1990 CLEAN AIR ACT AMENDMENT PROVISIONS PERTAINING TO AIR QUALITY MODELING INTRODUCTION The 1990 Clean Air Act Amendments (CAAA) contain a number of explicit provisions pertaining to air quality dispersion and/or photochemical modeling. Summaries of these provisions are presented by title and section number in the following paragraphs. These summaries provide a brief description of the role which air quality modeling plays in the implementation of the provisions contained within the CAAA. It should be noted that throughout the 1990 CAAA, there are many provisions which implicitly require the use of modeling in order to satisfy the requirements of those sections. For example, the sections contained in Title I which require States to submit revisions to State Implementation Plans for achieving the National Ambient Air Quality Standards (NAAQS) for ozone in moderate, severe, or extreme nonattainment areas do not specifically state that air quality modeling would be used as a part of an attainment demonstration. In reality, modeling would be an integral part of such demonstrations. Another example of such implicit requirements is found in Title III where modeling demonstrations will need to be used for determining carcinogenic and noncarcinogenic health effects to the general public from emissions of hazardous air pollutants and in assessing the effects from accidental releases of hazardous pollutants from various source categories. In addition, Title VIII mandates a cooperative study of the causes of visiblity degradation in southwestern New Mexico which has broad implications for modleing the impacts of a variety of sources on the regions visibility. These provisions of the CAAA which imply the use of air quality modeling as a means of implementing the requirements of these sections are not included in the summaries presented below. TITLE I - PROVISIONS FOR ATTAINMENT AND MAINTENANCE OF NATIONAL AMBIENT AIR QUALITY STANDARDS General Requirements for Implementation Plans Section 101(b) amends Section 110(a)(2)(K) by requiring that State Implementation Plan demonstrations provide for air qualtiy modeling to be performed as prescribed by EPA, with details of such modeling be provided to EPA upon request. Section 102(c) allows States, upon application to EPA, to use equivalent modeling procedures for the purpose of demonstrating reasonable further progress in nonattainment areas unless these techniques are proven to be less effective than the methods specified by EPA. Plan Submissions and Requirements Section 182(c)(2)(A) requires photochemical grid modeling (or other analytical methods approved by EPA) in order to demonstrate attainment of the ozone NAAQS in serious nonattainment areas by the applicable date. Grid models are also required for use in severe and extreme nonattainment areas. Revisions to applicable State Implementation Plans which incorporate these demonstrations must be submitted within 4 years of enactment of the CAA Amendments of 1990. Section 182(j)(1)(A) and (B) requires States in which there is located a multi-State ozone nonattainment area (i.e., where a portion of a single ozone nonattainment area covers more than one State), to include in the applicable implementation plan a demonstration using photochemical grid modeling (or other methods(s) approved by EPA) for achieving the NAAQS within the multi-State ozone nonattainment area by the applicable date. This includes moderate, serious, severe and extreme nonattainment areas. Control of Interstate Ozone Air Pollution Section 184(d) specifies that within 6 months of enactment of the 1990 CAAA the EPA is required to promulgate criteria for determining source contributions of ozone in one area to ozone concentrations in another area which is a nonattainment area for ozone. Such criteria shall require that the best available air quality monitoring and modeling techniques be used for purposes of making such determinations. NOx and VOC Study Section 185B requires EPA to conduct a study (with the National Academy of Sciences) on the role of ozone precursors in tropospheric ozone formation and control. The study objectives are to examine the roles of NOx and VOC reductions, the positive (or negative) contributions of NOx reductions to attainment of the ozone NAAQS, ozone sensitivity to NOx control, the availability and extent of controls for NOx, biogenic VOC emissions, and the basic information required for air quality modeling. The study is to be completed within 1 year of enactment of the 1990 CAAA (with a 30 day public review period) with a report submitted to Congress within 15 months of such enactment. Areas with Specific Stationary Source Emissions Section 187(c)(3) requires EPA to issue guidelines for determining whether stationary sources contribute significantly to carbon monoxide levels in an area. Modeling results will be used in any such determination. Plan Provisions and Schedules for Plan Submissions Section 189(a)(1)(B) requires States which contain all or part of a moderate area for PM-10, to submit with the applicable implementation plan (within 1 year of enactment of the 1990 CAAA), a demonstration (which includes air quality modeling) that the plan will provide for attainment of the NAAQS by the applicable date or that attainment by the applicable date is impracticable. Section 189(b)(1)(A) requires States which contain all or part of a serious area for PM-10, to submit with the applicable implementation plan (within 1 year of enactment of the 1990 CAAA), a demonstration (which includes air quality modeling) that the plan provides for attainment of the PM-10 NAAQS by the applicable date or, for areas for which the State is seeking an extension of the attainment date (pursuant to Section 188 (e)), that attainment by the applicable date is impracticable and that the plan provides for attainment by the most expeditious date practicable. TITLE II - PROVISIONS RELATED TO MOBILE SOURCES Fugitive Dust Section 234(a) requires EPA to review the accuracy of the Industrial Source Complex (ISC) Model and AP-42 emission factors for estimating fugitive emissions of PM-10 from surface Coal mines. Furthermore, EPA shall make the necessary revisions to ensure that any significant over-prediction of air quality concentrations does not occur from using such models. The EPA shall also allow States to use an alternative empirical based model as a means of estimating surface mine fugitive emissions until the EPA develops a revised model for such use. Any revisions to the ISC model must be completed no later than 3 years after enactment of the CAAA. TITLE III - HAZARDOUS AIR POLLUTANTS Area Source Program Section 112(k)(3) requires EPA (within 5 years of enactment of the CAAA) to develop a national strategy (with subsequent implementation to occur within 9 years of enactment of the CAAA) to reduce the public health risks associated with the release of hazardous air pollutants from area sources. This strategy must identify at least 30 hazardous pollutants which pose the greatest public health risks, must identify the top source categories or subcategories emitting such pollutants, must include a schedule of specific actions for reducing public health risks, and may identify research needs for air quality modeling along with other needs such as monitoring, analytical methods, and pollution control techniques. The EPA is required to include in this national strategy, emissions modeling and ambient monitoring in urban areas to demonstrate satisfactory completion of the goals and objectives of the strategy. State Programs Section 112(l)(3) requires the EPA to establish and maintain an air toxics clearinghouse to provide technical information and assistance to State and local agencies. Such a clearinghouse shall include information on control technology, health and ecological risk assessment, risk analysis, ambient air monitoring and modeling and emissions measurement and monitoring. Residual Risk Section 112(f) requires EPA to review all technology-based emission standards 8 years after promulgation and to promulgate health-based standards if such standards are necessary to protect public health with an ample margin of safety. Modeling will be required in determining if such health-based standards are necessary. Other Provisions Section 112(n)(3) allows the EPA to conduct studies of hazardous air pollutant emissions at publicly owned treatment works to characterize the types of pollutants emitted from such facilities, and any industrial, commercial, and residential contributions to such air pollutants discharges. In conducting such studies, the EPA may prescribe the use of air quality modeling as well as sampling and risk assessment methods. TITLE IV - ACID DEPOSITION CONTROL Title IV does not contain any requirements that explicitly pertain to air quality dispersion or photochemical modeling. TITLE V - PERMITS Title V does not contain any requirements that explicitly pertain to air quality dispersion or photochemical modeling. TITLE VI - STRATOSPHERIC OZONE PROTECTION Title VI does not contain any requirements that explicitly pertain to air quality dispersion or photochemical modeling. TITLE VII - PROVISIONS RELATED TO ENFORCEMENT Title VII does not contain any requirements that explicitly pertain to air quality dispersion or photochemical modeling. TITLE VIII - MISCELLANEOUS PROVISIONS Establishment of Program to Monitor and Improve Air Quality in Regions Along the Border Between the United States and Mexico. Section 815 requires the EPA to negotiate with representatives of Mexico to authorize an air quality improvement program to monitor and improve air quality in regions along the United States-Mexico border. The program must include an air quality monitoring component which is sufficient to support the use of a state-of-the-art mathematical air quality modeling analysis for the purpose of predicting emission reductions necessary to bring about attainment of the primary and secondary NAAQS in both the United States and Mexico. Visibility Section 816 adds a new Section 169B(a)(1) to Part C of Title I of the Clean Air Act requiring EPA to conduct research to identify and evaluate sources and source regions which contribute to both visibility impairment and clean air in Class I areas. Such research shall include the use of regional air quality models which have been adapted for assessing such air quality visibility impacts to these areas. TITLE IX - CLEAN AIR RESEARCH Air Pollutant Monitoring, Analysis, Modeling, and Inventory Research Section 901(b) amends Section 103 (c) through (f) of the Clean Air Act to require EPA to conduct an air pollutant monitoring, analysis, modeling and inventory research program. This research program is to include the development of improved modeling methods to increase the level of understanding of sources of ozone precursors, ozone formation, ozone transport, regional influences on urban ozone, regional ozone trends, and interactions of ozone with other pollutants. Ecosystem Research Section 901(b) amends Section 103(e) of the Clean Air Act to require EPA to conduct a research program to improve the understanding of the short-term and long-term causes, effects and trends of ecosystem damage from air pollutants. One of the required elements of this research is to improve current dispersion modeling techniques for evaluating and quantifying the exposure to and effects of multiple environmental stresses associated with air pollution. Liquified Gaseous Fuels Spill Test Facility Section 901(b) amends Section 103(f) of the Clean Air Act to require EPA to assist the Department of Energy and the Federal Coordinating Council for Science, Engineering, and Technology in a research program regarding the accidental release of liquefied gaseous fuels. The main purpose of this research is to develop improved predictive modeling methods for atmospheric dispersion by including such technical considerations as dense gas releases in complex terrains, the effects of turbulence on dispersion patterns, and the physicochemical reactions of aerosols with water vapor, ground deposition and removal by water spray. This research program shall also evaluate existing and future dispersion models by developing rigorous, standardized methodologies for dense gas models and apply such methodologies to existing dense gas dispersion models using field data. National Acid Precipitation Assessment Program Section 901(c) adds a paragraph (j) to Section 103 of the Clean Air Act establishing an Acid Precipitation Task Force under the acid precipitation research program as set forth in the Acid Precipitation Act of 1980. One of the responsibilities of such a task force is to coordinate air quality modeling research with other Federal agencies. This includes the maintenance, upgrading and applications of air quality models (e.g., Regional Acid Deposition Model) which describe atmospheric and ecosystem interactions with acid deposition. Western States Acid Deposition Research Sec. 901(g) requires EPA to conduct an acid deposition research program of the Western States to study the effects of acid deposition onto surface waters west of the Mississippi River. This research program shall use predictive air quality modeling to study the effectson acid deposition from projected increases in emissions of SO2 and NOx. TITLE X - DISADVANTAGED BUSINESS CONCERNS Title X does not contain any requirements that explicitly pertain to air quality dispersion or photochemical modeling. TITLE XI - CLEAN AIR ACT EMPLOYMENT TRANSITION ASSISTANCE Title XI does not contain any requirements that explicitly pertain to air quality dispersion or photochemical modeling.