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Nashville 1999 Field Study Science Plan

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Nashville 1999 Field Study Science Plan NASHVILLE 1999 FIELD STUDY SCIENCE PLAN DRAFT October 1998 TABLE OF CONTENTS Introduction 1 Proposed Research 7 Primary PM and PM Precursor Emissions 11 PBL Dynamics 13 Ozone Production Efficiency 19 Characterization of Loss Processes 23 VOC Contribution to Ozone and PM Formation 27 Fine Particulate Matter Formation and Characterization 31 Nighttime Chemistry and Dynamics 37 Instrumented Aircraft 41 Ground-Based Measurements 61 Tracer Release 67 References 69 Appendix A Ð Southern Center for the Integrated Study of Secondary Air Pollutants (SCISSAP) A-1 Appendix B Ð The National Parks Service Enhanced Monitoring Network B-1 Appendix C Ð TVA/EPRI/NPS Enhanced Monitoring Site GSMNP C-1 Appendix D Ð SEARCH D-1 Nashville 99 Science Plan INTRODUCTION The SOS Paradigm and commercial organizations can manage the accumulation of ozone and other photochemical The oxidant-management approaches being used oxidants in the atmosphere, and decrease the during the 1980s were based largely on scientific injurious effects of these airborne chemicals in findings, air quality models, and related air quality various urban and rural areas. management tools from research conducted in southern California and the urban megalopolis in the northeastern United States. Few scientific studies had SOS Research been conducted in the South. In the late 1980s, however, studies began to emerge that pointed to the Prior to the late 1980Õs, biogenic hydrocarbons were SouthÕs unique air quality management problems. believed to play little or no role in ozone formation in These problems included: 1) a high frequency of air either the rural or urban atmospheres. Two papers mass stagnation, warm temperatures, high humidity, were pivotal in changing this viewpoint: 1) Trainer et and intense solar insulation that characterize the al., (Nature, 1987) showed that biogenic hydrocarbons regionÕs summer climate; 2) abundant natural played a major role in rural ozone episodes in the emissions of biogenic hydrocarbons from the SouthÕs eastern United States; and 2) Chameides et al., ample rural and urban forests; and 3) an (Science, 1988) showed that biogenic emissions anthropogenic emission mix dominated by island represented a significant source of volatile organic cities and rural point sources. Because of these compounds (VOCs) in Atlanta and that these unique characteristics, it became apparent that air emissions decreased the efficacy of a VOC-based quality management approaches developed in other ozone abatement strategy. The findings of Trainer et parts of the Nation might not be appropriate for the al. and Chameides et al. were a major driving force South. To address this concern, the Southern behind the inception of SOS and, consequently, the Oxidants Study (SOS) was formed in 1988. study of the role of biogenic VOC in ozone formation was identified as a prominent research theme for the The SOS is a coordinated, long-term research program program. focusing on the formation, accumulation, and management of photochemical oxidants in the South. Research conducted as part of the SOS program has Since its founding, the SOS has focused on two been broad in scope, necessitated by the complex general purposes: nature of the problem. The program participants have been responsible for significant advances in methods 1. Using the southern United States as a natural development, emissions characterization, model laboratory for policy-relevant scientific development and evaluation, and have provided investigations, improving scientific and public important new insights into the processes that control understanding of the chemical and meteorological ozone accumulation in the atmosphere (Fehsenfeld et processes that cause ozone and other al., 1993; Chameides and Cowling, 1995). photochemical oxidants to accumulate in the atmosphere near the ground; and Field programs conducted during the early years of SOS relied primarily on ground-based measurements 2. Evaluating alternative strategies by which leaders in the rural environment and were focused on in various Federal, State, municipal, industrial, developing a better understanding of the role of 1 Introduction biogenic emissions in ozone formation and exploring three-tiered (Level I, II, and III) network of ozone/NOY relationships. There were, however, two progressively more sophisticated surface chemistry SOS studies that used highly instrumented aircraft to stations was established. The 108 Level I surface provide a more comprehensive view of regional ozone monitoring stations, operated as part of various formation and transport. In each case, the regulatory and research networks, provided broad instrumentation mounted on the aircraft were used to spatial ozone coverage across the Nashville/Middle characterize the spatial variability of ozone and its Tennessee region and parts of eleven neighboring precursors over the region. Further, the flight paths states. Six Level II surface monitoring stations were designed to provide information on ozone provided continuous short-term (1 to 5 minute), high- formation in urban and power plant plumes. In 1990 sensitivity measurements of ozone (O3), sulfur dioxide an effort led by NOAAÕs Aeronomy Laboratory (SO2), nitric oxide (NO), total nitrogen oxides (NOY), (Trainer et al., 1995) made measurements around and carbon monoxide (CO) along with temperature, Birmingham Alabama while in 1992 the Tennessee relative humidity, wind speed, wind direction, and Valley Authority participated in a major field program solar radiation. Integrated, one-hour, pressurized in Atlanta Georgia (Imhoff et al., 1995) canister samples for VOC analysis were collected midday at each station. Two Level III stations, one The results of these studies demonstrated the extreme located approximately 20 km NE and the other value of the three dimensional information provided approximately 20 km SE of the Nashville urban center by these kinds of platforms. The experience obtained provided detailed research-grade photochemistry in the conduct of these studies and the analysis of the measurements (e.g., organic nitrates, peroxides, data collected provided critical new information on aldehydes, VOC speciation). A network of five wind ozone production efficiency in plumes and formed the profilers was also employed. basis for the Nashville/Middle Tennessee Ozone study that was conducted in 1994/1995. Six instrumented aircraft were employed during the study -- NOAA WP-3, DOE G-1, NOAA Twin Otter, TVA Bell 205, NOAA CASA 212, and NASA C-130. Nashville/Middle Tennessee Ozone Study Ð The first four of these aircraft made in-situ chemistry 1994/1995 and meteorology measurements and the last two had remote sensing capabilities. The SOS Nashville/Middle Tennessee Ozone Study was conducted in two phases. Phase I, a preparatory The six-week 1995 intensive study was structured study, was conducted during a three-week period in around a series of five aircraft-based experiments: the summer of 1994. During this period, four ground- based monitoring stations, two wind profilers, and two 1. Urban Plume - Measurements of ozone formation instrumented aircraft (the NOAA WP-3 and the TVA in the Nashville urban plume under free-flow and Bell-205 helicopter) were operational. This three- stagnation conditions. week period also provided opportunity for: 1) evaluation of protocols for the ground-based and 2. Power Plant Plume Studies - Measurement of aircraft-based measurements systems to be used in ozone destruction and production in fossil-fuel 1995; 2) accumulating baseline data to aid in planning fired power plant plumes. and calibrating instruments for the 1995 study; and 3) a rigorous intercomparison of the NOy measurement 3.Subregional Characterization - Detailed methods employed by various SOS groups in the 1992 atmospheric chemistry and meteorological SOS Atlanta Intensive and SOS-SERON field studies characterizations to evaluate urban-rural during 1992-1994. interchange and provide a detailed observational data set for model evaluations. Phase II was carried out over a six-week period (June 19-July 28) in 1995. During this second phase a 2 Nashville 99 Science Plan 4. Regional Characterization Ð Measurements using Inefficient ozone formation in plumes instrumented aircraft that extended north to the Cross-plume pollutant profiles obtained by the NOAA Great Lakes, south to the Gulf of Mexico, west to WP-3 were combined with detailed wind fields to Missouri and Arkansas, and east to the investigate O3 formation at various downwind Appalachian mountains to provide context for and distances for several pollutant sources with very contrast to the measurements in the different NOX emissions. The analysis of this data Nashville/Middle Tennessee area. from the measurements made in 1994 and 1995 indicate that NOX removal occurred rather quickly and 5.Aircraft Intercomparisons - Side-by-side that O3 production in these plumes was much less intercomparisons for the in-situ sampling aircraft efficient than ozone production from more dispersed and overflights for the remote-sensing aircraft NOX sources. supporting the quantitative assessment of data inter-comparability Reduced formation of H2O2 in plumes Peroxide concentrations were lower in urban and power plant plumes than in background air. The Findings From the 1994/1995 Study lower peroxide formation rates inside the plumes are thought to be a result of higher NOX concentrations The analysis of the measurements that were made that maximize radical consumption by NO2 to form during the course
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