project warrant consideration by the FAA and state authorities and must be addressed in the final Environmental Impact Statement report. To neglect the presence of toxic compounds generated from this source category would serve to underscore their limited concern for the health and welfare of those who live and work throughout the surrounding community .

Notwithstanding the applicant's failure to address the presence of toxic emissions and questionable accuracy of the emission estimates presented in the DEIS, Air Quality Dynamics utilized the published emission rate values for the W2-A Alternative to estimate the generation of toxic compounds for both Phase 1 and 2 scenarios. The following table presents the list of toxic compounds and corresponding source strength values associated with projected aircraft operations.

Note: Emissions are based on incremental values of predicted VOC emissions over the No-Action Alternative.

I have attached a worksheet which delineates the relevant aircraft inventory, LTO's, fleet mix and toxic emission profile utilized to generate the W2-A Alternative toxic emission inventory.

May 19, 2000

Please note that the above referenced values represent the contribution of aircraft emissions. On-road and non-road mobile sources are not included in the emission estimates. As known emitters of carcinogenic and non-carcinogenic compounds, their contribution must also be included in the quantification of emissions to identify the collective generation of toxic compounds associated with the proposed project. To underscore our concern and viability for this recommendation, the U.S. EPA reports that "mobile (car, truck, and bus) sources of air toxics account for as much as half of all cancers attributed to outdoor sources of air toxics."

Once the emission inventory is completed, the applicant must perform an appropriate health risk assessment to address the downwind extent of toxic compounds and their resulting impact on the health of those who reside within the neighboring community. Be advised that regulatory guidance is readily available to assist the applicant in conducting the risk assessment study and trust the community will attest to the applicant's obligation to perform this analysis.

I thank you for the opportunity to assist in your effort to ensure the full and open disclosure of environmental impacts associated with the Piedmont Triad International Airport project and look forward to evaluating the applicant's response to this memorandum. I can be reached at (3 10) 576-5837 should you have any questions or need additional information.

Sincerely,

Bill Piazza

:bp

Attachment: as stated

Piedmont Triad International Airport
Alternative W2-A (Phase 1)
(21 Tons/VOC)