Impact/Purpose:

The task objectives are to 1.) identify and develop the scientific information that is needed to identify and evaluate an accurate, efficient, and cost effective control strategy for anthropogenic VOCs based on their individual reactivities for ozone and PM formation; 2.) support the construction and testing of a new-generation smog chamber facility for studies of atmospheric chemistry and reactivity of consumer and commercial products (CCP) VOC emissions under low NOx conditions; and 3.) provide policy-related scientific support to EPA/OAR related to the implementation of an updated VOC reactivity policy.

Description:

This Task provides the scientific understanding, evidence and tools needed by the Agency and States to evaluate the feasibility of using a reactivity-based control strategy for VOCs, based on the potential ozone and PM formation characteristics of individual VOCs. The research directly addresses issues associated with implementation of Section 183(e) of the 1990 Clean Air Act, which requires the EPA Administrator to develop a reactivity-based strategy for control of consumer and commercial products (CCP) emissions. It has been established in response to Congressional concerns about the lack of credible scientific information in the reactivity area. This Task includes (1) smog chamber studies on the effects of VOC emissions on the production of ozone and PM in the atmosphere; (2) participation in the Reactivity Research Work Group (RRWG) to support joint government/industry partnership research programs on scientific issues related to development of reactivity-based ozone control strategies; (3) support to OAQPS on reactivity related issues; and (4) support for the biennial US-German workshop on ozone and PM policy issues, including VOC reactivity. The emphasis of the research performed under this task is develop robust, scientifically justifiable quantifications of the potential ozone formation caused by a wide variety of anthropogenic VOC emissions. These values will then be used to study the feasibility of regional and national control strategies based on this VOC-specific potential for ozone, and eventually PM2.5, formation.

Record Details:

Record Type:PROJECT

Start Date:10/01/2001

Completion Date:09/01/2003

Record ID: 56185

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Project Information:

Progress :The US Congress, interested in implementing Section 183(e) of the 1990 Clean Air Act, instructed EPA to fund development of a new generation smog chamber facility that would provide the credible scientific information needed for implementing Section 183(e). A four year cooperative agreement was established in 1999 between the EPA and UCR, as mandated by Congress, to build a new-generation smog chamber. Following the development of an optimum design, construction of the smog chamber facility has commenced in FY01, and initial tests on materials and measurement methods were begun in FY02.

To further respond to the Congressional concerns, EPA commenced an effort to review and update its reactivity policy, and developed a partnership-type collaboration of private industry, academia, and environmental groups. The national Reactivity Research Work Group (RRWG), consisting of representatives from Federal and State government agencies, private industry, environmental groups, and universities, was founded in 1998 (at EPA's initiative) to identify issues and associated research needs and promote sponsoring of research in the VOC reactivity area. This group has met quarterly since 1998, and EPA has continued to participate actively in FY02. A research plan has been developed by the RRWG, consisting of the highest priority/urgency research tasks in the reactivity area, and the working group has established a research program to address these. The largest research effort focuses on assessing the effects of large-scale reactivity-based substitutions on regional air quality using existing models, developing appropriate scenarios for general reactivity assessment, and developing model criteria for reactivity assessments. In FY02, EPA partnered with the California Air Resources Board and the American Chemistry Council to complete a trio of studies examining the spatial and temporal distribution of incremental reactivities and the effects of VOC controls.

Additional work has been performed to analyze smog chamber simulations to study relative reactivities and reexamine the ethane "bright line" exemption policy, and to update the CB4 mechanism which is used in the air quality models to study overall ozone formation.

Relevance : The scientific research and technical support covered under this task has a direct and immediate impact on an upcoming federal rule ("Recommended Policy on Control of Volatile Organic Compounds") potentially modifying the way that ozone-forming VOCs are regulated States. While ozone formation is the primary consideration of this rule, other characteristics such as toxicity and PM formation potential will also be a component of this rule. NERL is providing atmospheric chemistry expertise on this rule, and participating with numerous other offices within EPA, including OAR/OAQPS and ORD/OSP in the development of the rule. The work performed under this task will therefore serve the ultimate purpose of helping to develop more flexible, cost-effective, selective VOC control strategies for management of adverse ozone concentrations.

Congressional interest in this area is high. This research program was established in response to the 1998 Congressional hearings, and there have been three congressional inquiries on the status of this work since then. One result of these hearings was the designation of money to fund smog chamber construction with the University of California, as well as the establishment of an EPA component of research in this area. The measurements made in the new smog chamber, supported under this task, will provide critical scientific information to improve the treatment of atmospheric chemical processes in air quality models, especially in low-NOx atmospheres, such as those above rural areas and less polluted urban areas. The chemical mechanisms of such processes have been studied in past years but only for relatively high ambient NOx concentration conditions, such as those prevailing in heavily polluted urban areas. We now know that the chemistry under these high concentration conditions may be much different than that under lower conditions, because different reactions dominate depending on the magnitude of the VOC or NOx levels. Thus, it is important that chemical mechanism performance be tested under lower concentrations that are more representative of the ambient atmosphere, and that the mechanisms be further developed as needed to properly simulate these realistic conditions. The UCR cooperative agreement project aims to generate smog chamber evidence specifically on atmospheric reaction mechanisms and VOC reactivities for low NOx atmospheric reaction systems. This information is of direct value to all scientists - researchers and regulators - who use air quality models.

Clients :Helms, Wegmen (OAR/OAQPS), Keating OAR/OPAR), Fegley (ORD/OSP) Dennis, Arnold (ORD/NOAA), Tong (Region 9), US Congress

Project IDs:

ID Code :5980

Project type :OMIS