## INVESTIGATION OF ATMOSPHERIC OZONE IMPACTS OF 2,3,3,3-TETRA FLUOROPROPENE

Final Report to the

Honeywell International Inc

Contract UCR-09010016

By

William P. L. Carter

June 2, 2009

Center for Environmental Research and Technology College of Engineering University of California Riverside, California 92521ii 

### ABSTRACT

An experimental and modeling study was carried out to assess the impacts of 2,3,3,3- tetrafluoropropene on ground-level ozone formation compar ed to other chemicals that are emitted into the atmosphere. The experiments consis ted of incremental reactivity envi ronmental chamber experiments to determine the effect of adding the tetrafluoropropen e to irradiations of reactive organic gas (ROG) surrogate - NO x mixtures representing ambient conditions. Th e results were modeled using the SAPRC07 mechanism with the reactions of the tetrafl uoropropene added. The data were reasonably well simulated if it is assumed that nitrate formation from the reactions of peroxy radicals with NO was negligible. This mechanism was then used to calculate the atmospheric impact of the tetrafluoropropene in the box model scenarios to derive the Maxi mum Incremental Reactivity (MIR) and other ozone reactivity scales. 2,3,3,3-Tetrafluoropropene was calculat ed to have an ozone impact on a mass basis that is the same as that of ethane to within the va riability of the model for atmospheric conditions. The average ratio of mass-based incrementa l reactivities relative to ethane was 0.9 ± 0.2 and the MIR ratio was 1.0 ± 0.1. It is concluded that if ethane is used as th e standard to define “negligible” ozone impact for the purpose of determining VOC exemptions for ozone pr ecursors, then 2,3,3,3-tetrafluoropropene might meet this standard. 2,3,3,3-Tetrafluoropropene was also found to have no significant effect on particle formation in the incremental reactivity chamber experiments.iii 

### ACKNOWLEDGEMENTS AND DISCLAIMERS

This work was funded by Honeywell Interna tional Inc. through contract UCR-09010016. The environmental chamber experiments for this project were carried out at the College of Engineering Center for Environmental Research and Technology (CE-CERT ) primarily by Qi Li, Kurt Bumiller, and Quentin Malloy. Mr. Dennis Fitz also provided assistance in administering this project, and Ms. Kathy Cocker provided assistance in conducting the experiments and processing the data.

Although Honeywell International Inc. funded this work, the contents of this report reflect only the opinions and conclusions of the author. Mentio n of trade names and commercial products does not constitute endorsement or recommendation for use.iv 

### TABLE OF CONTENTS

INTRODUCTION ................................................................................................................... ..................... 1

EXPERIMENTAL METHODS........................................................................................................... ......... 2 Chamber Description............................................................................................................ .................. 2 Analytical Inst rumentation ..................................................................................................... ................ 4 Sampling methods ............................................................................................................... ................... 7 Characterization Methods....................................................................................................... ................ 7 Experimental Procedures........................................................................................................ ................ 8 Materials...................................................................................................................... ........................... 9

MECHANISM AND MOD ELING METHODS........................................................................................ 10 Base Mech anism................................................................................................................. .................. 10 Mechanism for 2,3,3,3-Tefralfuoropropene ....................................................................................... .. 11 Representation of Chamber Conditions........................................................................................... ..... 12 Atmospheric Reactivity Simulations............................................................................................. ....... 15

RESULTS AND DI SCUSSION ......................................................................................................... ........ 16 Characterization Results....................................................................................................... ................ 16 Incremental Reactivity and Mechanism Evaluation Results ................................................................ 20 Atmospheric Reactivity Calculation............................................................................................. ........ 25

CONCLUSIONS.................................................................................................................... ..................... 29

REFERENCES ..................................................................................................................... ...................... 31

APPENDIX A. BASE MECHANISM LISTING....................................................................................... 35v 

### LIST OF TABLES

Table 1. List of analytical and characterization instrumentation for the UCR EPA chamber................. 5

Table 2. List of model species added to the base mechanism to represent the atmospheric reactions of 2,3,3,3-tetrafluoroprop ene and its oxidation products........................................ 13

Table 3. List of reactions and rate constants used to represent the atmospheric reactions of 2,3,3,3-tetrafluoropropene and its oxidation products ........................................................... 14

Table 4. Summary of experiments carried out for this project.............................................................. 17

Table 5. Summary of initial concentrations and select ed gas-phase results of the incremental reactivity experiments. ........................................................................................................ ... 21

Table 6. Summary of conditions of scenarios used for reactivity assessment....................................... 26

Table 7. Calculated atmospheric incremental reac tivities for 2,3,3,3-tetrafluoropropene and ethane. ........................................................................................................................ ............ 28

Table A-1. List of model species used in the base SAPRC-07 mechanism, including the VOC species used in the chamber and atmo spheric reactivity simulations.. .................................. 35

Table A-2. Reactions and rate constants in the SAP RC-07 mechanism used in this work. See Carter (2009a) for documentation.......................................................................................... 39

Table A-3. Summary of photolysis rates used in chamber and ambient simulations............................... 55vi 

### LIST OF FIGURES

Figure 1. Schematic of the UCR EPA environmental chamber reactors and enclosure........................... 3 Figure 2. Spectrum of the light sources used in the UCR EPA chamber, with intensities normalized to give the same NO 2 photolysis rates................................................................... 3 Figure 3. Plots of best fit HONO offgasing parameters against UCR EPA run number. ....................... 19 Figure 4a. Experimental and calculated results of the incremental reactivity experiments with added 2,3,3,3-tetrafluoropropene. .......................................................................................... 22 Figure 5. Plots of reactivities of 2,3,3,3-tetrafluorop ropene relative to ethane against relative NO x levels for all the scenarios u sed for reactivity assessment. ............................................ 271 

### INTRODUCTION

Ozone in photochemical smog is formed from the gas-phase reactions of volatile organic compounds (VOCs) and oxides of nitrogen (NO x ) in sunlight, and control of both VOCs and NO x is required to attain air quality standards for ozone. Many different types of VOCs are emitted into the atmosphere, each reacting at different rates and havi ng different mechanisms for their reactions. Because of this, they can differ significantly in their eff ects on ozone formation, or their “reactivity”. In recognition of this, the U.S. EPA has exempted vol atile organic certain compounds with ozone impacts expected to be less than ethane from regulations as VOC ozone precursors (Dimitriades, 1999; RRWG, 1999a, EPA, 2005), and the California Air Resources Board (CARB) has adopt ed regulations with reactivity-based adjustments for sev eral types of VOC sources (CARB 1993, 2000) and is investigating their use for other sources (CARB, 2008).

Fluorinated propenes such as 2,3,3,3-tetrafluoropropene (CF 3 CF=CH 2 ) are compounds of interest to Honeywell Specialty Materials Company whose u se and manufacture may result in their being emitted into the atmosphere. This will result in these com pounds being subject to VOC regulations aimed at reducing ozone formation, which may adversely imp act their production costs and marketability. If these compounds can be shown to have ozone impacts less than or equal to ethane on a mass basis, a case might be made to the U.S. EPA to exempt them fro m regulations as VOC ozone precursors (EPA, 2005). Because of this, Honeywell contracted us to develop estimates of ozone impacts of these compounds in various ozone reactivity scales, and compare them w ith the ozone impacts for ethane (Carter, 2009a).

The results of our assessment indicated that 2,3, 3,3-tetrafluoropropene has about the same ozone impact as ethane on a mass basis (Carter, 2008). Ho wever, the ability of mechanisms to predict ozone impacts had not been experimentally verified for this compound, and an experimental study is required to support the use of these reactivity values in a pe tition to the EPA to exempt this compound from regulations on the basis of relatively low reactivity for ozone formation.

In view of this, Honeywell Corporation fund ed the College of Engineering, Center for Environmental Research and Technology (CE-CERT) at the University of California at Riverside (UCR) to carry out a project to reduce uncertainties in estim ates of the atmospheric ozone impacts of 2,3,3,3- tetrafluoropropene. This included conducting enviro nmental chamber experiments suitable for testing mechanisms for the gas-phase atmosphe ric reactions of this compound that affect ozone formation, using the results to evaluate the mechanism previously derived for this compound, revising or adjusting the mechanism to simulate the data, and recalculating its atmospheric impacts if the mechanism is revised. The approach used is similar to that used many ot her VOCs that have been studied previously (Carter, 2009a, and references therein), including the fluorinated propene trans 1,3,3,3-te trafluoropropene that was studied previously for Honeywell (Carter, 2009b). Th e methods, results, and conclusions of this project are documented in this report.2 

### EXPERIMENTAL METHODS

Chamber Description

All of the environmental chamber experiments fo r this project were carried out using the UCR EPA environmental chamber at CE-CERT. This is the same as the chamber used in our recently completed study of trans 1,3,3,3-tetrafluoropropene (Carter, 2009b). This chamber was constructed under EPA funding to address the needs for an improved environmental chamber database for mechanism evaluation (Carter et al, 1999, Carter, 2002). The objec tives, design, construction, and results of the initial evaluation of this chamber facility are described in more detail elsewhere (Carter et al, 1999, Carter, 2002; Carter, 2004, Carter et al, 2005a). A brief d escription of the chamber is also given below.

The UCR EPA chamber consists of two ~85,000-lit er Teflon® reactors located inside a 16,000 cubic ft temperature-controlled “clean room” that is continuously flushed with purified air. The clean room design is employed in order to minimize background contaminants into the reactor due to permeation or leaks. Two alternative light sources can be used. The first consists of a 200 KW argon arc lamp with specially designed UV filters that give a UV and visible spectrum similar to sunlight. Banks of blacklights are also present to serve as an alternative lower cost light source when blacklight irradiation is sufficient. Blacklights have a good representation of sunlight in the UV portion of the spectrum that affects most photolysis reactions of interest, and their use is sufficient for test compounds whose mechanisms involve do not involve photoreactive compounds, or only photoreactive compounds with known action spectra (Carter et al, 1995b). Since this is the case for the fluoropropenes studied here and by Carter (2009b), they were used for all experiments for this project. The interior of the enclosure is covered with reflective aluminum pane ls in order to maximize the availa ble light intensity and to attain sufficient light uniformity, which is estimated to be ± 10% or better in the portion of the enclosure where the reactors are located (Carter, 2002). A diagram of th e enclosure and reactors is shown in Figure 1, and spectra of the light sources are shown in Figure 2.

The dual reactors are constructed of flexible 2 m il Teflon® film, which is the same material used in the other UCR Teflon chambers used for mechan ism evaluation (e.g., Carter et al, 1995a; Carter, 2000a, and references therein). A semi-flexible frame work design was develope d to minimize leakage and simplify the management of large volume reactors. The Teflon film is heat-sealed into separate sheets for the top, bottom, and sides (the la tter sealed into a cylindrical shape) th at are held together and in place using bottom frames attached to the floor and moveable top frames. The moveable top frame is held to the ceiling by cables that are controlled by motors that raise the top to allow the reactors to expand when filled or lower the top to allow the volume to contr act when the reactors are being emptied or flushed. These motors in turn are controlled by pressure sensor s that raise or lower the reactors as needed to maintain slight positive pressure. During experiments the top frames are slowly lowered to maintain continuous positive pressure as the re actor volumes decrease due to sampli ng or leaks. The experiment is terminated once the volume of one of the reactor r eaches about 1/3 the maximum value, where the time this took varied depending on the amount of leaks in the reactor, but was greater than the duration of most of the experiments discussed in this report. Since at least some leaks are unavoidable in large Teflon film reactors, the constant positive pressure is important to minimize the introduction of enclosure air into the reactor that may otherwise result.

As indicated in Figure 1, the floor of the reac tors has openings for a high volume mixing system for mixing reactants within a reactor and also for ex changing reactants between the reactors to achieve3 20 ft. 20 ft. 20 ft. This volume kept clear to maintain light uniformity

Temperature controlled room flushed with purified air and with reflective material on all inner surfaces Dual Teflon Reactors

Two air Handlers are located in the corners on each side of the light

(not shown).

Gas sample lines to laboratory below Access Door 200 KW Arc Light 2 Banks of Blacklights

SEMS (PM) Instrument Floor Frame Movable top frame allows

reactors to

collapse

under
pressure control

Mixing System

Under floor of reactors

Figure 1. Schematic of the UCR EPA environmental chamber reactors and enclosure.

0.0 0.2 0.4 0.6 0.8

0.300 0.350 0.400 0.450 0.500 0.550 0.600 Wavelength (microns) Arc Light Blacklights Solar Z=0

0.00 0.02 0.04 0.06 0.08 0.10 0.12

0.290 0.300 0.310 0.320Relative Intensity (Normalized to givesame NO2photolysis rate)

Figure 2. Spectrum of the light sources used in the UCR EPA chamber, with intensities normalized to give the same NO 2 photolysis rates. A representative solar spectrum is also shown.4 equal concentrations in each. This utilizes four 10” Teflon pipes with Teflon-coated blowers and flanges to either blow air from one side of a reactor to the ot her, or to move air between each of the two reactors. Teflon-coated air-driven metal valves ar e used to close off the openings to the mixing system when not in use, and during the irradiation experiments.

An AADCO air purification system that provides dry purified air at flow rates up to 1500 liters min -1 is used to supply the air to flush the enclos ure and to flush and f ill the reactors between experiments. The air is further purified by passing it through cartridges filled with Purafil® and heated Carulite 300® which is a Hopcalite® type catalyst and al so through a filter to remove particulate matter. The measured NO x , CO, and non-methane organic concentrations in the purified air were found to be less than the detection limits of the instrumentation employed (see Analytical Equipment, below).

The chamber enclosure is located on the second floor of a two-floor laboratory building that was designed and constructed specifically to house this f acility (Carter et al, 2002). Most of the analytical instrumentation is located on the ground floor beneat h the chamber, with sampling lines leading down as indicated in Figure 1.

Analytical Instrumentation

Table 1 gives a listing of the analytical and ch aracterization instrumentation whose data were utilized for this project. Other instrumentation was ava ilable and used for some of these experiments, as discussed by Carter 2002a and Carter et al, 2005a, but the data obtained were not characterized for modeling and thus not used in the mechanism evalua tions for this project. The table includes a brief description of the equipment, species monitored, a nd their approximate sensitivities, where applicable. These are discussed further in the following sections.

Ozone, CO, NO, and NO y were monitored using commercially available instruments as indicated in Table 1. The instruments were spanned for NO, NO 2 , and CO and zeroed prior to all experiments using the gas calibration system indicated in Table 1, and a prepared calibration gas cylinder with known amounts of NO and CO. O 3 and NO 2 spans were conducted by gas phase titration using the calibrator during this period. Span and zero corrections were made to the NO, NO 2 , and CO data as appropriate based on the results of these sp an measurements, and the O 3 spans indicated that the UV absorption instrument was performing within its specifications.

Organic reactants were measured by gas chro matography with FID detection as described elsewhere (Carter et al, 1995a); see also Table 1. Th e surrogate gaseous compounds ethylene, propylene, n-butane and trans-2-butene were monitored by usin g 30 m megabore GS-Alumina column and the loop sampling system. The second signal of the same GC outfitted with FID, loop sampling system and 30 m megabore DB-5 column was used to analyze surro gate liquid components toluene, n-octane and mxylene. The sampling methods employed for injecti ng the sample with the test compounds on the GC column depended on the volatility or “stickiness” of the compounds. For analyses of more volatile specie such as 2,3,3,3-tetrafluoropropene the same loop method was suitable.

Both the GC instruments were controlled and their data were analyzed using Agilent ChemStation software installed on a dedicated PC. The GC's were spanned using the prepared calibration cylinder with known amounts of ethylene, propane, prop ylene, n-butane, n-hexane, toluene, n-octane and m-xylene in ultrapure nitrogen. Analyses of the span mixture were conducted approximately every day an experiment was run, and the results were tracked for consistency.5 Table 1. List of analytical and characterization instrumentation for the UCR EPA chamber.

Type Model or Description Species Sensitivity Comments

Ozone Analyzer Dasibi Model 1003-AH. UV absorption analysis. O 3 2 ppb Standard monitoring instrument.

NO 1 ppb NO - NO y Analyzer Teco Model 42 C with external converter. Chemiluminescent analysis for NO, NOy by catalytic conversion. NO y 1 ppb Useful for NO and initial NO 2 monitoring. Converter close-coupled to the reactors so the “NO y ” channel should include HNO 3 as well as NO 2 , PANs, organic nitrates, and other species converted to NO by the catalyst. CO Analyzer Thermo Environmental Instruments Inc. Model 48 C CO 50 ppb Standard monitoring instrument

GC-FID Instruments Dual Agilent 6890 Series II GC with dual columns, loop injectors and FID detectors. Controlled by computer interfaced to network. VOCs ~10 ppbC 30 m x 0.53 mm GS-Alumina column used for the analysis of light hydrocarbons such as ethylene, propylene, n-butane and trans-2-butene and 30 m x 0.53 mm DB-5 column used for the analysis of C 5+ alkanes and aromatics, such as toluene and m-xylene. Loop injection is suitable for low to medium volatility VOCs that are not too “sticky” to pass through valves. Two 30 m x 0.32 mm DB-5 column measure C 5+ alkanes and aromatics, such as toluene and m-xylene.

Gas Calibrator Model 146C Thermo Environmental Dynamic Gas Calibrator N/A N/A Used for calibration of NO x and other analyzers. Instrument acquired early in project and under continuous use.

Data Acquisition Sytem Windows PC with custom LabView software, 16 analoginput, 40 I/O, 16 thermocouple, and 8 RS-232 channels. N/A N/A Used to collect data from most monitoring instruments and control sampling solenoids. In-house LabView software was developed using software developed by Sonoma Technology for ARB for the Central California Air Quality Study as the starting point.
Temperature

sensors Various thermocouples, radiation shielded thermocouple housing Tempera
-ture ~0.1 o C Primary measurement is thermocouples inside reactor. However, comparison with temperature measurements in the sample line suggest that irradiative heating may bias these data high by ~2.5 o C (Carter, 2004). Humidity Monitor General Eastern HYGRO-M1 Dew Point Monitor Humidity Dew point range: -40 - 50 o C Instrument performs as expected, but dew point below the performance range for most of the experiments discussed in this report, except for those with added humidity.Table 1 (continued)

6 Type Model or Description Species Sensitivity Comments

Spectroradiometer LiCor LI-1800 Spectroradiometer 300-850 nm Light

Spectrum Adequate Resolution relatively low but adequate for this project. Used to obtain relative spectrum. Also gives an absolute intensity measurement on surface useful for assessing relative trends.
QSL Spherical Irradiance Sensor Biospherical QSL-2100 PAR Irradiance Sensor. Responds to 400-700 nm light. SphericalBroadband Light Intensity Adequate Provides a measure of absolute intensity and light uniformity that is more directly related to photolysis rates than light intensity on surface. Gives more precise measurement of light intensity trends than NO 2 actinometry, but is relatively sensitive to small changes in position. Scanning Mobility Particle Sizer (SMPS) TSI 3080L column, TSI 3077
85 Kr neutralizer, and TSI 3771 CPC. Instrument design, control, and operation Similar to that described in Cocker et al. (2001) Aerosol number and sizedistributions Adequate Provides information on size distribution of aerosols in the 28-735 nm size range, which accounts for most of the aerosol mass formed in our experiments. Data can be used to assess effects of VOCs on secondary PM formation.

The surrogate components analyzed by the above syst em were calibrated by repeated analysis of a standard mixture containing these compounds, and verified by injecting and sampling known amounts of the compound in calibration chamber of known volume. The amounts of gaseous compounds injected were determined by vacuum methods, using an MKS Baratron precision pressure gauge, and bulbs of known volume, determined by weighing when fill ed with water. The amounts of liquid compounds injected were determined by measuring amounts inject ed using microliter syringes. The volumes of the calibration chambers were determined by injecting and analyzing compounds whose analyses have been calibrated previously.

The GC analysis of 2,3,3,3-tetrafluoropropene was calibrated by injecting a quantitative amount of the compound in the chamber reactors. The ch amber reactors have a known volume and therefore contain a known concentration of the injected compound. The calibration factor was then determined as a result of the GC analyses conducted prior to the start of the irradiations.

As indicated in Table 1, aerosol number and size distributions were also measured in conjunction with our experiments. The instrumentation employed is similar to that described by Cocker et al. (2001), and is the same as employed in our previous studies of coatings VOCs (Carter et al, 2005b). Particle size distributions are obtained using a scanning mobilit y particle sizer (SMPS) equipped with a 3077 85 Kr charger, a 3081L cylindrical long column, and a 3771 c ondensation particle counter (CPC). Flow rates of 2.5 LPM and 0.25 LPM for sheath and aerosol flow, respectively, are maintained using Labview 6.0- assisted PID control of MKS proportional solenoid cont rol valves. Both the sheath and aerosol flow are obtained from the reactor enclosure. The data inve rsion algorithm described by Collins et al (2002) converts CPC counts versus time to particle size distribution.

Most of the instruments other than the GCs and aerosol instrument were interfaced to a PC-based computer data acquisition system under the control of a LabView program written for this purpose. These data, and the GC data from the Agilent ChemSta tion computer, were collected over the CE-CERT7 computer network and merged into Excel files that ar e used for applying span, zero, and other corrections, and preparation of the data for modeling.

Sampling methods

Samples for analysis by the continuous monitori ng instruments were withdrawn alternately from the two reactors and zero air, under the control of sole noid valves that were in turn controlled by the data acquisition system discussed above. For most expe riments the sampling cycle was 5 minutes for each reactor, the zero air, or (for control purposes) the chamber enclosure. The program controlling the sampling sent data to the data acquisition program to indicate which state was being sampled, so the data could be appropriately apportioned when being processed. Data taken less than 3-4 minutes after the sample switched were not used for subsequent data processing. The sampling system employed is described in more detail by Carter (2002).

Samples for GC analysis of surrogate compounds were taken at approximately every 20-minute directly from each of the reactors through the separate sample lines attached to the bottom of the reactors. The GC sample loops were flushed for a desired time with the air from th e reactor being sampled.

Characterization Methods

Use of chamber data for mechanism evaluation requ ires that the conditions of the experiments be adequately characterized. This includes measurement s of temperature, humidity, light and wall effects characterization. Wall effects characterization is di scussed in detail by Carter (2004) and updated by Carter and Malkina (2005) and Carter (2007) and most of that discussion is applicable to the experiments for this project. The instrumentation used for the other characterization measurements is summarized in Table 1, above, and these measurements are discussed further below.

Temperature was monitored during chamber experi ments using calibrated thermocouples attached to thermocouple boards on our computer data acquisition system. The temperature in each of the reactors was continuously measured using relatively fi ne gauge thermocouples that were located ~1 foot above the floor of the reactors. These thermocoupl es were not shielded from the light, though it was hoped that irradiative heating would be minimized because of their small size. Experiments where the thermocouple for one of the reactors was relocated to inside the sample line indicated that radiative heating is probably non-negligible, and that a correct ion needs to be made for this by subtracting ~2.5 o C from the readings of the thermocouples in the reactors. This is discussed by Carter (2004).

Light Spectrum and Intensity . The spectrum of the light source in the 300-850 nm region was measured using a LiCor LI-1800 spect roradiometer, which is periodically calibrated at the factory. Spectroradiometer readings were taken periodically, though the relative spectra were found to have very little variation during the course of these experiments. The absolute light intensity is measured by carrying out NO 2 actinometry experiments periodically using the quartz tube method of Zafonte et al (1977) modified as discussed by Carter et al (1995a). In most cases the quartz tube was located in front of the reactors. Since this location is closer to the light than the centers of the reactors, the measurement at this location is expected to be biased high, so th e primary utility of these data are to assess potential variation of intensity over time. However, several special actinometry experiments were conducted prior to the experiments carried out for this project where the quartz tube was located inside the reactors, to provide a direct measurement of the NO 2 photolysis rates inside the reactors. The photolysis rates used when modeling these experiments were the same as u sed by Carter (2009b) when modeling the recently completed experiments for trans 1,3,3,3-tetrafluoropropene.8 Experimental Procedures

The reaction bags were collapsed to the mini mum volume by lowering the top frames, then cleaned by emptying and refilling them at least six tim es after each experiment, a nd then filled with dry purified air on the nights before experiments. Span measurements were generally made on the continuous instruments prior to injecting the r eactants for the experiments. The re actants were then injected through Teflon injection lines (that are separate from the samp ling lines) leading from the laboratory below to the reactors. The common reactants were injected in bot h reactors simultaneously, and were mixed by using the reactor-to-reactor exchange blowers and pipes fo r 10 minutes. The valves to the exchange system were then closed and the other reactants were inject ed to their respective sides and mixed using the inreactor mixing blowers and pipes for 1 minute. The c ontents of the chamber were then monitored for at least 30 minutes prior to irradiation, and samples were taken from each reactor for GC analysis.

Once the initial reactants are injected, stabilized, and sampled, the light or lights employed (argon arc or blacklights) are turned on to begin the ir radiation. During the irradiation the contents of the reactors are kept at a constant positive pressure by lowering the top frames as needed, under positive pressure control. The reactor volumes therefore decrease during the course of the experiments, in part due to sample withdrawal and in part due to small leaks in the reactor. A typical irradiation experiment ended after about 6 hours, by which time the reactors are typically down to about half their fully filled volume. Larger leaks are manifested by more rapid decline of reactor volumes, and the run is aborted early if the volume declines to about 1/3 the maximum. This was the case for a few of the experiments discussed in this report. After the irradiation the reactors we re emptied and filled six times as indicated above.

The procedures for injecting the various types of reactants were as follows. The NO, and NO 2 were prepared for injection using a vacuum rack. Known pressures of NO, measured with MKS Baratron capacitance manometers, were expanded into Pyrex bulbs with known volumes, which were then filled with nitrogen (for NO) or purified air (for NO 2 ). In order to maintain constant NO/NO 2 ratios the same two bulbs of specified volume were utilized in most of experiments. The contents of the bulbs were then flushed into the reactor(s) with nitrogen. Some of the gaseous reactants such as propylene (other than for surrogate experiments) and 2,3,3,3- tetrafluoropropene were prepared for injection using a high vacuum rack as well. For experiments with added CO, the CO was purified by passing it through an in-line activated charcoal trap and flushing it into the react or at a known rate for the amount of time required to obtain the desired concentration. Measured volumes of volatile liquid reactants were injected, using a micro syringe, into a 2 ft long Pyrex injection tube surrounded with heat tape and equipped with one port for the injection of the liquid and other ports to atta ch bulbs with gas reactants . For injections into both reactors (e.g, the NO x and base ROG surrogate components in in cremental reactivity experiments), one end of the injection tube was attached to the “Y”- shape glass tube (equipped with stopcocks) that was connected to reactors and the other end of injec tion tube was connected to a nitrogen source. The injections into a single reactor (e.g., for 2,3,3,3-te trafluoropropene in the reactivity experiments) was similar except the “Y” tube was not used.

The procedures for injection of the hydrocar bon surrogate components were as follows. A cylinder containing n-butane, trans-2-butene, propylene and ethylene in nitrogen, was used for injecting the gaseous components of the surrogate. The cylinder was attached to the injection system and a gas stream was introduced into reactors at controlled flow for certain time to obtain desired concentrations. A prepared liquid mixture with the appropriate ratios of toluene, n-octane and m-xylene was utilized for injection of these surrogate components, using the procedures as discussed above for pure liquid reactants. All the gas and liquid reactants intended to be the same in both reactors were injected at the same time. The injection consisted of opening the stopcocks and flushing the contents of the bulbs and the liquid reactants with nitrogen, with the liquid reactants being heated slightly using heat that surrounded the injection tube. The flushing continued for approximately 10 minutes.9 Problems were encountered during the injections of the surrogate components for some of the experiments for this project, resulting from concen trations different from those intended in the experimental design. This is indicated where appli cable in the table in the Results section giving the chronological summary of the experiments. Although the initial concentrations were different from those intended, the results were still useful for mechanis m testing, and modeling these experiments are included among the results. The primary consequence of these injection problems was a larger number of experiments being conducted with this compound than was initially intended.

The 2,3,3,3-tetrafluoropropene used in these e xperiments was provided as a gas in a lecture bottle, and was injected into the chamber using vacuum injection methods similar to that discussed above for NO and other gaseous reactants.

Materials

The sources of the NO, CO and the various b ase case surrogate compounds came from various commercial vendors as employed in previous projects at our laboratory. The 2,3,3,3-tetrafluoropropene, with a stated purity of ≥ 99.9%, was provided by Honeywell. No significant impurities were detected in any of the GC analyses of these samples.10 

### MECHANISM AND MODELING METHODS

Base Mechanism

The starting point for the chemical mechanis m evaluated in this work is the SAPRC-07 mechanism as documented by Carter (2009a). This is a complete update of the SAPRC-99 mechanism of Carter (2000a), but it is very similar to it in its majo r features. The reactions and rate constants in this mechanism are given in tables in Appendix A to th is report, and complete documentation of this mechanism is given by Carter (2009a). Files and so ftware implementing this chemical mechanism are available at the SAPRC mechanism web site 1 , with the chemical mechanism simulation computer programs available there being essentially the same as those employed in this work.

As discussed previously (Carter, 2000a,b, 2009a), the current SAPRC mechanisms consists of a “base mechanism” that represents th e reactions of the inorganic species and common organic products and lumped organic radical model species and “ope rators”, and separate me chanisms for the initial reactions of the many types other organic compounds that are not in the base mechanism. The compounds, or groups of compounds, that are not included in the base mechanism but for which mechanism assignments have been made, are referred to as detailed model species. The latter include all the base ROG surrogate constituents and compounds whose reactivities are being assessed (2,3,3,3- tetrafluoropropene in this case). These compounds can either be represented explicitly, with separate model species with individual reactions or sets of reactions for each, or using lumped model species similar to those employed in the “fixed parameter” version of SAPRC (Carter, 2000b, 2009a). The latter approach is used when modeling complex mixtures in ambient simulations or si mulations of experiments with complex mixtures, but the other approach, representing each compound explicitly, is more appropriate when evaluating mechanisms for individua l compounds or simple mixtures. This is because the purpose of mechanism evaluations against ch amber data is to assess the performance of the mechanism itself, not to assess the performance lump ing approaches. The latter is most appropriately assessed by comparing simulations of explicit and conde nsed versions of the same mechanism in ambient simulations.

In this work, all of the organic constituents in the environmental chamber experiments were represented explicitly using separate model species fo r each compound, while complex mixture of emitted species in the atmospheric reactivity simulations were represented using the appropriate lumped model species for the fixed parameter mechanism, as indict ed in Table A-1 in Appendix A. The reactions and rate constants in the base mechanism are given in Ta ble A-2, and the photolysis rates used are given in Table A-3. These photolysis rates were calculated from applicable actinic flux or light source characterization data and absorption cross-sections and quantum yields given by Carter (2009a).

The version of the SAPRC-07 mechanism used in this work incorporated several corrections relative to the version used in our study of trans 1,3,3,3-tetrafluoropropene (Carter, 2009b), as discussed in Appendix E of Carter (2009a). The relevant correct ions primarily concern hydroperoxide reactions that are not important in affecting ozone formation a nd have no significant affect calculations of ozone impacts of these tetrafluoropropenes.

1 Reports and files concerning the latest version of the SAPRC chemical mechanisms and their associated reactivity scales are available at http ://www.cert.ucr.edu/ ~carter/SAPRC.11 Mechanism for 2,3,3,3-Tefralfuoropropene

Alkenes can react in the atmosphere with OH radicals, O 3 or NO 3 radicals, and in general all three need to be taken into account when developing mechanisms for their O 3 formation potential. The rate constants for the reactions of 2,3,3,3-tetrafluoropropene with OH radicals and O 3 have been measured to be 1.05 x 10 -12 and 2.77 x 10 -21 cm 3 molec -1 s -1 , respectively (Nielsen et al, 2007). The rate constant for the reaction with O 3 is too low for this reaction to be an im portant sink compared to reaction with OH radicals, so it can be ignored. The rate constant for reaction with NO 3 radicals have not been measured, but can be estimated by correlation between measured OH and NO 3 radical rate constants for other alkenes (e.g., see Atkinson, 1991; Calvert et al, 20 03; Carter, 2000). Based on this correlation, the rate constant for the reactions of 2,3,3,3-tetraf luoropropene is estimated to be less than 10 -22 cm 3 molec -1 s -1

, making it negligible under atmospheric conditions. Niel sen et al (2007) obtained a relatively high rate constant of 7.03 x 10 -11 cm 3 molec -1 s -1 for the reactions of this compound with chlorine atoms, but chlorine atom reactions are not expected to be important sinks for VOCs under most atmospheric conditions, including those used for ozon e reactivity assessment in this work.

Therefore, the only loss process for 2,3,3,3-tetraf luoropropene that needs to be considered in estimating its ozone impact is reaction with OH radi cals. Hurley et al (2007) studied this reaction and found that the major product was CH 3 C(O)F, with a 91 ± 6% yield. This is consistent with the following mechanism for the OH reaction, and is also consistent with mechanisms for OH reactions with most other alkenes (Calvert et al, 2003; Carter, 2000, 2008):

OH + CF 3 CF=CH 2 → CF 3 CF(OH)CH 2 · OH + CF 3 CF=CH 2 → CF 3 CF(·)CH 2 OH CF 3 CF(OH)CH 2 · + O 2 → CF 3 CF(OH)CH 2 OO· CF 3 CF(·)CH 2 OH + O 2 → CF 3 CF(OO·)CH 2 OH CF 3 CF(OH)CH 2 OO· + NO → NO 2 + CF 3 CF(OH)CH 2 O· CF 3 CF(OO·)CH 2 OH + NO → NO 2 + CF 3 CF(O·)CH 2 OH CF 3 CF(OH)CH 2 O· → CF 3 C(OH)(·)F + HCHO CF 3 CF(O·)CH 2 OH → CF 3 C(O)F + ·CH 2 OH CF 3 C(OH)(·)F + O 2 → HO 2 + CF 3 C(O)F ·CH 2 OH + O 2 → HO 2 + HCHO or overall: OH + CF 3 CF=CH 2 → CF 3 C(O)F + HCHO + HO 2 - NO + NO 2 Note that the experimental system of Hurley et al (2007) was such that the predicted formation of formaldehyde as the co-product could not be detected because formaldehyde is formed in the methyl nitrite system they used to generate the OH radicals.

An additional reaction that needs to be considered is the formation of organic nitrates as a minor route in the reaction of peroxy radicals with NO, e.g.,

CF 3 CF(OH)CH 2 OO· + NO → CF 3 CF(OH)CH 2 ONO 2 This reaction is assumed to occur ~1.5% of the time in the propene system (Carter, 2009a), but noncarbon substituents are expected to reduce the importa nce of this reaction further (Carter, 2000, and references therein), so this reaction was neglected in the initial estimates of Carter (2008). However, to fit the chamber data for trans 1,3,3,3- tetrafluoropropene, Carter (2009b) had to assume that nitrate formation in the reaction of the CF 3 CH(OH)CHFOO· and CF 3 CH(OO·)CHFOH radicals formed in that system occurred ~5% of the time. Since the radicals formed in this case is very similar and isomers of these formed from trans 1,3,3,3-tetrafluoropropene, we initially assume that overall nitrate formation also occurs 5% of the time in the 2,3,3,3-tetrafluoroprop ene system. However, as discussed below the best fit12 to the chamber data were obtained assuming that overall nitrate formation is neglig ible, so this was used in the final model developed for this project.

The secondary reactions of the products formed al so need to be considered when estimating the ozone impacts of a VOC. The reactions of formaldehyde are already incorporated in the base atmospheric chemical mechanism used in this work, which was discussed above (Carter, 2009a). CF 3 C(O)F is not expected to react at a significant rate and therefor e its subsequent reactions are ignored. It has no known means for it to react with OH radicals or other atmospheric species, and it has no light absorption in the wavelength region important in th e lower atmosphere (IUPAC, 2004).

The above discussion focuses on the reactions of the tetrafluoropropene and its oxidation products in the presence of NO x , which are the major reactions of significance in affecting their ozone impacts. However, to estimate the ultimate envi ronmental fate of this compound and its fluorinecontaining products, one needs to also cons ider the reactions in the absence of NO x , and the reactions of products formed under such conditions. The most important reactions in the absence of NO x are reactions of the peroxy radicals with HO 2 . For the initially formed peroxy ra dicals, these include the following:

CF 3 CF(OH)CH 2 OO· + HO 2 → O 2 + CF 3 CF(OH)CH 2 OOH CF 3 CF(OO·)CH 2 OH + HO 2 → O 2 + CF 3 CF(OOH)CH 2 OH CF 3 CF(OH)CH 2 OOH + OH → H 2 O + CF 3 CF(OH)CH 2 OO· CF 3 CF(OO·)CH 2 OH + OH → H 2 O + CF 3 CF(OO·)CH 2 OH CF 3 CF(OH)CH 2 OOH + h ν → CF 3 CF(OH)CH 2 O· + OH CF 3 CF(OO·)CH 2 OH + h ν → CF 3 CF(O·)CH 2 OH + OH The subsequent reactions of the alkoxy radicals formed in the photolyses are as shown above, and the rate constants and photolysis rates are estimated based on those for methyl hydroperoxide. The OH reactions may also occur by abstraction from the C-H bonds in the hydroperoxides but these pathways are estimated to be less important than reaction at the hydroperoxide group and are ignored.

Reactions of the peroxy radicals with other pero xy and acetyl peroxy radicals also need to be considered under low NO x conditions, though they are less impor tant than the reactions with HO 2 discussed above. These are estimated using the general procedures associated with the SAPRC07 mechanism, as discussed by Carter (2009a) and shown in Table 3 below.

The representation of these reactions in SAPRC-07 mechanism is given in Table 2 and Table 3, which list the model species and reactions, respectivel y. Table 2 gives a description of the model species used and footnotes to Table 3 indicate the source of the rate constants or parameters used and give additional discussion about how the mechanism was estim ated or represented. Carter (2009a) should be consulted for a more complete discussion of the chem ical operators and other species used in the SAPRC07 mechanism. A complete listing of the other reacti ons used in the SAPRC-07 mechanism for the model simulations for this study is given in Appendix A.

Representation of Chamber Conditions

The procedures used in the model simulations of the environmental chamber experiments for this project are the same as those used by Carter (2009b) for the experiments with trans 1,3,3,3- tetrafluoropropene and are based on those discussed in detail by Carter (2004) and employed in the studies of Carter and Malkina (2005) and Carter et al (2005b), updated for SAPRC-07 as discussed by Carter (2009a). Carter (2004) should be consulted fo r details of the characterization model and chamber effects parameters employed. The temperatures used when modeling were the averages of the temperatures measured in the reactors, corrected as discussed by Carter (2004).13 Table 2. List of model species added to the b ase mechanism to represent the atmospheric reactions of 2,3,3,3-tetrafluoropropene and its oxidation products

Name Description Active Species R1234YF 2,3,3,3-tetrafluoropropene CF3COF Trifluoroacetyl fluoride R2F4OOH CF 3 CF(OOH)CH 2 OH or CF 3 CF(OH)CH 2 OOH formed following the reactions of OH with the tetrafluoropropene and reaction of the s ubsequently formed peroxy radical with HO 2 . RF4OH CF 3 CF(OH)CH 2 OH or isomers formed when pero xy radicals formed following OH + tetrafluoropropene reaction reacts by disproportionation with other peroxy radicals. Steady State Species xCF3COF Formation of trifluoroacetyl fluoride from alkoxy radicals formed in peroxy radical reactions with NO and NO 3 (100% yields) and RO 2 (50% yields) yRF4OOH Formation of CF 3 CF(OOH)CH 2 OH or CF 3 CF(OH)CH 2 OOH following RO 2 + HO 2 reactions.

The light intensity for the blacklight experiments declines slowly with time when the lights are new, though the rate of decline decreases as the lights age (Carter et al, 1995a; Carter, 2004, 2007). The characterization of the light intensity for the previous set of reported experiments is discussed by Carter (2007), and based on extrapolating the light intensity assignments for the experiments carried out then to the current experiments we assign a lig ht intensity corresponding to an NO 2 photolysis rate of 0.115 min -1 for the experiments modeled in this report. Model si mulations of the control experiments for this and the trans 1,3,3,3-tetrafluoropropene project (Carter, 2009b) indicate that this is an appropriate assignment. The blacklight spectral distribution given by Carter et al (1995a) was found to be appropriate for the blacklights in this chamber and is used when modeling the runs in this chamber using the blacklight light

source.
The chamber effects parameters used when mode ling the experiments in this chamber were the same as those given by Carter (2004) except for the HONO offgasing parameters, which were derived based on results of characterization runs carried out in conjunction with these experiments as discussed below. As discussed by Carter (2004), the chamber effects model currently used for this chamber represents both the chamber radical source and background NO x offgasing by HONO offgasing, whose magnitude is determined by the chamber effects parameter RN-I, which is the ratio of the HONO offgasing rate to the NO 2 photolysis rate. The RN-I parameter that best fits the characterization data tends to vary over time depending on the conditions of the chamber, and the results of the characterization experiments applicable to modeling the experiments discussed in this report, and the assignment of the RN-I values used, are given in the Char acterization Results section, below.

The initial reactant concentrations used in the model simulations were based on the experimentally measured values. However, the calibration of the 2,3,3,3-tetrafluoropropene measurements were based on calculated amounts of compound injected and the volume of the reactors, which were measured by injecting known quantities of CO or NO x , and measuring the CO or NO x using instruments that were independently calibrated.14 Table 3. List of reactions and rate constants used to represent the atmospheric reactions of 2,3,3,3- tetrafluoropropene and its oxidation products

Rate Parameters [b] Reaction and Products [a] k(298) A Ea Refs & Notes [c]

OH + R1234YF = xHO2 + RO2C + xHCHO + xCF3COF + yR2F4OOH 1.05e-12 1

xCF3COF = CF3COF k is variable parameter: RO2RO 2
xCF3COF = #2 XC k is variab le parameter: RO2XRO 2 yR2F4OOH = R2F4OOH + #-3 XC k is variable parameter: RO2HO2 2 yR2F4OOH = RF4OH + #-3 XC k is variable parameter: RO2RO2M 2 yR2F4OOH = k is variable parameter: RO2RO 2 R2F4OOH + OH = H2O + CF3COF + HCHO + HO2 5.18e-12 3,4 R2F4OOH + HV = OH + CF3COF + HCHO + HO2 Phot Set= COOH 4,5 [a] Format of reaction listing: “=“ separates reactants from products; “# number ” indicates stoichiometric coefficient, “# coefficient {

product list }” means that the stoichiometric coefficient is applied to all the products listed. [b] Except as indicated, the rate constants are given by k(T) = A · e -Ea/RT , where the units of k and A are

cm 3 molec -1 s -1 , Ea are kcal mol -1 , T is o K, and R=0.0019872 kcal mol -1 deg -1 . If A and Ea are not given then the rate constant is assumed to be temperature independent. The following special rate constant expressions are used:
Phot Set = name : The absorption cross sections and (if applicable) quantum yields for the photolysis

reaction are given by Carter (2009a), except for "PAA", which are given below. Here, “ name ” indicates the photolysis set used. Photolysis rat es used in chamber and ambient simulations are given in Table A-3. k is variable parameter name : The rate constant is calculated us ing variable parameters that are

calculated using concentrations of various speci es. See Footnotes [c] and [e] to Table A-2 in Appendix A for a discussion of the parame ters and how they are calculated. [c] Footnotes discussing reactions or rate constants used are as follows:
1 See text for a discussion of the mechanism. The ra te constant is from Nielsen et al (2007). Overall organic nitrate formation is assumed to be negligib le because this was found to give the best fits to the chamber data, as discussed in the Results section. 2 See Carter (2009a) and footnotes to Table A-2 for a discussion of the reactions of peroxy radical operator species. xCF3COF is the operator that represents the formation of trifluoroacetyl fluoride from peroxy radical reactions. YR2F4OOH is the operator that represents the formation of tetrafluorohyderoperoxides formed when the peroxy radicals from the OH + tetrafluoropropene reactions react with HO 2 . 3 The reaction is assumed to occur primarily with OH abstracting from the OOH group, with a rate constant assumed to be the same as used for that process in the reaction of OH with methylhydroperoxide (COOH). See Table A-2. 4 The alkoxy radicals formed should be the same as those formed in the OH + tetrafluoropropene reaction, so the same overall products are assumed to be formed, i.e., HO2 + HCHO + trifluoroacetyl fluoride. 5 The photolysis is assumed to occur at the same rate as used for methyl hydroperoxide, and the products are assumed to be OH + the alkoxy radical. See Carter (2009a).15 Atmospheric Reactivity Simulations

Atmospheric reactivity model simulations were ca rried out to derive MIR and other atmospheric reactivity values for 2,3,3,3-tetrafl uoropropene. The base mechanism, scenarios, and methods used were the same as those used when cal culating the MIR and other atmospheric ozone reactivity scales for the SAPRC-07 mechanism by Carter (2009a), so the atmospheric reactivities calculated for 2,3,3,3- tetrafluoropropene reactivities in this work are directly comparable with those given by Carter (2009a) for the ~1100 other types of VOCs represented using the SAPRC-07 mechanism. The mechanism used for 2,3,3,3-tetrafluoropropene is the same as gave the b est fits to the results of the chamber simulations, as discussed in the Results section below, and is given in Table 3, above. The inputs used in the reactivity scenarios are described by Carter (1994a,b).16 

### RESULTS AND DISCUSSION

A chronological listing of the environmental chambe r experiments carried out for this project is given in Table 4. These include experiments w ith 2,3,3,3-tetrafluoropropene and appropriate characterization and control experiments needed for th e data to be useful for mechanism evaluation. The results of the characterization experiments will be di scussed first, followed by a discussion of the results of the mechanism evaluation experiments and of the model simulations of these experiments.

Characterization Results

The individual characterization experiments that are relevant to this project are summarized in Table 4. Except as discussed below, the characteriz ation results are consistent with those discussed by Carter et al (2005b), Carter and Malkina (2005, 20 07), Carter (2007) and Carter (2009b), and the same characterization parameters were used for modeling. The only chamber effect parameter that was changed when modeling the experiments for this project concerns the apparent HONO offgasing, which is believed to be responsible for both the chamber radical source and NO x offgasing effects (Carter, 2004). This is represented in the chamber effects model by the parameter RN-I, whic h is the HONO offgasing rate used in the simulations divided by the light intensity as measured by the NO 2 photolysis rate. Figure 3 shows the HONO offgasing parameters that best fit the radical or NO x - sensitive characterization experiments carried out in the UCR EPA during the period of the last three sets of reactors. Note that the best-fit parameters depend on the mechanism used (particularly the OH + NO 2 rate constant), and all these were calculated for SAPRC-07, th e mechanism used in this work.

The experiments carried out for this project start at run EPA966, so the applicable characterization data is for the last set of reactor s shown on the figure. The average RN-I parameter that fit the results of the experiments with this reactor was approximately 10 ppt, and this was used when modeling the experiments carried out for this project. Although there is a large amount of scatter in the RN-I parameter that gave the best fit to the data in these characterization experiments, it should be noted that the simulation of the surrogate - NO x incremental reactivity experiments, which are the experiments used for mechanism evaluation, are not very sensitive to this parameter. Test calculations showed that variation of this parameter within the range shown on Figure 4 has only a minor effect on the simulations of these experiments, and does not affect conclusions concerning the tetrafluoropropene mechanism that gives the best fits to the data.

For modeling purposes, we use the same chamber e ffects parameters as used by Carter (2004), Carter and Malkina (2005), Carter et al (2005b), and Carter (2007) for all the other chamber effect parameters. Simulations of the incremental reactivit y experiments are also not very sensitive to these parameters.

Other control experiments carried out during this period were two si de equivalency tests (with the same reactive organic gas surrogate - NO x mixture simultaneously irradiated in both reactors). In addition, a propene - NO x control experiment and several pure air runs were carried out previously, and the results were as expected. The results of the side equivalenc y tests indicated acceptable side equivalency and are given in Table 5, in conjunction with the resu lts of the reactivity experiments with 2,3,3,3- tetrafluoropropene, discussed below.17 Table 4. Summary of experiments carried out for this project.

Run [a] Date Type [b] Purpose and Applicable Conditions Results

966 1/8/09 Surrogate - NO x Irradiation Control for incremental reactivity experiments to test side equivalency. See Table 5 for reactant levels. Initial concentrations in the appropriate range. Relevant results are summarized on Table 5. Good side equivalency obtained.

971 1/19/09 CO - NO x Irradiation Chamber radical source characterization. 22 ppb NO x and 38 ppm CO injected into both reactors Results indicated much lower radical input rates than generally observed in such experiments, but was not completely outside the range of variability observed previously. See Figure 3.

976 2/21/09 Surrogate - NO x + 2,3,3,3-tetrafluoropropene Irradiation Incremental reactivity experiment for 2,3,3,3- tetrafluoropropene. See Table 5 for reactant levels. Initial concentrations not in the appropriate range; NO x levels lower than expected and gas ROG surrogate levels high because of an injection calculation error. No PM data. See Table 5 and Figure 4

. 981 3/19/09 Surrogate - NO x + 2,3,3,3-tetrafluoropropene Irradiation Incremental reactivity experiment for 2,3,3,3- tetrafluoropropene. See Table 5 for reactant levels. Run ended early because of probable leak in reactor. Initial concentrations not in the appropriate range; NO x levels higher than expected and gas ROG surrogate levels high because of an injection calculation error. PM data are questionable and are not used. See Table 5 and Figure 4

. 982 3/20/09 CO - Air Irradiation Chamber NO x offgasing characterization. 36 ppm CO injected into both
reactors. Results were consistent with chamber wall model used for these experiments. See Figure 3.

984 3/26/09 Surrogate - NO x + 2,3,3,3-tetrafluoropropene Irradiation Incremental reactivity experiment for 2,3,3,3- tetrafluoropropene. See Table 5 for reactant levels. Initial concentrations not in the appropriate range; gas ROG surrogate levels high because of an injection calculation error. See Table 5 and Figure 4

. 985 3/30/09 Surrogate - NO x + 2,3,3,3-tetrafluoropropene Irradiation Incremental reactivity experiment for 2,3,3,3- tetrafluoropropene. See Table 5 for reactant levels Initial concentrations not in the appropriate range; gas ROG surrogate levels high because of an injection calculation error. See Table 5 and Figure 4

.Table 4 (continued)

18 Run [a] Date Type [b] Purpose and Applicable Conditions Results

986 4/1/09 Surrogate - NO x + 2,3,3,3-tetrafluoropropene Irradiation Incremental reactivity experiment for 2,3,3,3- tetrafluoropropene. See Table 5 for reactant levels Initial concentrations not in the appropriate range; gas ROG surrogate levels high because of an injection calculation error. See Table 5 and Figure 4

. 990 4/8/09 Surrogate - NO x + 2,3,3,3-tetrafluoropropene Irradiation Incremental reactivity experiment for 2,3,3,3- tetrafluoropropene. See Table 5 for reactant levels. Base case is standard MIR conditions Initial concentrations in the appropriate range. See Table 5 and Figure 4

. No useable PM data.

991 4/9/09 Surrogate - NO x + perfluorohexane Irradiation Control for incremental reactivity experiments to test side equivalency and to verify that the addition of the perfluoro n-hexane dilution tracer does not affect reactivity results. Standard MIR conditions except that 3.5 ppm pefluorohexane added to Side A. See Table 5 for other reactant levels.. Initial concentrations in the appropriate range. Relevant results are summarized on Table 5. Good side equivalency obtained. As expected, the presence ofperfluorohexane did not affect the gasphase results. No useable PM data.

992 4/10/09 Surrogate - NO x + 2,3,3,3-tetrafluoropropene Irradiation Incremental reactivity experiment for 2,3,3,3- tetrafluoropropene. See Table 5 for reactant levels. Base case is standard MIR conditions Injected NO x levels lower than intended due to injection error . See Table 5 and Figure 4

.

1000 4/23/09 CO - air irradiation and halopropene light decay test. ~65 ppm of CO and ~ 1 ppm each of 2,3,3,3- tetrafluoropropene, trans 1,3,3,3-tetrafluoropropene, another halogenated propene, perfluorohexane and n-butane were injected into both reactors and irradiated. [a] The ozone formation in this experiment was consistent with that expected using the standard chamber characterization model. See Figure 3. The fluoropropene results indicated that concentrations of 2,3,3,3-tetrafluoropropene decline at the same rates as CO and n-butane, which is attributable to dilution. However, the added trans 1,3,3,3-tetrafluoropropene and another halopropene declined in the reactor slightly faster than can be accounted for gas-phase processes.

1004 5/3/09 CO - NO x Irradiation 40 ppb of CO and 20 ppb of NOx and ~50 ppb perfluorohexane injected into both reactors. The NO oxidation rate in this experiment was in the range expected using the standard chamber characterization model. See Figure 3.Table 4 (continued)

19 Run [a] Date Type [b] Purpose and Applicable Conditions Results

1005 5/4/09 Surrogate - NO x + 2,3,3,3-tetrafluoropropene Irradiation Incremental reactivity experiment for 2,3,3,3- tetrafluoropropene. See Table 5 for reactant levels. Base case is standard MIR conditions. Run had to be ended just after 5 hours because of leakage in base case reactor. Initial concentrations in the appropriate range. M-Xylene data for test experiment, and therefore IntOH reactivity data, questionable and inconsistent with data from other GC instruments. See Table 5 and Figure 4. [a] Gaps in run number indicate experiments w hose data were not useful for this project.. [b] All experiments are ~6-hour irradiations using blacklights. "Surrogate" indicates a ROG surrogate - NO x mixture irradiated; "MIR" and "MOIR/2" mean the target initial NO x and base ROG surrogate were 30 ppb and 0.55 ppmC and 25 ppb and 1.1 ppm C, respectively. "Incremental Reactivity" indicates that a reactant was added to one of the two reactors. [c] The purpose of injecting the n-butane and hal opropenes was to test whether consumption of halopropenes occur at faster rates in this reactor than can be accounted for by gas-phase processes. Loss of these compounds by reaction with OH radical s is calculated to be negligible under the conditions of these experiments. The n-butane was injected as a control and dilution tracer because it is known not to have unknown loss processes and can be analyzed with precision. The perfluorohexane data were not useful as a tracer because of GC interferences.

0 5 10 15 20

500 550 600 650 700 750 800 850 900 950 1000

EPA Run NumberHONO Input Parameter (RN-I) (ppt) Radical sensitive (Side A)

Radical sensitive (Side B)

NOx sensitive (Side A)

NOx sensitive (Side B)

Humidified

Used in Model

Replaced Reactors

Figure 3. Plots of best fit HONO offgasing parameters against UCR EPA run number.20 Incremental Reactivity and Mechanism Evaluation Results

The conditions and selected results of the incremen tal reactivity experiments used to evaluate the 2,3,3,3-tetrafluoropropene mechanism are summari zed on Table 5. These experiments consist of irradiations of a reactive organic gas (ROG) - NO x mixture serving as a simplified model of the chemical system involved on O 3 formation in urban atmospheres, together in irradiations of the same mixture with 2,3,3,3-tetrafluoropropene (the test compound) adde d. The experiment without the added test compound is referred to as the "base case" experiment, and the experiment where the test compound is added is the "test" experiment. The differences in O 3 formation and other measures of reactivity in these experiments provide a measure of the effects of the test compound in a system more closely representing atmospheric conditions than the simpler experiments discussed a bove, and provide a more realistic test of the mechanism's ability to predict its atmospheric reactivity.

As in previous incremental reactivity experime nts carried out in this chamber (Carter and Malkina, 2005, 2007; Carter et al, 2005b), the plan fo r this project was to carry out two types of base case experiments. The first is a lower ROG/NO x experiment designed to approximate conditions where O 3 formation is most sensitive to VOC emissions, which serve as the basis for the MIR reactivity scale, and are referred to as "MIR" experiment s. The second is at higher ROG/NO x ratios with NO x levels at approximately half that yielding maximum ozone concentrations, and are referred to as "MOIR/2" experiments. For the MIR experiments the target initial NO x was approximately 30 ppb and the target initial base case ROG was approximately 0.6 ppmC, while for the MOIR/2 experiments the target initial levels were approximately 25 ppb and 2.3 ppmC, respectively. In both cases, the base ROG surrogate mixture representing reactive organic gases from all s ources consists of n-butane, n-octane, ethene, propene, trans-2-butene, toluene and m-xylene, and is based on a mixture derived previously (Carter et al, 1995b) as a simplification of ambient mixtures used in the atmospheric reactivity calculations. Earlier versions of this mixture also contained formaldehyde, but this w as not included in the current experiments for experimental reasons. As discussed by Carter and Malkina (2005), this does not significantly affect the utility of the experiments for mechanism evaluation.

Although the plan for the project was to carry out several MIR and MOIR/2 experiments, problems were encountered in the calculations of inj ections or the injection procedures for many of the experiments, resulting in initial concentrations being different than those intended. These cases are noted where applicable in Table 4 and Table 5. Since the in jection errors were applicable for both the base case and the added test compound side, these experime nts were still valid as incremental reactivity experiments. Although these experiments did not have the desired initial base case ROG and/or NO x levels, they were still useful for mechanism ev aluation because the variability in initial reactant concentrations are taken into account in the mo del calculations The net effect of including these experiments is that the mechanism is evaluated under a wider range of conditions than would otherwise be the case. The experiments modeled include one MI R experiment and a number of experiments with lower ROG/NO x levels, so the conditions intended to be used in the project plan are included.

The measures of gas-phase reactivity used to evaluate the mechanisms in the incremental reactivity experiments are the effects of the test compound on ∆ ([O 3 ]-[NO]), or ([O 3 ] t -[NO] t )-([O 3 ] 0 - [NO] 0 ), and IntOH, the integrated OH radical levels. As discussed elsewhere (e.g., Johnson, 1983; Carter and Atkinson, 1987; Carter and Lurm ann, 1991, Carter et al, 1993), ∆ ([O 3 ]-[NO]) gives a direct measure of the amount of conversion of NO to NO 2 by peroxy radicals formed in the photooxidation reactions, which is the process that is directly responsible for oz one formation in the atmosphere. This gives a useful measure of factors affecting O 3 reactivity even early in the experiments where O 3 formation is suppressed by the unreacted NO. Although this is the primary measure of the effect of the VOC on O 3 formation, the21 Table 5. Summary of initial concentrations a nd selected gas-phase results of the incremental reactivity experiments.

Base Run Initial Concentrations 5 Hr O 3 (ppb) D([O 3 ]-[NO]) Change (ppb) IntOH change 5 Hr PM ( μ g/m 3 ) EPA Run No. Test Side Test Cmpd Added (ppm) NO x (ppb) ROG (ppmC) Base Test 2 Hr 5 Hr (pptmin) Base Test

Side Equivalency or added Perfluorohexane Experiments 966 A 22 1.23 89 89 3 0 0 0.36 0.31 991 A 3.49 [a] 33 0.54 37 37 1 0 1 [b] [b] Added 2,3,3,3-Tetrafluoropr opene Experiments (in order of increasing base case ROG/NO x ) 1005 A 2.12 32 0.54 29 111 33 -46 18 [b] [b] 990 B 1.82 33 0.64 52 125 37 73 [b] [b] [b] 986 B 2.18 34 1.44 [c] 117 152 34 34 -4 0.01 0.01 985 B 1.12 25 1.54 [c] 107 122 10 15 -3 0.05 0.04 981 B 1.26 41 2.61 [c] [b] [b] 14 [b] [b] [b] [b] 992 A 2.37 15 [d] 1.06 72 101 22 29 -7 0.23 0.02 976 A 1.05 13 [d] 1.31 [c] 82 95 8 10 -2 0.11 0.04 984 B 1.11 23 3.13 [c] 91 98 3 7 0 0.26 0.26 [a] Run carried out with added prefluorohexane to verify that this compound is unreactive and its presence would not affect reactivity results. [b] No useable data obtained or e xperiment ended before 5 hours. [c] Gaseous base ROG components (ethene, propene, an d trans-2-butene) high by a factor of 3.6 due to reactant injection calculation error. [c] Initial NO x levels lower than intended due to NO x injection problems.

effect on radical levels is also a useful measure for mechanism evaluation, because radical levels affect how rapidly all VOCs present, including the base ROG components, react to form ozone.

The integrated OH radical levels are not measured directly, but can be derived from the amounts of consumption of reactive VOCs that react onl y with OH radical levels. In particular,

tracer t 0 t kOH Dt ) ] tracer [ ] tracer [ ln( IntOH −

= (I)

where [tracer] 0 and [tracer] t are the initial and time t concentrations of the compound used as the OH tracer, kOH tracer its OH rate constant, and D is the dilution rate in the experiments. The latter is neglected in our IntOH analysis. The base ROG surrogate compone nt m-xylene was used as the tracer to derive the IntOH levels in these experiments. The OH + m-xylene rate consta nt used was 2.36 x 10 -11 cm 3 molec -1 s -1 (Atkinson, 1989).

Plots of experimental ∆ ([O 3 ]-[NO]) in the base case and test experiments, changes in ∆ ([O3]-[NO]) and IntOH caused by adding the 2,3,3, 3-tetrafluoropropene, are shown on Figure 4 and changes in these quantities are also summarized on Ta ble 5. It can be seen that the addition of the tetrafluoropropene caused a measurable increase in NO oxidation and O 3 formation in all the experiments, though the increase was small in some of the experiments with high ROG/NO x ratios and lower amount of test compound added. The effect of adding a given amount of the tetrafluoropropene on ∆ ([O 3 ]-[NO])22 EPA1005A EPA990B EPA986B EPA985B (2.1 ppm added) (1.8 ppm added) (2.2 ppm added) (1.1 ppm added)

∆ (O 3 -NO) (ppm) vs Hour

IR ∆ (O 3 -NO) (mole basis) vs Hour

IR IntOH ( ppt-min/ppm ) vs Hour

n-C 6 F 14 (ppm) vs Hour

2,3,3,3-Tetrafluoropropene (ppm) vs Hour 0.00 0.04 0.08 0.12 0.16

0123456

0.00 0.01 0.02 0.03 0.04 0.05

0123456

-2 -1 0 1 2

0123456 0.00 0.05 0.10 0.15 0.20

0123456

0.000 0.005 0.010 0.015 0.020 0.025

0123456

-3 -2 -1 0 1

0123456 0.00 0.04 0.08 0.12 0.16

0123456

0.000 0.005 0.010 0.015 0.020

0123456

-4 -3 -2 -1 0 1

0123456 0.00 0.05 0.10 0.15

012345

0.00 0.01 0.02 0.03 0.04 0.05

012345

-4 0 4 8

012345 Questionable data after 2 hrs.

Base Experiment Test Experiment B
Model Used 5% Nitrate calc 0.0728 0.0730 0.0732 0.0734

0123456 0.067 0.068 0.069 0.070 0.071

0123456 0.075 0.076 0.077 0.078

0123456 0.061 0.062 0.063 0.064

012345

1.72 1.76 1.80 1.84

0123456 2.04 2.08 2.12 2.16 2.20

0123456 1.06 1.08 1.10 1.12 1.14

0123456 2.04 2.08 2.12

012345

Figure 4a. Experimental and calculated results of the incremental reactivity experiments with added 2,3,3,3-tetrafluoropropene (part 1 of 2).23 EPA981B EPA992A EPA976A EPA984B (1.3 ppm added) (2.4 ppm added) (1.0 ppm added) (1.1 ppm added)

∆ (O 3 -NO) (ppm) vs Hour

IR ∆ (O 3 -NO) (mole basis) vs Hour

IR IntOH ( ppt-min/ppm ) vs Hour

n-C 6 F 14 (ppm) vs Hour

2,3,3,3-Tetrafluoropropene (ppm) vs Hour 0.00 0.05 0.10 0.15 0.20

01234

-0.01 0.00 0.01 0.02

01234

-2 -1 0 1 2

01234 0.00 0.04 0.08 0.12

0123456

0.000 0.004 0.008 0.012 0.016

0123456

-4 -3 -2 -1 0 1

0123456 0.00 0.04 0.08 0.12

0123456

0.000 0.004 0.008 0.012 0.016

0123456

-4 -2 0 2 4

0123456 0.00 0.04 0.08 0.12

0123456

-0.004 0.000 0.004 0.008 0.012

0123456

-2 -1 0 1 2

0123456

Base Experiment Test Experiment B
Model Used 5% Nitrate calc 0.0 0.2 0.4 0.6 0.8 1.0

01234 Not Present

0.071 0.072 0.073 0.074

0123456 0.0 0.2 0.4 0.6 0.8 1.0

0123456 Not Present

0.091 0.092 0.093 0.094

0123456 Not Present on Test Side

1.20 1.22 1.24 1.26 1.28

01234 No dilution tracer present

2.28 2.30 2.32 2.34 2.36 2.38

0123456 1.030 1.035 1.040 1.045 1.050

0123456No tetrafluoropropene consumption data

1.06 1.08 1.10 1.12

0123456 No dilution tracer present

Figure 4b Experimental and calculated results of the incremental reactivity experiments with added 2,3,3,3-tetrafluoropropene (part 2 of 2).24 was larger in the MIR experiment than the lower NO x runs, which is expected since MIR conditions are generally more sensitive to most VOCs.

The effects of the added tetrafluoropropene on the integrated OH levels in the experiments were relatively low, though generally negative. This indi cates that this compound has a tendency to inhibit radical levels in the experiments, though the effect is small. Many VOCs ha ve a tendency to inhibit overall radical levels in expe riments to varying degrees.

Results of model simulations of the incremental reactivity experiments are also shown on Figure 4. For most experiments the model simulated the ∆ ([O3]-[NO]) results of the ba se case experiment quite well. The best fits to the ∆ ([O 3 ]-[NO]) incremental reactivity data were obtained if it is assumed that no nitrate formation occurs in the overall reaction, as shown with the solid line ("model used") curves on Figure 4. It is assumed that overall nitrate formation o ccurs with a ~5% yield, which gives best fits to the data for trans 1,3,3,3-tetrafluoropropene (Carter, 2009b) , then the model has a small but consistent bias towards underpredicting ∆ ([O 3 ]-[NO]) reactivities, as shown by the dashed lines on Figure 4. Changing the overall nitrate yield has no significant effect on calculations of IntOH reactivity or the rates of tetrafluoropropene consumption.

Figure 4 also shows the experimental and mode l calculated data for the consumption of the 2,3,3,3-tetrafluoropropene during the experiment. In all cases the consumption of this compound was relatively slow and the fractions reacted were low. B ecause even relatively low levels of reactor dilution would affect consumption data for such slowly reacting compounds, in most experiments we added perfluoro n-hexane as a tracer to determine dilution rates to use when modeling these experiments. The results indicated that some dilution was occurring in some experiments but not in others, though the dilution rates were never greater than 0.5% per hour. Although small, this level of dilution did have an effect on the model simulations of the tetrafluoroprop ene consumption rate, so dilution rates adjusted to fit the perfluorohexane data were used when modeling runs where perfl uorohexane data were available.

Figure 4 shows that even after correcting for d ilution the model still had a slight tendency to underpredict the consumption rates of 2,3,3,3-tetraf luoropropene to a slight extent for most of the experiments. However, this underprediction was al so seen for n-butane, which is present in all experiments as a base ROG surrogate, and which also r eacts relatively slowly (thoug h with a rate constant that is about 2.3 times higher than the tetrafluoroprop ene. The consumption rate of the tetrafluoropropene relative to n-butane, after correction for dilution in mo st cases, agreed very well with the rate constant ratios for these two compounds, indicating that this underprediction is not a problem with the rate constants used in the mechanisms. It is apparently due to the model somewhat underpredicting OH levels in the experiments. Since the model gives reas onably good fits to the IntOH reactivity, this underprediction must be occurring to the same extent in the base case experiments, and indicates a problem with the base mechanism, not the mechanism for the 2,3,3,3-tetrafluoropropene.

Measurements of particle forma tion were also made during the course of the experiments, using the procedures discussed above and by Carter et al (2005b), and representative results are summarized on Table 5. The addition of the 2,3,3,3-tetrafluoropropen e was found to have either no measurable effect on PM formed or to decrease PM formed in the e xperiments, indicating that this compound is not a significant source of secondary organic aerosol (SOA) . This is not unexpected, since the mechanism derived for this compound does not involve formation of low volatility products. Slight inhibiting effects on SOA is similar to what Carter et al (2005a) observed for ethylene and propylene glycols, and is attributed to the slightly negative effects of thes e compounds on overall radica l levels, which causes less SOA formation from the base ROG surrogate components.25 Atmospheric Reactivity Calculation

Conditions and maximum O 3 concentrations of the ambient scenarios used for reactivity assessment are summarized on Table 6. These are the sa me scenarios as used to calculate the atmospheric reactivities of the ~1100 types of VOCs using the SAP RC-07 mechanism by Carter (2009a), and are also the same as used in previous reactivity scales calculated using the SAPRC-99 (Carter, 2000a), and SAPRC-90 (Carter, 1994a) mechanisms. All of thes e are 1-day box model scenarios with varying inversion heights, initia lly present and emitted NO x and reactive organics, and O 3 and background VOCs entrained from aloft as the inversion heights incr ease during the day (Carter, 1994a,b), with inputs designed to represent various urban areas around the United States (Baugues, 1990). As discussed previously, four types of scenarios are employed.

• Base . The base case scenarios have the NO x and other inputs as originally specified by Baugues (1990) to represent the various urban areas around the United States. Note that these are not good representations of current conditions, since ge nerally these scenarios predict much higher O 3 levels than currently occur, and these box m odel incorporate significant simplifications of transport, mixing, and emissions, and multi-day ef fects, which can be important. However, they do represent a variety of chemical conditio ns, which are the main factors reflecting relative atmospheric reactivities of VOCs. These scen arios represent a variety of relative NO x levels, which is a major factor affecting absolute and relative reactivities of VOCs (Carter and Atkinson, 1989; Carter, 1994a). For this reason, other types of scenarios, discussed below, are derived to represent standard conditions of NO x availability.

• MIR . The Maximum Incremental Reactiv ity (MIR) scenarios have the NO x inputs adjusted so that the base ROG mixture used to represen t all the anthropogenic VOC emissions has the maximum incremental reactivity relative to ozone fo rmation. All the other inputs are the same as in the base case scenarios. Although the base ROG reactivity is used to define the MIR NO x level, most other types of VOCs also have their ma ximum incremental reactivity at this same NO x level. These scenarios represent the relatively high NO x conditions where O 3 formation is the most sensitive to VOC emissions. The averages incremen tal reactivities in all these scenarios are used to derive the MIR scale that is used in regul atory applications in California (CARB 1993, 2000).

• MOIR . The Maximum Ozone Incremental Reactivity (MOIR) scenarios have the NO x inputs adjusted to give the maximum daily maximum ozone concentration. All other inputs are the same as in the base and MIR scenario s. These scenarios represent NO x conditions that are optimum for O 3 formation, which is always lower than those for MIR. The averages incremental reactivities in all these scenarios are used to derive the MOIR s cale, which can be considered as an alternative to MIR (Carter, 1994a).

• EBIR . The Equal Benefit Incremental Reactivity (EBIR) scenarios have the NO x inputs adjusted so that O 3 formation is equally sensitive to changes in total ROG or NO x inputs. All the other inputs are the same as in the base , MIR, and MOIR scenarios. The NO x inputs are always lower than those yielding maximum O 3 (MOIR), and represent the lowest NO x levels where VOC control is at least as effective as NO x control. The averages incremental reactivities in all these scenarios are used to derive the EBIR scale, wh ich is a useful complement to the MIR scale in assessing how NO x levels affect relative reactivities.

• Averaged Conditions . The averaged conditions scenarios have all inputs other than total NO x derived to represent the average fo r the base case scenarios. The NO x inputs are varied to assess how measures of reactivity depend on NO x with other inputs held constant. Incremental reactivities in the MIR, MOIR, and EBIR aver aged conditions scenarios (i.e., whose NO x inputs are adjusted to represent those respective c onditions) usually give good approximations to reactivities in those respective scales, though th ey are not used in deriving these scales.26 Table 6. Summary of conditions of scen arios used for reactivity assessment

Max O 3 (ppb) ROG / NOx Scenario Base MIR MOIR EBIR Base MIR MOIR EBIR Max Height (kM) ROG input (m.mol

m -2 ) O 3 aloft (ppb) Final H (m)

Averaged Conditions 178 225 211 3.9 5.9 9.1 1.8 15 70 1823

Atlanta, GA 171 144 176 168 7.3 3.7 5.6 7.9 2.1 12 63 2146 Austin, TX 170 153 185 175 9.3 3.5 5.4 8.2 2.1 11 85 2108 Baltimore, MD 310 243 318 293 5.2 4.0 6.2 10.1 1.2 17 84 1169 Baton Rouge, LA 234 185 234 224 6.8 4.5 6.6 8.7 1.0 11 62 968 Birmingham, AL 238 203 257 242 6.9 2.8 4.3 6.4 1.8 13 81 1770 Boston, MA 191 164 199 189 6.5 2.9 4.4 6.8 2.6 14 105 2598 Charlotte, NC 139 137 162 158 7.8 1.9 3.0 4.1 3.0 7 92 3046 Chicago, IL 284 241 320 299 11.6 4.4 6.6 9.9 1.4 25 40 1392 Cincinnati, OH 195 158 197 182 6.4 3.5 5.3 9.1 2.8 17 70 2816 Cleveland, OH 241 194 241 228 6.6 4.4 6.9 10.3 1.7 16 89 1650 Dallas, TX 184 160 202 192 4.7 4.2 6.4 9.2 2.3 18 75 2250 Denver, CO 193 161 199 187 6.3 5.0 7.6 11.6 3.4 29 57 3358 Detroit, MI 235 183 238 218 6.8 3.8 5.8 10.0 1.8 17 68 1844 El Paso, TX 175 144 175 168 6.6 4.6 7.2 10.0 2.0 12 65 2000 Hartford, CT 167 145 184 173 8.4 2.9 4.5 7.3 2.3 11 78 2318 Houston, TX 298 226 298 277 6.1 4.1 6.2 9.5 1.7 25 65 1748 Indianapolis, IN 202 156 203 191 6.6 4.0 6.5 9.8 1.7 12 52 1675 Jacksonville, FL 149 126 156 149 7.6 3.7 5.5 7.6 1.5 8 40 1485 Kansas City, MO 151 126 158 146 7.1 3.1 4.9 8.5 2.2 9 65 2200 Lake Charles, LA 288 229 305 291 7.4 3.6 5.3 7.2 0.5 7 40 457 Los Angeles, CA 558 403 559 528 7.6 5.2 8.0 11.2 0.5 23 100 503 Louisville, KY 201 162 202 192 5.5 3.3 5.1 7.4 2.5 14 75 2518 Memphis, TN 223 178 231 216 6.8 3.4 5.1 7.8 1.8 15 58 1750 Miami, FL 129 120 149 143 9.6 2.9 4.5 6.4 2.7 9 57 2720 Nashville, TN 161 146 186 175 8.0 2.6 4.0 6.0 1.6 7 50 1608 New York, NY 372 302 378 357 8.1 4.8 6.7 9.8 1.5 39 103 1512 Philadelphia, PA 234 178 234 218 6.2 4.1 6.3 9.7 1.8 19 53 1800 Phoenix, AZ 267 208 267 244 7.6 5.0 7.8 13.0 3.3 40 60 3250 Portland, OR 159 131 163 156 6.5 3.1 4.9 7.0 1.6 6 66 1575 Richmond, VA 231 181 233 214 6.2 3.6 5.5 9.4 1.9 16 64 1932 Sacramento, CA 195 150 196 183 6.6 3.9 6.0 9.1 1.1 7 60 1103 St Louis, MO 304 237 311 288 6.1 4.7 7.2 11.6 1.6 26 82 1625 Salt Lake City, UT 180 156 189 177 8.5 3.5 5.5 9.1 2.2 11 85 2150 San Antonio, TX 119 101 122 118 3.9 3.0 4.7 6.5 2.3 6 60 2308 San Diego, CA 185 146 185 177 7.1 4.7 7.2 10.1 0.9 8 90 850 San Francisco, CA 225 345 455 434 4.8 6.1 9.0 12.0 0.7 25 70 650 Tampa, FL 212 172 218 209 4.4 3.5 5.2 7.0 1.0 8 68 991 Tulsa, OK 219 171 219 202 5.3 3.5 5.4 8.8 1.8 15 70 1830 Washington, DC 272 209 273 256 5.3 3.2 4.8 7.4 1.4 13 99 142127 Table 7 gives the calculated incremental reactiv ities for 2,3,3,3-tetrafluoropropene in these various scenarios. These were calculated using the mech anism that gave the best fit to the chamber data, i.e. with the nitrate yield set at 5% (see Table 3) . The calculated incremental reactivities for ethane, the compound that has been used by the U.S. EPA as the informal standard to define "negligible" ozone impact for the purpose of exempting VOCs from regul ation as ozone precursors (Dimitriades, 1999), are also shown on the table. Plots of the incremental reactivities of 2,3,3,3-tetrafluoropropene relative to ethane against relative NO x levels are shown on Figure 5

It can be seen that although its incremental reac tivities of 2,3,3,3-tetrafluoropropene are always positive, they are relatively low, and are comparable, on a mass basis, to those for ethane. The reactivity relative to ethane shows relatively little variability from scenario to scenario , with the mass-based reactivity ratio for all scenarios being 0.9 ± 0.2. The reactivity ratio for the MIR scenarios is slightly higher being 1.04 ± 0.13, but the reactivities of these two com pounds are still well within the variability from scenario to scenario.

0.00 0.25 0.50 0.75 1.00 1.25 1.50

0.0 0.5 1.0 1.5 2.0 2.5 3.0 NOx input / MOIR NOx Input2,3,3,3-Tetrafluoropropene /Ethane Reactivity (mass basis) Base

MIR

MOIR

EBIR

Figure 5. Plots of reactivities of 2,3,3,3-tetrafl uoropropene relative to etha ne against relative NO x levels for all the scenarios used for reactivity assessment.28 Table 7. Calculated atmospheric incremental reactivities for 2,3,3,3- tetrafluoropropene and ethane.

2,3,3,3-Tetrafluoropropene Incremental Reactivity

(gm O 3 / gm VOC) Ethane Incremental Reactivity (gm O 3 / gm VOC) Scenario

Base MIR MOIR EBIR Base MIR MOIR EBIR Averaged Conditions 0.273 0.152 0.103 0.268 0.184 0.130
Reactivity Scale Value (Scenario averages) 0.135 ±0.035 0.267 ±0.047 0.151 ±0.025 0.104 ±0.018 0.162 ±0.043 0.264 ±0.065 0.184 ±0.051 0.133 ±0.038 Atlanta, GA 0.121 0.266 0.159 0.112 0.140 0.252 0.179 0.129 Austin, TX 0.103 0.268 0.162 0.112 0.132 0.276 0.208 0.146 Baltimore, MD 0.179 0.256 0.136 0.091 0.208 0.254 0.178 0.128 Baton Rouge, LA 0.131 0.232 0.139 0.097 0.123 0.196 0.129 0.090 Birmingham, AL 0.110 0.325 0.171 0.117 0.173 0.351 0.245 0.183 Boston, MA 0.112 0.259 0.152 0.109 0.155 0.276 0.201 0.149 Charlotte, NC 0.087 0.272 0.172 0.134 0.124 0.306 0.242 0.199 Chicago, IL 0.078 0.255 0.133 0.089 0.089 0.239 0.149 0.104 Cincinnati, OH 0.135 0.279 0.159 0.106 0.206 0.306 0.229 0.165 Cleveland, OH 0.150 0.236 0.143 0.097 0.164 0.217 0.158 0.115 Dallas, TX 0.230 0.237 0.139 0.094 0.236 0.232 0.165 0.116 Denver, CO 0.184 0.231 0.138 0.096 0.156 0.184 0.123 0.086 Detroit, MI 0.125 0.268 0.144 0.095 0.188 0.288 0.206 0.148 El Paso, TX 0.158 0.229 0.140 0.097 0.145 0.186 0.132 0.094 Hartford, CT 0.111 0.302 0.176 0.120 0.166 0.322 0.247 0.183 Houston, TX 0.145 0.269 0.141 0.093 0.188 0.277 0.185 0.128 Indianapolis, IN 0.159 0.289 0.163 0.111 0.191 0.280 0.194 0.138 Jacksonville, FL 0.119 0.297 0.169 0.120 0.122 0.270 0.174 0.123 Kansas City, MO 0.131 0.308 0.174 0.116 0.206 0.345 0.256 0.183 Lake Charles, LA 0.109 0.321 0.162 0.113 0.109 0.296 0.166 0.112 Los Angeles, CA 0.092 0.164 0.082 0.056 0.088 0.139 0.082 0.061 Louisville, KY 0.172 0.325 0.189 0.131 0.228 0.338 0.245 0.176 Memphis, TN 0.128 0.327 0.168 0.113 0.165 0.329 0.209 0.148 Miami, FL 0.093 0.297 0.173 0.126 0.108 0.289 0.202 0.153 Nashville, TN 0.114 0.398 0.211 0.143 0.172 0.450 0.310 0.222 New York, NY 0.094 0.207 0.115 0.080 0.075 0.158 0.091 0.065 Philadelphia, PA 0.145 0.269 0.143 0.097 0.177 0.265 0.175 0.124 Phoenix, AZ 0.144 0.249 0.139 0.086 0.194 0.261 0.190 0.131 Portland, OR 0.134 0.294 0.174 0.126 0.172 0.295 0.215 0.161 Richmond, VA 0.136 0.277 0.152 0.102 0.188 0.278 0.201 0.146 Sacramento, CA 0.141 0.303 0.160 0.105 0.191 0.307 0.208 0.146 St Louis, MO 0.159 0.226 0.123 0.083 0.171 0.211 0.144 0.103 Salt Lake City, UT 0.114 0.268 0.163 0.108 0.168 0.285 0.222 0.159 San Antonio, TX 0.192 0.240 0.149 0.110 0.223 0.247 0.186 0.140 San Diego, CA 0.110 0.176 0.108 0.078 0.099 0.143 0.097 0.070 San Francisco, CA 0.112 0.154 0.091 0.064 0.085 0.113 0.071 0.051 Tampa, FL 0.221 0.294 0.160 0.115 0.209 0.263 0.160 0.113 Tulsa, OK 0.167 0.301 0.164 0.111 0.209 0.307 0.208 0.146 Washington, DC 0.133 0.266 0.147 0.102 0.186 0.279 0.199 0.14829 

### CONCLUSIONS

This project has been successful in obtaining information needed to reduce uncertainties in estimating atmospheric ozone impacts of 2,3,3,3- tetrafluoropropene. The available kinetic and mechanistic data for this compound are sufficient to derive an atmospheric reaction mechanism for this compound that can be used to estimate its atmosp heric ozone impacts. However, the mechanism had uncertainties and estimates that needed to be tested, and experimental data were needed to establish the predictive capability of the mechanism before its pred ictions can be used as a basis for VOC exemption decisions. The experiments carried out for this proj ect were successful in establishing the predictive capability of the mechanism developed for this comp ound, though some adjustments had to be made in order for the mechanism to simulate the data. These adjustments were well within the uncertainty of the estimates, so the mechanism can now be cons idered to be reasonably well established.

The evaluated mechanism predicted that the ozone impacts of 2,3,3,3-tetrafluoropropene, on a mass basis are essentially the same as those for ethane. The reactivities rela tive to ethane averaged 0.9 ± 0.2 for all scenarios considered, and 1.0 ± 0.1 for the MIR scenarios, i.e. well within the scenario-toscenario variability of being the same. Note that all the scenarios considered are one-day simulations, and compounds that react in the atmosphere more slowly than ethane might have higher relatively higher ozone impacts in multi-day simulations. However, 2,3,3,3-tetrafluoropropene reacts somewhat more rapidly than ethane in the atmosphere, so if anythi ng its ozone impacts relative to ethane are more likely to decrease in multi-day simulations. Therefore, if etha ne is used as the standa rd to define “negligible” ozone impact for the purpose of determining VOC exemptions for ozone precursors, then 2,3,3,3- tetrafluoropropene should meet this standard.

The uncertain portion of the 2,3,3,3-tetrafluoropr opene mechanism that had to be adjusted to yield satisfactory simulations of the chamber data con cerned the nitrate yields in the reaction of NO with the initially formed HOC 3 F 4 H 2 OO· peroxy radicals. The overall nitrate yield was previously estimated to be negligible (Carter, 2008b), and indeed this mechanism th at gave best fits to the data in this study, so it was not modified as a result of this experiment al study. However, the data for trans 1,3,3,3- tetrafluoropropene were best fit if an overall nitrate yield of ~5% was assumed (Carter, 2009b), suggesting that this should have been the case for 2,3,3,3-tetrafluoropr opene as well. The fact that the best fit mechanisms suggest different nitrate yields for these tetrafluoropropenes suggest that the position of the fluorine atoms on the molecule has an effect on the overall nitrate yields in the photooxidation mechanism. Note, however, that these yields are de rived indirectly based on modeling ozone reactivity, and not direct measurements of nitrate formation.

The near-explicit mechanism developed for this compound permits predictions of the gas-phase products formed in the atmospheric oxidations of 2,3, 3,3-tetrafluoropropene. In the case of this compound the major products expected are formaldehyde, tr ifluoroacetyl fluoride, and the fluorinated hydroperoxides CF 3 CF(OH)CH 2 OOH and CF 3 CF(OOH)CH 2 OH, which are expected to react primarily to form formaldehyde and trifluoroacetyl fluoride. The formaldehyde will be prim arily oxidized to CO and CO 2 , but the trifluoroacetyl fluoride is expected to be relatively stable in the gas phase, though it presumably will eventually hydrolyze in the environm ent to HF and trifluoroacetic acid. The mechanism developed in this work could be used fo r modeling the formation of these products.

Although this was outside the stated scope of this project, data were also obtained in this project concerning the effects of 2,3,3,3-tetrafluoropropene on atmospheric particle formation. The results indicated that the addition of this compound to atmospheric reactive organic gas surrogate - NO x irradiations either had no effect on the mass or particle s formed, or slightly reduced it. This indicates that30 this compound does not form measurable amounts of s econdary organic aerosol. This is as expected, since it is not predicted to form low volatility products . Furthermore, the products that it forms apparently do not also undergo significant hete rogeneous reactions to form c ondensable compounds, at least under the relatively clean and dry cond itions of these experiments.31 

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### APPENDIX A. BASE MECHANISM LISTING

Table A-1. List of model species used in the ba se SAPRC-07 mechanism, including the VOC species used in the chamber and atmospheric reactiv ity simulations. The model species used for 2,3,3,3-tetrafluoropropene and its reaction pr oducts and intermediates are given in Table 2, above.

Name Description Constant Species. O2 Oxygen M Air H2O Water H2 Hydrogen Molecules HV Light Active Inorganic Species.
O3 Ozone NO Nitric Oxide NO2 Nitrogen Dioxide NO3 Nitrate Radical N2O5 Nitrogen Pentoxide HONO Nitrous Acid HNO3 Nitric Acid HNO4 Peroxynitric Acid HO2H Hydrogen Peroxide CO Carbon Monoxide SO2 Sulfur Dioxide H2 Hydrogen Active Radical Species and Operators. OH Hydroxyl Radicals HO2 Hydroperoxide Radicals MEO2 Methyl Peroxy Radicals RO2C Peroxy Radical Operator representing NO to NO 2 and NO 3 to NO 2 conversions, and the effects of peroxy radical reactions on acyl peroxy and other peroxy radicals. RO2XC Peroxy Radical Operator representing NO consumption (used in conjunction with organic nitrate formation), and the effects of peroxy radical reactions on NO 3 , acyl peroxy radicals, and other peroxy radicals. MECO3 Acetyl Peroxy Radicals RCO3 Peroxy Propionyl and higher peroxy acyl Radicals BZCO3 Peroxyacyl radical formed from Aromatic Aldehydes MACO3 Peroxyacyl radicals formed from methacrolein and other acroleins. Steady State Radical Species O3P Ground State Oxygen Atoms O1D Excited Oxygen Atoms TBUO t-Butoxy Radicals BZO Phenoxy RadicalsTable A-1 (continued)

36 Name Description

PAN and PAN Analogues PAN Peroxy Acetyl Nitrate PAN2 PPN and other higher alkyl PAN analogues PBZN PAN analogues formed from Aromatic Aldehydes MAPAN PAN analogue formed from Methacrolein Explicit and Lumped Molecule Reactive Organic Product Species HCHO Formaldehyde CCHO Acetaldehyde RCHO Lumped C3+ Aldehydes. Mechanism based on propionaldehyde ACET Acetone MEK Ketones and other non-alde hyde oxygenated products that react with OH radicals faster than 5 x 10 -13 but slower than 5 x 10 -12 cm 3 molec -2 sec -1 . Mechanism based on methyl ethyl ketone. MEOH Methanol HCOOH Formic Acid CCOOH Acetic Acid. Also used for peroxyacetic acid. RCOOH Higher organic acids and peroxy acids. Mechanism based on propionic acid. COOH Methyl Hydroperoxide ROOH Lumped organic hydroperoxides with 2-4 carbons. Mechanism based n-propyl hydroperoxide. R6OOH Lumped organic hydroperoxides with 5 or more carbons (other than those formed following OH addition to aromatic rings, which are repr esented separately). Mechanism based on 3- hexyl hydroperoxide. RAOOH Organic hydroperoxides formed following OH addition to aromatic rings, which is represented separately because of their proba ble role in SOA formation. Mechanism based on two isomers expected to be formed in the m-xylene system. GLY Glyoxal MGLY Methyl Glyoxal BACL Biacetyl CRES Phenols and Cresols. Mechanism based on o-cresol. NPHE Nitrophenols BALD Aromatic aldehydes. M echanism based on benzaldehyde MACR Methacrolein MVK Methyl Vinyl Ketone IPRD Lumped isoprene product species. Mechanism based on that of Carter and Atkinson (1996). Aromatic unsaturated ring fragmentation products (see discussion of aromatic mechanisms) AFG1 Lumped photoreactive monounsaturated dicarbon yl aromatic fragmentation products that photolyze to form radicals. AFG2 Lumped photoreactive monounsaturated dicarbon yl aromatic fragmentation products that photolyze to form non-radical products AFG3 Lumped diunsaturatred dicarbon yl aromatic fragmentation product.Table A-1 (continued)

37 Name Description

Lumped Parameter Products
PROD2 Ketones and other non-al dehyde oxygenated products that react with OH radicals faster than 5 x 10 -12 cm 3 molec -2 sec -1 . Mechanism based on CH 3 C(O)CH 2 CH 2 CH 2 OH, CH 3 C(O)- CH 2 CH(CH 3 )CH 2 OH, CH 3 CH 2 C(O)CH 2 CH 2 CH(CH 3 )OH, CH 3 CH 2 C(O)CH 2 CH 2 CH(OH)- CH 2 CH 3 , and CH 3 CH 2 CH 2 CH(OH)CH 2 -CH 2 C(O)CH 2 CH 3 (PROD2-1 through 5), each weighed equally. RNO3 Lumped Organic Nitrates. Mechanism based on CH 3 CH 2 CH(CH 3 )ONO 2 , CH 3 CH(OH)CH 2 - CH 2 CH 2 ONO 2 , CH 3 CH 2 CH(CH 3 )CH(CH 3 )ONO 2 , CH 3 CH 2 CH 2 CH 2 CH 2 CH(ONO 2 )CH 2 OH, CH 3 CH 2 C(CH 3 )(ONO 2 )CH 2 CH(CH 3 )CH 3 , and CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH(ONO 2 )- CH 2 CH 3 (RNO3-1 through 6), each weighed equally. Steady state operators used to represent radical or product formation in peroxy radical reactions.
xHO2 Formation of HO 2 from alkoxy radicals formed in peroxy radical reactions with NO and NO 3 (100% yields) and RO 2 (50% yields) xOH As above, but for OH xNO2 As above, but for NO 2 xMEO2 As above, but for MEO2 xMECO3 As above, but for MECO3 xRCO3 As above, but for RCO3 xMACO3 As above, but for MACO3 xTBUO As above, but for TBUO xCO As above, but for CO xHNO3 As above, but for HNO3 xHCHO As above, but for HCHO xCCHO As above, but for CCHO xRCHO As above, but for RCHO xACET As above, but for ACET xMEK As above, but for MEK xPROD2 As above, but for PROD2 xGLY As above, but for GLY xMGLY As above, but for MGLY xBACL As above, but for BACL xBALD As above, but for BALD xAFG1 As above, but for AFG1 xAFG2 As above, but for AFG2 xAFG3 As above, but for AFG3 xMACR As above, but for MACR xMVK As above, but for MVK xIPRD As above, but for IPRD xRNO3 As above, but for RNO3 xHCOOH As above, but for HCOOH xCCOOH As above, but for CCOOH xRCOOH As above, but for RCOOH zRNO3 Formation of RNO3 in the RO 2 + NO, reaction, or formation of corresponding non-nitrate products (represented by PROD2) formed from alkoxy radicals formed in RO 2 + NO 3 and (in 50% yields) RO 2 + RO 2 reactions.Table A-1 (continued)

38 Name Description yROOH Formation of ROOH following RO 2 + HO 2 reactions, or formation of H-shift disproportionation products (represented by MEK) in the RO 2 + RCO 3 and (in 50% yields) RO 2 + RO 2 reactions. yR6OOH As above, but with the RO 2 + HO 2 product represented by R6OOH and the H-shift products are represented by PROD2. yRAOOH As above, but with the RO 2 + HO 2 product represented by R6OOH Non-Reacting Species
CO2 Carbon Dioxide SULF Sulfates (SO 3 or H 2 SO 4 ) XC Lost Carbon or carbon in unreactive products XN Lost Nitrogen or nitrogen in unreactive products Primary Organics Represented explicitly
CH4 Methane ETHENE Ethene ISOPRENE Isoprene ACETYLEN Acetylene BENZENE Benzene ETHANE Ethane (not part of the base mechanism, but used in atmospheric reactivity simulations) Organics represented explicitly in the chamber simu lations (not used in the atmospheric simulations) N-C4 n-Butane N-C6 n-Hexane N-C8 n-Octane PROPENE Propene T-2-BUTE trans-2-Butene TOLUENE Toluene M-XYLENE m-Xylene Lumped model species used in the atmospheric reactivity simulations (not used in chamber simulations) ALK1 Alkanes and other non-aromatic compounds that react only with OH, and have kOH (OH radical rate constant) between 2 and 5 x 10 2 ppm -1 min -1 . (Primarily ethane) ALK2 Alkanes and other non-aromatic compo unds that react only with OH, and have kOH between 5 x 10 2 and 2.5 x 10 3 ppm -1 min -1 . (Primarily propane) ALK3 Alkanes and other non-aromatic compo unds that react only with OH, and have kOH between 2.5 x 10 3 and 5 x 10 3 ppm -1 min -1

. ALK4 Alkanes and other non-aromatic compo unds that react only with OH, and have kOH between 5 x 10 3 and 1 x 10 4 ppm -1 min -1

. ALK5 Alkanes and other non-aromatic compounds that react only with OH, and have kOH greater than 1 x 10 4 ppm-1 min-1. ARO1 Aromatics with kOH < 2x10 4 ppm -1 min -1

. ARO2 Aromatics with kOH > 2x10 4 ppm -1 min -1

. OLE1 Alkenes (other than ethene) with kOH < 7x10 4 ppm -1 min -1

. OLE2 Alkenes with kOH > 7x10 4 ppm -1 min -1

. TERP Terpenes39 Table A-2. Reactions and rate constants in the SA PRC-07 mechanism used in this work. See Carter (2009a) for documentation. The reactions used for 2,3,3,3-tetrafluoropropene are given in Table 3, above.

Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B Inorganic Reactions 1 NO2 + HV = NO + O3P Phot Set= NO2-06 2 O3P + O2 + M = O3 + M 5.68e-34 5.68e-34 0.00 -2.60 3 O3P + O3 = #2 O2 8.34e-15 8.00e-12 4.09 4 O3P + NO = NO2 1.64e-12 Falloff, F=0.60, N=1.00 0: 9.00e-32 0.00 -1.50 inf: 3.00e-11 0.00 0.00 5 O3P + NO2 = NO + O2 1.03e-11 5.50e-12 -0.37 6 O3P + NO2 = NO3 3.24e-12 Falloff, F=0.60, N=1.00 0: 2.50e-31 0.00 -1.80 inf: 2.20e-11 0.00 -0.70 7 O3 + NO = NO2 + O2 2.02e-14 3.00e-12 2.98 8 O3 + NO2 = O2 + NO3 3.72e-17 1.40e-13 4.91 9 NO + NO3 = #2 NO2 2.60e-11 1.80e-11 -0.22 10 NO + NO + O2 = #2 NO2 1.93e-38 3.30e-39 -1.05 11 NO2 + NO3 = N2O5 1.24e-12 Falloff, F=0.35, N=1.33 0: 3.60e-30 0.00 -4.10 inf: 1.90e-12 0.00 0.20 12 N2O5 = NO2 + NO3 5.69e-2 Falloff, F=0.35, N=1.33 0: 1.30e-3 21.86 -3.50 inf: 9.70e+14 22.02 0.10 13 N2O5 + H2O = #2 HNO3 2.50e-22 14 N2O5 + H2O + H2O = #2 HNO3 + H2O 1.80e-39 N2O5 + HV = NO3 + NO + O3P (Slow) N2O5 + HV = NO3 + NO2 (Slow) 15 NO2 + NO3 = NO + NO2 + O2 6.75e-16 4.50e-14 2.50 16 NO3 + HV = NO + O2 Phot Set= NO3NO-06 17 NO3 + HV = NO2 + O3P Phot Set= NO3NO2-6 18 O3 + HV = O1D + O2 Phot Set= O3O1D-06 19 O3 + HV = O3P + O2 Phot Set= O3O3P-06 20 O1D + H2O = #2 OH 1.99e-10 21 O1D + M = O3P + M 3.28e-11 2.38e-11 -0.19 22 OH + NO = HONO 7.31e-12 Falloff, F=0.60, N=1.00 0: 7.00e-31 0.00 -2.60 inf: 3.60e-11 0.00 -0.10 23 HONO + HV = OH + NO Phot Set= HONO-06 24 OH + HONO = H2O + NO2 5.95e-12 2.50e-12 -0.52 25 OH + NO2 = HNO3 1.05e-11 Falloff, F=0.60, N=1.00 0: 1.80e-30 0.00 -3.00 inf: 2.80e-11 0.00 0.00 26 OH + NO3 = HO2 + NO2 2.00e-11Table A-2 (continued)

40 Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B

27 OH + HNO3 = H2O + NO3 1.51e-13 k = k0+k3M/(1+k3M/k2) k0: 2.40e-14 -0.91 0.00 k2: 2.70e-17 -4.37 0.00 k3: 6.50e-34 -2.65 0.00 28 HNO3 + HV = OH + NO2 Phot Set= HNO3 29 OH + CO = HO2 + CO2 2.28e-13 k = k1 + k2 [M] k1: 1.44e-13 0.00 0.00 k2: 3.43e-33 0.00 0.00 30 OH + O3 = HO2 + O2 7.41e-14 1.70e-12 1.87 31 HO2 + NO = OH + NO2 8.85e-12 3.60e-12 -0.54 32 HO2 + NO2 = HNO4 1.12e-12 Falloff, F=0.60, N=1.00 0: 2.00e-31 0.00 -3.40 inf: 2.90e-12 0.00 -1.10 33 HNO4 = HO2 + NO2 1.07e-1 Falloff, F=0.60, N=1.00 0: 3.72e-5 21.16 -2.40 inf: 5.42e+15 22.20 -2.30 34 HNO4 + HV = #.61 {HO2 + NO2} + #.39 {OH + NO3} Phot Set= HNO4-06 35 HNO4 + OH = H2O + NO2 + O2 4.61e-12 1.30e-12 -0.76 36 HO2 + O3 = OH + #2 O2 2.05e-15 2.03e-16 -1.38 4.57 37 HO2 + HO2 = HO2H + O2 2.84e-12 k = k1 + k2 [M] k1: 2.20e-13 -1.19 0.00 k2: 1.90e-33 -1.95 0.00 38 HO2 + HO2 + H2O = HO2H + O2 + H2O 6.09e-30 k = k1 + k2 [M] k1: 3.08e-34 -5.56 0.00 k2: 2.66e-54 -6.32 0.00

39 NO3 + HO2 = #.8 {OH + NO2 + O2} + #.2 {HNO3 + O2} 4.00e-12

40 NO3 + NO3 = #2 NO2 + O2 2.41e-16 8.50e-13 4.87 41 HO2H + HV = #2 OH Phot Set= H2O2 42 HO2H + OH = HO2 + H2O 1.80e-12 1.80e-12 0.00 43 OH + HO2 = H2O + O2 1.10e-10 4.80e-11 -0.50 44 OH + SO2 = HO2 + SULF 9.49e-13 Falloff, F=0.60, N=1.00 0: 3.30e-31 0.00 -4.30 inf: 1.60e-12 0.00 0.00 45 OH + H2 = HO2 + H2O 7.02e-15 7.70e-12 4.17 Methyl peroxy and methoxy reactions BR01 MEO2 + NO = NO2 + HCHO + HO2 7.64e-12 2.30e-12 -0.72 BR02 MEO2 + HO2 = COOH + O2 4.65e-12 3.46e-13 -1.55 0.36 BR03 MEO2 + HO2 = HCHO + O2 + H2O 4.50e-13 3.34e-14 -1.55 -3.53 BR04 MEO2 + NO3 = HCHO + HO2 + NO2 1.30e-12 BR05 MEO2 + MEO2 = MEOH + HCHO + O2 2.16e-13 6.39e-14 -0.73 -1.80 BR06 MEO2 + MEO2 = #2 {HCHO + HO2} 1.31e-13 7.40e-13 1.03 Active Peroxy Radical Operators BR07 RO2C + NO = NO2 9.23e-12 2.60e-12 -0.76 BR08 RO2C + HO2 = HO2 7.63e-12 3.80e-13 -1.79Table A-2 (continued)

41 Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B

BR09 RO2C + NO3 = NO2 2.30e-12

BR10 RO2C + MEO2 = #.5 {RO2C + xHO2 + xHCHO + O2} + #.25 {HCHO + MEOH} 2.00e-13

BR11 RO2C + RO2C = 3.50e-14
BR12 RO2XC + NO = XN Same k as rxn BR07 BR13 RO2XC + HO2 = HO2 Same k as rxn BR08 BR14 RO2XC + NO3 = NO2 Same k as rxn BR09

BR15 RO2XC + MEO2 = #.5 {RO2C + xHO2 + xHCHO + O2} + #.25 {HCHO + MEOH} Same k as rxn BR10

BR16 RO2XC + RO2C = Same k as rxn BR11 BR17 RO2XC + RO2XC = Same k as rxn BR11 Reactions of Acyl Peroxy Radicals, PAN, and PAN analogues BR18 MECO3 + NO2 = PAN 9.37e-12 Falloff, F=0.30, N=1.41 0: 2.70e-28 0.00 -7.10 inf: 1.21e-11 0.00 -0.90 BR19 PAN = MECO3 + NO2 6.27e-4 Falloff, F=0.30, N=1.41 0: 4.90e-3 24.05 0.00 inf: 4.00e+16 27.03 0.00

BR20 PAN + HV = #.6 {MECO3 + NO2} + #.4 {MEO2 + CO2 + NO3} Phot Set= PAN

BR21 MECO3 + NO = MEO2 + CO2 + NO2 1.97e-11 7.50e-12 -0.58 BR22 MECO3 + HO2 = CCOOH + #.7 O2 + #.3 O3 1.36e-11 5.20e-13 -1.95 BR23 MECO3 + NO3 = MEO2 + CO2 + NO2 + O2 Same k as rxn BR09

BR24 MECO3 + MEO2 = #.9 {CCOOH + HCHO + O2} + #.1 {HCHO + HO2 + MEO2 + CO2} 1.06e-11 2.00e-12 -0.99

BR25 MECO3 + RO2C = CCOOH 1.56e-11 4.40e-13 -2.13 BR26 MECO3 + RO2XC = CCOOH Same k as rxn BR25 BR27 MECO3 + MECO3 = #2 {MEO2 + CO2} + O2 1.54e-11 2.90e-12 -0.99
BR28 RCO3 + NO2 = PAN2 1.21e-11 1.21e-11 0.00 -1.07 BR29 PAN2 = RCO3 + NO2 5.48e-4 8.30e+16 27.70

BR30 RCO3 + NO = NO2 + RO2C + xHO2 + yROOH + xCCHO + CO2 2.08e-11 6.70e-12 -0.68

BR31 RCO3 + HO2 = RCOOH + #.75 O2 + #.25 O3 Same k as rxn BR22

BR32 RCO3 + NO3 = NO2 + RO2C + xHO2 + yROOH + xCCHO + CO2 + O2 Same k as rxn BR09

BR33 RCO3 + MEO2 = RCOOH + HCHO + O2 Same k as rxn BR24 BR34 RCO3 + RO2C = RCOOH + O2 Same k as rxn BR25 BR35 RCO3 + RO2XC = RCOOH + O2 Same k as rxn BR25

BR36 RCO3 + MECO3 = #2 CO2 + MEO2 + RO2C + xHO2 + yROOH + xCCHO + O2 Same k as rxn BR27

BR37 RCO3 + RCO3 = #2 {RO2C + xHO2 + xCCHO + yROOH + CO2} Same k as rxn BR27

BR38 BZCO3 + NO2 = PBZN 1.37e-11 BR39 PBZN = BZCO3 + NO2 4.27e-4 7.90e+16 27.82 BR40 BZCO3 + NO = NO2 + CO2 + BZO + RO2C Same k as rxn BR30Table A-2 (continued)

42 Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B

BR41 BZCO3 + HO2 = RCOOH + #.75 O2 + #.25 O3 + #4 XC Same k as rxn BR22

BR42 BZCO3 + NO3 = NO2 + CO2 + BZO + RO2C + O2 Same k as rxn BR09 BR43 BZCO3 + MEO2 = RCOOH + HCHO + O2 + #4 XC Same k as rxn BR24 BR44 BZCO3 + RO2C = RCOOH + O2 + #4 XC Same k as rxn BR25 BR45 BZCO3 + RO2XC = RCOOH + O2 + #4 XC Same k as rxn BR25 BR46 BZCO3 + MECO3 = #2 CO2 + MEO2 + BZO + RO2C Same k as rxn BR27

BR47 BZCO3 + RCO3 = #2 CO2 + RO2C + xHO2 + yROOH + xCCHO + BZO + RO2C Same k as rxn BR27

BR48 BZCO3 + BZCO3 = #2 {BZO + RO 2C + CO2} Same k as rxn BR27
BR49 MACO3 + NO2 = MAPAN Same k as rxn BR28 BR50 MAPAN = MACO3 + NO2 4.79e-4 1.60e+16 26.80 BR51 MACO3 + NO = NO2 + CO2 + HCHO + MECO3 Same k as rxn BR30 BR52 MACO3 + HO2 = RCOOH + #.75 O2 + #.25 O3 + XC Same k as rxn BR22

BR53 MACO3 + NO3 = NO2 + CO2 + HCHO + MECO3 + O2 Same k as rxn BR09

BR54 MACO3 + MEO2 = RCOOH + HCHO + XC + O2 Same k as rxn BR24 BR55 MACO3 + RO2C = RCOOH + XC Same k as rxn BR25 BR56 MACO3 + RO2XC = RCOOH + O2 + XC Same k as rxn BR25

BR57 MACO3 + MECO3 = #2 CO2 + MEO2 + HCHO + MECO3 + O2 Same k as rxn BR27

BR58 MACO3 + RCO3 = HCHO + MECO3 + RO2C + xHO2 + yROOH + xCCHO + #2 CO2 Same k as rxn BR27

BR59 MACO3 + BZCO3 = HCHO + MECO3 + BZO + RO2C + #2 CO2 Same k as rxn BR27

BR60 MACO3 + MACO3 = #2 {HCHO + ME CO3 + CO2} Same k as rxn BR27 Other Organic Radical Species BR61 TBUO + NO2 = RNO3 + #-2 XC 2.40e-11 BR62 TBUO = ACET + MEO2 1.18e+3 7.50e+14 16.20
BR63 BZO + NO2 = NPHE 3.79e-11 2.30e-11 -0.30 BR64 BZO + HO2 = CRES + #-1 XC Same k as rxn BR08 BR65 BZO = CRES + RO2C + xHO2 + #-1 XC 1.00e-3 Steady-State Peroxy Radical operators (for form ation of inorganic and radical products) [c] RO01 xHO2 = HO2 k is variable parameter: RO2RO RO02 xHO2 = k is variable parameter: RO2XRO RO03 xOH = OH k is variable parameter: RO2RO RO04 xOH = k is variable parameter: RO2XRO RO05 xNO2 = NO2 k is variable parameter: RO2RO RO06 xNO2 = XN k is variable parameter: RO2XRO RO07 xMEO2 = MEO2 k is va riable parameter: RO2RO RO08 xMEO2 = XC k is vari able parameter: RO2XRO RO09 xMECO3 = MECO3 k is variable parameter: RO2RO RO10 xMECO3 = #2 XC k is va riable parameter: RO2XRO RO11 xRCO3 = RCO3 k is variable parameter: RO2RO RO12 xRCO3 = #3 XC k is va riable parameter: RO2XRO RO13 xMACO3 = MACO3 k is variable parameter: RO2ROTable A-2 (continued)

43 Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B

RO14 xMACO3 = #4 XC k is va riable parameter: RO2XRO RO15 xTBUO = TBUO k is variable parameter: RO2RO RO16 xTBUO = #4 XC k is va riable parameter: RO2XRO RO17 xCO = CO k is variable parameter: RO2RO RO18 xCO = XC k is vari able parameter: RO2XRO RO19 xHNO3 = HNO3 k is variable parameter: RO2RO RO20 xHNO3 = XN k is variable parameter: RO2XRO Explicit and Lumped Molecule Organic Products BP01 HCHO + HV = #2 HO2 + CO Phot Set= HCHOR-06 BP02 HCHO + HV = H2 + CO Phot Set= HCHOM-06 BP03 HCHO + OH = HO2 + CO + H2O 8.47e-12 5.40e-12 -0.27 BP07 HCHO + NO3 = HNO3 + HO2 + CO 6.06e-16 2.00e-12 4.83
BP08 CCHO + OH = MECO3 + H2O 1.49e-11 4.40e-12 -0.73 BP09 CCHO + HV = CO + HO2 + MEO2 Phot Set= CCHO_R BP10 CCHO + NO3 = HNO3 + MECO3 2.84e-15 1.40e-12 3.70

BP11 RCHO + OH = #.965 RCO3 + #.035 {RO2C + xHO2 + xCO + xCCHO + yROOH} 1.97e-11 5.10e-12 -0.80

BP12 RCHO + HV = RO2C + xHO2 + yROOH + xCCHO + CO + HO2 Phot Set= C2CHO

BP13 RCHO + NO3 = HNO3 + RCO3 6.74e-15 1.40e-12 3.18 BP14 ACET + OH = RO2C + xMECO3 + xHCHO + yROOH 1.91e-13 4.56e-14 -0.85 3.65 BP15 ACET + HV = #.62 MECO3 + #1.38 MEO2 + #.38 CO Phot Set= ACET-06, qy= 0.5

BP16 MEK + OH = #.967 RO2C + #.039 {RO2XC + zRNO3} + #.376 xHO2 + #.51 xMECO3 + #.074 xRCO3 + #.088 xHCHO + #.504 xCCHO + #.376 xRCHO + yROOH + #.3 XC 1.20e-12 1.30e-12 0.05 2.00

BP17 MEK + HV = MECO3 + RO2C + xHO2 + xCCHO + yROOH Phot Set= MEK-06, qy= 0.175

BP18 MEOH + OH = HCHO + HO2 9.02e-13 2.85e-12 0.69 BP19 HCOOH + OH = HO2 + CO2 4.50e-13

BP20 CCOOH + OH = #.509 MEO2 + #.491 RO2C + #.509 CO2 + #.491 xHO2 + #.491 xMGLY + #.491 yROOH + #-0.491 XC 7.26e-13 4.20e-14 -1.70

BP21 RCOOH + OH = RO2C + #.08 CO2 + xHO2 + #.063 CO2 + #.142 xCCHO + #.4 xRCHO + #.457 xBACL + yROOH + #-0.455 XC 1.20e-12

BP22 COOH + OH = H2O + #.3 {HCHO + OH} + #.7 MEO2 7.40e-12 3.80e-12 -0.40 BP23 COOH + HV = HCHO + HO2 + OH Phot Set= COOH

BP24 ROOH + OH = #.744 OH + #.251 RO2C + #.004 RO2XC + #.004 zRNO3 + #.744 RCHO + #.239 xHO2 + #.012 xOH + #.012 xHCHO + #.012 xCCHO + #.205 xRCHO + #.034 xPROD2 + #.256 yROOH + #-0.115 XC 2.50e-11

BP25 ROOH + HV = RCHO + HO2 + OH Phot Set= COOHTable A-2 (continued)

44 Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B

BP26 R6OOH + OH = #.84 OH + #.222 RO2C + #.029 RO2XC + #.029 zRNO3 + #.84 PROD2 + #.09 xHO2 + #.041 xOH + #.02 xCCHO + #.075 xRCHO + #.084 xPROD2 + #.16 yROOH + #.02 XC 5.60e-11

BP27 R6OOH + HV = OH + #.142 HO2 + #.782 RO2C + #.077 RO2XC + #.077 zRNO3 + #.085 RCHO + #.142 PROD2 + #.782 xHO2 + #.026 xCCHO + #.058 xRCHO + #.698 xPROD2 + #.858 yR6OOH + #.017 XC Phot Set= COOH

BP28 RAOOH + OH = #.139 OH + #.148 HO2 + #.589 RO2C + #.124 RO2XC + #.124 zRNO3 + #.074 PROD2 + #.147 MGLY + #.139 IPRD + #.565 xHO2 + #.024 xOH + #.448 xRCHO + #.026 xGLY + #.030 xMEK + #.252 xMGLY + #.073 xAFG1 + #.073 xAFG2 + #.713 yR6OOH + #2.674 XC 1.41e-10

BP29 RAOOH + HV = OH + HO2 + #.5 {GLY + MGLY + AFG1 + AFG2} + #.5 XC Phot Set= COOH

BP30 GLY + HV = #2 {CO + HO2} Phot Set= GLY-07R BP31 GLY + HV = HCHO + CO Phot Set= GLY-07M

BP32 GLY + OH = #.63 HO2 + #1.26 CO + #.37 RCO3 + #- .37 XC 1.10e-11

BP33 GLY + NO3 = HNO3 + #.63 HO2 + #1.26 CO + #.37 RCO3 + #-.37 XC 1.02e-15 2.80e-12 4.72

BP34 MGLY + HV = HO2 + CO + MECO3 Phot Set= MGLY-06 BP35 MGLY + OH = CO + MECO3 1.50e-11 BP36 MGLY + NO3 = HNO3 + CO + MECO3 2.53e-15 1.40e-12 3.77
BP37 BACL + HV = #2 MECO3 Phot Set= BACL-07

BP38 CRES + OH = #.2 BZO + #.8 {RO2C + xHO2 + yR6OOH} + #.25 xMGLY + #5.05 XC 4.03e-11 1.70e-12 -1.89

BP39 CRES + NO3 = HNO3 + BZO + XC 1.40e-11
BP40 NPHE + OH = BZO + XN 3.50e-12 BP41 NPHE + HV = HONO + #6 XC Phot Set= NO2-06, qy= 1.5e-3 BP42 NPHE + HV = #6 XC + XN Phot Set= NO2-06, qy= 1.5e-2
BP43 BALD + OH = BZCO3 1.20e-11 BP44 BALD + HV = #7 XC Phot Set= BALD-06, qy= 0.06 BP45 BALD + NO3 = HNO3 + BZCO3 2.73e-15 1.34e-12 3.70Table A-2 (continued)

45 Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B

Lumped Unsaturated Aromatic Ring-Opening Products

BP46 AFG1 + OH = #.217 MACO3 + #.723 RO2C + #.060 {RO2XC + zRNO3} + #.060 zRNO3 + #.521 xHO2 + #.201 xMECO3 + #.334 xCO + #.407 xRCHO + #.129 xMEK + #.107 xGLY + #.267 xMGLY + #.783 yR6OOH + #-.076 XC 7.40e-11

BP47 AFG1 + O3 = #.826 OH + #.522 HO2 + #.652 RO2C + #.522 CO + #.174 CO2 + #.432 GLY + #.568 MGLY + #.652 xRCO3 + #.652 xHCHO + #.652 yR6OOH + #- .872 XC 9.66e-18

BP48 AFG1 + HV = #1.023 HO2 + #.173 MEO2 + #.305 MECO3 + #.500 MACO3 + #.695 CO + #.195 GLY + #.305 MGLY + #.217 XC Phot Set= AFG1

BP49 AFG2 + OH = #.217 MACO3 + #.723 RO2C + #.060 {RO2XC + zRNO3} + #.060 zRNO3 + #.521 xHO2 + #.201 xMECO3 + #.334 xCO + #.407 xRCHO + #.129 xMEK + #.107 xGLY + #.267 xMGLY + #.783 yR6OOH + #-.076 XC 7.40e-11

BP50 AFG2 + O3 = #.826 OH + #.522 HO2 + #.652 RO2C + #.522 CO + #.174 CO2 + #.432 GLY + #.568 MGLY + #.652 xRCO3 + #.652 xHCHO + #.652 yR6OOH + #- .872 XC 9.66e-18

BP51 AFG2 + HV = PROD2 + #-1 XC Phot Set= AFG1

BP52 AFG3 + OH = #.206 MACO3 + #.733 RO2C + #.117 {RO2XC + zRNO3} + #.117 zRNO3 + #.561 xHO2 + #.117 xMECO3 + #.114 xCO + #.274 xGLY + #.153 xMGLY + #.019 xBACL + #.195 xAFG1 + #.195 xAFG2 + #.231 xIPRD + #.794 yR6OOH + #.236 XC 9.35e-11

BP53 AFG3 + O3 = #.471 OH + #.554 HO2 + #.013 MECO3 + #.258 RO2C + #.007 {RO2XC + zRNO3} + #.007 zRNO3 + #.580 CO + #.190 CO2 + #.366 GLY + #.184 MGLY + #.350 AFG1 + #.350 AFG2 + #.139 AFG3 + #.003 MACR + #.004 MVK + #.003 IPRD + #.095 xHO2 + #.163 xRCO3 + #.163 xHCHO + #.095 xMGLY + #.264 yR6OOH + #-.617 XC 1.43e-17

BP54 MACR + OH = #.5 MACO3 + #.5 {RO2C + xHO2} + #.416 xCO + #.084 xHCHO + #.416 xMEK + #.084 xMGLY + #.5 yROOH + #-0.416 XC 2.84e-11 8.00e-12 -0.76

BP55 MACR + O3 = #.208 OH + #.108 HO2 + #.1 RO2C + #.45 CO + #.117 CO2 + #.1 HCHO + #.9 MGLY + #.333 HCOOH + #.1 xRCO3 + #.1 xHCHO + #.1 yROOH + #-0.1 XC 1.28e-18 1.40e-15 4.17

BP56 MACR + NO3 = #.5 {MACO3 + RO2C + HNO3 + xHO2 + xCO} + #.5 yROOH + #1.5 XC + #.5 XN 3.54e-15 1.50e-12 3.61

BP57 MACR + O3P = RCHO + XC 6.34e-12Table A-2 (continued)

46 Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B

BP58 MACR + HV = #.33 OH + #.67 HO2 + #.34 MECO3 + #.33 MACO3 + #.33 RO2C + #.67 CO + #.34 HCHO + #.33 xMECO3 + #.33 xHCHO + #.33 yROOH Phot Set= MACR-06

BP59 MVK + OH = #.975 RO2C + #.025 {RO2XC + zRNO3} + #.3 xHO2 + #.675 xMECO3 + #.3 xHCHO + #.675 xRCHO + #.3 xMGLY + yROOH + #-0.725 XC 1.99e-11 2.60e-12 -1.21

BP60 MVK + O3 = #.164 OH + #.064 HO2 + #.05 {RO2C + xHO2} + #.475 CO + #.124 CO2 + #.05 HCHO + #.95 MGLY + #.351 HCOOH + #.05 xRCO3 + #.05 xHCHO + #.05 yROOH + #-0.05 XC 5.36e-18 8.50e-16 3.02

BP61 MVK + NO3 = #4 XC + XN (Slow) BP62 MVK + O3P = #.45 RCHO + #.55 MEK + #.45 XC 4.32e-12

BP63 MVK + HV = #.4 MEO2 + #.6 CO + #.6 PROD2 + #.4 MACO3 + #-2.2 XC Phot Set= MVK-06

BP64 IPRD + OH = #.289 MACO3 + #.67 {RO2C + xHO2} + #.041 {RO2XC + zRNO3} + #.336 xCO + #.055 xHCHO + #.129 xCCHO + #.013 xRCHO + #.15 xMEK + #.332 xPROD2 + #.15 xGLY + #.174 xMGLY + #-0.504 XC + #.711 yR6OOH 6.19e-11

BP65 IPRD + O3 = #.285 OH + #.4 HO2 + #.048 {RO2C + xRCO3} + #.498 CO + #.14 CO2 + #.124 HCHO + #.21 MEK + #.023 GLY + #.742 MGLY + #.1 HCOOH + #.372 RCOOH + #.047 xCCHO + #.001 xHCHO + #.048 yR6OOH + #-.329 XC 4.18e-18

BP66 IPRD + NO3 = #.15 {MACO3 + HNO3} + #.799 {RO2C + xHO2} + #.051 {RO2XC + zRNO3} + #.572 xCO + #.227 xHCHO + #.218 xRCHO + #.008 xMGLY + #.572 xRNO3 + #.85 yR6OOH + #.278 XN + #-.815 XC 1.00e-13

BP67 IPRD + HV = #1.233 HO2 + #.467 MECO3 + #.3 RCO3 + #1.233 CO + #.3 HCHO + #.467 CCHO + #.233 MEK + #-.233 XC Phot Set= MACR-06

Lumped Parameter Organic Products

BP68 PROD2 + OH = #.472 HO2 + #.473 RO2C + #.070 RO2XC + #.070 zRNO3 + #.002 HCHO + #.001 CCHO + #.143 RCHO + #.329 PROD2 + #.379 xHO2 + #.029 xMECO3 + #.049 xRCO3 + #.211 xHCHO + #.083 xCCHO + #.402 xRCHO + #.115 xMEK + #.007 xPROD2 + #.528 yR6OOH + #.883 XC 1.55e-11

BP69 PROD2 + HV = #.400 MECO3 + #.600 RCO3 + #1.590 RO2C + #.086 RO2XC + #.086 zRNO3 + #.914 xHO2 + #.303 xHCHO + #.163 xCCHO + #.780 xRCHO + yR6OOH + #-.085 XC Phot Set= MEK-06, qy= 4.86e-3Table A-2 (continued)

47 Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B

BP70 RNO3 + OH = #.019 NO2 + #.189 HO2 + #.976 RO2C + #.175 RO2XC + #.175 zRNO3 + #.001 RCHO + #.010 MEK + #.007 PROD2 + #.189 RNO3 + #.312 xNO2 + #.305 xHO2 + #.011 xHCHO + #.428 xCCHO + #.036 xRCHO + #.004 xACET + #.170 xMEK + #.030 xPROD2 + #.305 xRNO3 + #.792 yR6OOH + #.175 XN + #.054 XC 7.20e-12

BP71 RNO3 + HV = NO2 + #.344 HO2 + #.721 RO2C + #.102 RO2XC + #.102 zRNO3 + #.074 HCHO + #.214 CCHO + #.074 RCHO + #.124 MEK + #.190 PROD2 + #.554 xHO2 + #.061 xHCHO + #.230 xCCHO + #.063 xRCHO + #.008 xACET + #.083 xMEK + #.261 xPROD2 + #.656 yR6OOH + #.396 XC Phot Set= IC3ONO2

Steady-State Peroxy Radical operators (for form ation of organic product species formed in peroxy + NO reactions) [c] PO01 xHCHO = HCHO k is variable parameter: RO2RO PO02 xHCHO = XC k is vari able parameter: RO2XRO PO03 xCCHO = CCHO k is variable parameter: RO2RO PO04 xCCHO = #2 XC k is va riable parameter: RO2XRO PO05 xRCHO = RCHO k is variable parameter: RO2RO PO06 xRCHO = #3 XC k is va riable parameter: RO2XRO PO07 xACET = ACET k is va riable parameter: RO2RO PO08 xACET = #3 XC k is va riable parameter: RO2XRO PO09 xMEK = MEK k is variable parameter: RO2RO PO10 xMEK = #4 XC k is va riable parameter: RO2XRO PO11 xPROD2 = PROD2 k is variable parameter: RO2RO PO12 xPROD2 = #6 XC k is va riable parameter: RO2XRO PO13 xGLY = GLY k is va riable parameter: RO2RO PO14 xGLY = #2 XC k is va riable parameter: RO2XRO PO15 xMGLY = MGLY k is variable parameter: RO2RO PO16 xMGLY = #3 XC k is va riable parameter: RO2XRO PO17 xBACL = BACL k is va riable parameter: RO2RO PO18 xBACL = #4 XC k is va riable parameter: RO2XRO PO19 xBALD = BALD k is va riable parameter: RO2RO PO20 xBALD = #7 XC k is va riable parameter: RO2XRO PO21 xAFG1 = AFG1 k is va riable parameter: RO2RO PO22 xAFG1 = #5 XC k is va riable parameter: RO2XRO PO23 xAFG2 = AFG2 k is va riable parameter: RO2RO PO24 xAFG2 = #5 XC k is va riable parameter: RO2XRO PO25 xAFG3 = AFG3 k is va riable parameter: RO2RO PO26 xAFG3 = #7 XC k is va riable parameter: RO2XRO PO27 xMACR = MACR k is va riable parameter: RO2RO PO28 xMACR = #4 XC k is va riable parameter: RO2XRO PO29 xMVK = MVK k is variable parameter: RO2RO PO30 xMVK = #4 XC k is vari able parameter: RO2XRO PO31 xIPRD = IPRD k is va riable parameter: RO2RO PO32 xIPRD = #5 XC k is va riable parameter: RO2XROTable A-2 (continued)

48 Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B PO33 xRNO3 = RNO3 k is variable parameter: RO2RO PO34 xRNO3 = #6 XC + XN k is variable parameter: RO2XRO PO35 xHCOOH = HCOOH k is variable parameter: RO2RO PO36 xHCOOH = XC k is va riable parameter: RO2XRO PO37 xCCOOH = CCOOH k is variable parameter: RO2RO PO38 xCCOOH = #2 XC k is variable parameter: RO2XRO PO39 xRCOOH = RCOOH k is variable parameter: RO2RO PO40 xRCOOH = #3 XC k is variable parameter: RO2XRO Steady-State Peroxy Radical operators (for formatio n of organic nitrates formed in peroxy + NO reactions) [d] PO41 zRNO3 = RNO3 + #-1 XN k is variable parameter: RO2NO PO42 zRNO3 = PROD2 + HO2 k is variable parameter: RO22NN PO43 zRNO3 = #6 XC k is va riable parameter: RO2XRO Steady-State Peroxy Radical operators (for forma tion of hydroperoxides formed in peroxy + HO 2 reactions) [e] PO44 yROOH = ROOH + #-3 XC k is variable parameter: RO2HO2 PO45 yROOH = MEK + #-4 XC k is variable parameter: RO2RO2M PO46 yROOH = k is variable parameter: RO2RO PO47 yR6OOH = R6OOH + #-6 XC k is variable parameter: RO2HO2 PO48 yR6OOH = PROD2 + #-6 XC k is variable parameter: RO2RO2M PO49 yR6OOH = k is variable parameter: RO2RO PO50 yRAOOH = RAOOH + #-8 XC k is variable parameter: RO2HO2 PO51 yRAOOH = PROD2 + #-6 XC k is variable parameter: RO2RO2M PO52 yRAOOH = k is variable parameter: RO2RO Explicitly Represented Primary Organics BE01 CH4 + OH = H2O + MEO2 6.62e-15 1.85e-12 3.36 BE02 8.15e-12 Falloff, F=0.60, N=1.00 0: 1.00e-28 0.00 -4.50 ETHENE + OH = RO2C + xHO2 + #1.61 xHCHO + #.195 xCCHO + yROOH inf: 8.80e-12 0.00 -0.85 BE03 ETHENE + O3 = #.16 OH + #.16 HO2 + #.51 CO + #.12 CO2 + HCHO + #.37 HCOOH 1.68e-18 9.14e-15 5.13

BE04 ETHENE + NO3 = RO2C + xHO2 + xRCHO + yROOH + #-1 XC + XN 2.24e-16 3.30e-12 5.72 2.00

BE05 ETHENE + O3P = #.8 HO2 + #.51 MEO2 + #.29 RO2C + #.51 CO + #.1 CCHO + #.29 xHO2 + #.278 xCO + #.278 xHCHO + #.012 xGLY + #.29 yROOH + #.2 XC 7.43e-13 1.07e-11 1.59

BE06 ISOPRENE + OH = #.986 RO2C + #.093 {RO2XC + zRNO3} + #.907 xHO2 + #.624 xHCHO + #.23 xMACR + #.32 xMVK + #.357 xIPRD + yR6OOH + #- 0.167 XC 9.96e-11 2.54e-11 -0.81

BE07 ISOPRENE + O3 = #.266 OH + #.066 HO2 + #.192 RO2C + #.008 {RO2XC + zRNO3} + #.275 CO + #.122 CO2 + #.4 HCHO + #.1 PROD2 + #.39 MACR + #.16 MVK + #.15 IPRD + #.204 HCOOH + #.192 {xMACO3 + xHCHO} + #.2 yR6OOH + #-0.559 XC 1.34e-17 7.86e-15 3.80Table A-2 (continued)

49 Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B BE08 ISOPRENE + NO3 = #.936 RO2C + #.064 {RO2XC + zRNO3} + #.749 xHO2 + #.187 xNO2 + #.936 xIPRD + yR6OOH + #-0.064 XC + #.813 XN 6.81e-13 3.03e-12 0.89

BE09 ISOPRENE + O3P = #.25 MEO2 + #.24 RO2C + #.01 {RO2XC + zRNO3} + #.75 PROD2 + #.24 xMACO3 + #.24 xHCHO + #.25 yR6OOH + #-1.01 XC 3.50e-11

BE10 ACETYLEN + OH = #.7 OH + #.3 HO2 + #.3 CO + #.7 GLY + #.3 HCOOH 7.56e-13 Falloff, F=0.60, N=1.00

BE11 ACETYLEN + O3 = #.5 OH + #1.5 HO2 + #1.5 CO + #.5 CO2 1.16e-20 1.00e-14 8.15

BE12 BENZENE + OH = #.116 OH + #.29 {RO2C + xHO2} + #.024 {RO2XC + zRNO3} + #.57 {HO2 + CRES} + #.116 AFG3 + #.290 xGLY + #.029 xAFG1 + #.261 xAFG2 + #.314 yRAOOH + #-.976 XC 1.22e-12 2.33e-12 0.38

Reactions of Compounds represented ex plicitly in the chamber simulations

CH05 N-C4 + OH = #1.334 RO2C + #.079 RO2XC + #.079 zRNO3 + #.921 xHO2 + #.632 xCCHO + #.120 xRCHO + #.485 xMEK + yROOH + #-.038 XC 2.38e-12 1.63e-12 -0.23

CH07 N-C6 + OH = #1.562 RO2C + #.225 RO2XC + #.225 zRNO3 + #.775 xHO2 + #.011 xCCHO + #.113 xRCHO + #.688 xPROD2 + yR6OOH + #.161 XC 5.25e-12 7.62e-12 0.22

CH09 N-C8 + OH = #1.432 RO2C + #.354 RO2XC + #.354 zRNO3 + #.646 xHO2 + #.024 xRCHO + #.622 xPROD2 + yR6OOH + #2.072 XC 8.16e-12 2.45e-12 -0.72

CH11 PROPENE + OH = #.984 RO2C + #.016 RO2XC + #.016 zRNO3 + #.984 xHO2 + #.984 xHCHO + #.984 xCCHO + yROOH + #-.048 XC 2.60e-11 4.85e-12 -1.00

CH12 PROPENE + O3 = #.350 OH + #.165 HO2 + #.355 MEO2 + #.525 CO + #.215 CO2 + #.500 HCHO + #.500 CCHO + #.185 HCOOH + #.075 CCOOH + #.070 XC 1.05e-17 5.51e-15 3.73

CH13 PROPENE + NO3 = #.949 RO2C + #.051 RO2XC + #.051 zRNO3 + #.949 xHO2 + yROOH + #2.694 XC + XN 9.73e-15 4.59e-13 2.30

CH14 PROPENE + O3P = #.450 RCHO + #.550 MEK + #- .550 XC 4.01e-12 1.02e-11 0.56

CH16 T-2-BUTE + OH = #.965 RO2C + #.035 RO2XC + #.035 zRNO3 + #.965 xHO2 + #1.930 xCCHO + yROOH + #-.070 XC 6.32e-11 1.01e-11 -1.09

CH17 T-2-BUTE + O3 = #.540 OH + #.170 HO2 + #.710 MEO2 + #.540 CO + #.310 CO2 + CCHO + #.150 CCOOH + #.140 XC 1.95e-16 6.64e-15 2.10

CH18 T-2-BUTE + NO3 = #.920 RO2C + #.080 RO2XC + #.080 zRNO3 + #.705 xNO2 + #.215 xHO2 + #1.410 xCCHO + #.215 xRNO3 + yROOH + #-.590 XC + #.080 XN 3.93e-13 1.10e-13 -0.76

CH19 T-2-BUTE + O3P = MEK 1.99e-11 1.09e-11 -0.36Table A-2 (continued)

50 Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B CH21 TOLUENE + OH = #.312 {OH + AFG3} + #.181 {HO2 + CRES} + #.454 {RO2C + xHO2} + #.054 {RO2XC +zRNO3} + #.238 xGLY + #.151 xMGLY + #.065 xBALD + #.195 xAFG1 + #.195 xAFG2 + #.073 yR6OOH + #.435 yRAOOH + #-.109 XC 5.58e-12 1.81e-12 -0.67

CH23 M-XYLENE + OH = #.239 {OH + AFG3} + #.159 {HO2 + CRES} + #.52 {RO2C +xHO2} + #.082 {RO2XC + zRNO3} + #.100 xGLY + #.380 xMGLY + #.041 xBALD + #.336 xAFG1 + #.144 xAFG2 + #.047 yR6OOH + #.555 yRAOOH+ #.695 XC 2.31e-11

Reactions of Ethane used in its Atmospheric Reactivity Simulations C201 ETHANE + OH = RO2C + xHO2 + xCCHO + yROOH 2.54E-13 1.34E-12 0.992 2.0 Reactions of Lumped Species used in Atmospheric Reactivity Simulations BL01 ALK1 + OH = RO2C + xHO2 + xCCHO + yROOH 2.54e-13 1.34e-12 0.99

BL02 ALK2 + OH = #.965 RO2C + #.035 {RO2XC + zRNO3} + #.965 xHO2 + #.261 xRCHO + #.704 xACET + yROOH + #-.105 XC 1.11e-12 1.49e-12 0.17

BL03 ALK3 + OH = #1.253 RO2C + #.07 {RO2XC + zRNO3} + #.694 xHO2 + #.236 xTBUO + #.026 xHCHO + #.445 xCCHO + #.122 xRCHO + #.024 xACET + #.332 xMEK + yROOH + #-.046 XC 2.31e-12 1.51e-12 -0.25

BL04 ALK4 + OH = #1.773 RO2C + #.144 {RO2XC + zRNO3} + #.834 xHO2 + #.011 xMEO2 + #.011 xMECO3 + #.002 xCO + #.030 xHCHO + #.454 xCCHO + #.242 xRCHO + #.442 xACET + #.110 xMEK + #.128 xPROD2 + yR6OOH + #-.097 XC 4.26e-12 3.67e-12 -0.09

BL05 ALK5 + OH = #1.597 RO2C + #.348 {RO2XC + zRNO3} + #.652 xHO2 + #.037 xHCHO + #.099 xCCHO + #.199 xRCHO + #.066 xACET + #.080 xMEK + #.425 xPROD2 + yR6OOH + #2.012 XC 9.22e-12 2.65e-12 -0.74

BL06 OLE1 + OH = #1.138 RO2C + #.095 {RO2XC + zRNO3} + #.904 xHO2 + #.001 xMEO2 + #.700 xHCHO + #.301 xCCHO + #.470 xRCHO + #.005 xACET + #.119 xPROD2 + #.026 xMACR + #.008 xMVK + #.006 xIPRD + yROOH + #.822 XC 3.29e-11 6.18e-12 -1.00

BL07 OLE1 + O3 = #.193 OH + #.116 HO2 + #.104 MEO2 + #.063 RO2C + #.004 {RO2XC + zRNO3} + #.368 CO + #.125 CO2 + #.500 HCHO + #.147 CCHO + #.353 RCHO + #.006 MEK + #.189 PROD2 + #.185 HCOOH + #.022 CCOOH + #.112 RCOOH + #.040 xHO2 + #.007 xCCHO + #.031 xRCHO + #.002 xACET + #.044 yR6OOH + #.69 XC 1.09e-17 3.15e-15 3.38

BL08 OLE1 + NO3 = #1.312 RO2C + #.176 {RO2XC + zRNO3} + #.824 xHO2 + #.009 xCCHO + #.002 xRCHO + #.024 xACET + #.546 xRNO3 + yR6OOH + #.454 XN + #.572 XC 1.44e-14 4.73e-13 2.08Table A-2 (continued)

51 Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B

BL09 OLE1 + O3P = #.450 RCHO + #.437 MEK + #.113 PROD2 + #1.224 XC 5.02e-12 1.49e-11 0.65

BL10 OLE2 + OH = #.966 RO2C + #.086 {RO2XC + zRNO3} + #.914 xHO2 + #.209 xHCHO + #.787 xCCHO + #.483 xRCHO + #.136 xACET + #.076 xMEK + #.021 xPROD2 + #.027 xMACR + #.002 xMVK + #.037 xIPRD + yR6OOH + #.113 XC 6.41e-11 1.26e-11 -0.97

BL11 OLE2 + O3 = #.421 OH + #.093 HO2 + #.290 MEO2 + #.199 RO2C + #.003 {RO2XC + zRNO3} + #.296 CO + #.162 CO2 + #.152 HCHO + #.426 CCHO + #.316 RCHO + #.048 ACET + #.031 MEK + #.042 PROD2 + #.028 MACR + #.021 MVK + #.033 HCOOH + #.061 CCOOH + #.222 RCOOH + #.039 xHO2 + #.147 xMECO3 + #.007 xRCO3 + #.108 xHCHO + #.066 xCCHO + #.019 xRCHO + #.196 yR6OOH + #.133 XC 1.24e-16 8.15e-15 2.49

BL12 OLE2 + NO3 = #1.185 RO2C + #.136 {RO2XC + zRNO3} + #.409 xNO2 + #.423 xHO2 + #.033 xMEO2 + #.074 xHCHO + #.546 xCCHO + #.153 xRCHO + #.110 xACET + #.002 xMEK + #.026 xMVK + #.007 xIPRD + #.322 xRNO3 + yR6OOH + #.270 XN + #.117 XC 7.70e-13 2.15e-13 -0.76

BL13 OLE2 + O3P = #.014 HO2 + #.013 RO2C + #.074 RCHO + #.709 MEK + #.203 PROD2 + #.007 xHO2 + #.007 xMACO3 + #.006 xCO + #.006 xMACR + #.014 yR6OOH + #.666 XC 2.06e-11 1.43e-11 -0.22

BL14 ARO1 + OH = #.283 OH + #.166 HO2 + #.483 RO2C + #.068 {RO2XC + zRNO3} + #.166 CRES + #.283 AFG3 + #.483 xHO2 + #.217 xGLY + #.138 xMGLY + #.049 xBALD + #.079 xPROD2 + #.164 xAFG1 + #.192 xAFG2 + #.150 yR6OOH + #.402 yRAOOH+ #.004 XC 6.18e-12

BL15 ARO2 + OH = #.199 OH + #.108 HO2 + #.582 RO2C + #.111 RO2XC + #.111 zRNO3 + #.108 CRES + #.199 AFG3 + #.582 xHO2 + #.111 xGLY + #.291 xMGLY + #.104 xBACL + #.033 xBALD + #.042 xPROD2 + #.223 xAFG1 + #.211 xAFG2 + #.074 xAFG3 + #.090 yR6OOH + #.603 yRAOOH+ #1.503 XC 2.20e-11

BL16 TERP + OH = #1.147 RO2C + #.2 {RO2XC + zRNO3} + #.759 xHO2 + #.042 xRCO3 + #.002 xCO + #.264 xHCHO + #.533 xRCHO + #.036 xACET + #.005 xMEK + #.255 xPROD2 + #.009 xMGLY + #.014 xBACL + #.002 xMVK + #.001 xIPRD + yR6OOH + #5.055 XC 7.98e-11 1.87e-11 -0.86Table A-2 (continued)

52 Rate Parameters [b]

Label Reaction and Products [a] k(300) A Ea B

BL17 TERP + O3 = #.585 OH + #.052 HO2 + #.875 RO2C + #.203 RO2XC + #.203 zRNO3 + #.166 CO + #.045 CO2 + #.079 HCHO + #.004 MEK + #.409 PROD2 + #.107 HCOOH + #.043 RCOOH + #.067 xHO2 + #.126 xMECO3 + #.149 xRCO3 + #.019 xCO + #.150 xHCHO + #.220 xRCHO + #.165 xACET + #.001 xGLY + #.002 xMGLY + #.055 xBACL + #.001 xMACR + #.001 xIPRD + #.545 yR6OOH + #3.526 XC 6.99e-17 1.02e-15 1.60

BL18 TERP + NO3 = #1.508 RO2C + #.397 RO2XC + #.397 zRNO3 + #.422 xNO2 + #.162 xHO2 + #.019 xRCO3 + #.010 xCO + #.017 xHCHO + #.001 xCCHO + #.509 xRCHO + #.174 xACET + #.001 xMGLY + #.003 xMACR + #.001 xMVK + #.002 xIPRD + #.163 xRNO3 + yR6OOH + #4.476 XC + #.415 XN 6.53e-12 1.28e-12 -0.97

BL19 TERP + O3P = #.147 RCHO + #.853 PROD2 + #4.441 XC 3.71e-11

[a] Format of reaction listing: “=“ separates reactants from products; “# number ” indicates stoichiometric coefficient, “# coefficient {

product list }” means that the stoichiometric coefficient is applied to all the products listed. [b] Except as indicated, the rate constants are given by k(T) = A · (T/300) B · e -Ea/RT , where the units of k and A are cm 3 molec -1 s -1 , Ea are kcal mol -1 , T is o K, and R=0.0019872 kcal mol -1 deg -1 . If A, Ea, and B are not given the rate constants are assumed to be temperature independent. The following special rate constant expressions are used:
Phot Set = name : The absorption cross sections and (if applicable) quantum yields for the photolysis

reaction are given by Carter (2009). Here, “ name ” indicates the photolysis set used. If a “qy= number ” notation is given, the number given is the overall quantum yield, which is assumed to be wavelength independent. Photolys is rates used in chamber and am bient simulations are given in Table A-3.
Falloff : The rate constant as a function of temperat ure and pressure is calculated using k(T,M) = {k0(T)·[M]/[1 + k0(T)·[M]/kinf(T)]}· F Z , where Z = {1 + [log10{k0(T)·[M])/kinf(T)}/N] 2 } -1 , [M] is the total pressure in molecules cm -3 , F and N are as indicated on the table, and the temperature dependences of k0 and kinf are as indicated on the table. k = k0+k3M(1+k3M/k2): The rate constant as a function of te mperature and pressure is calculated

using k(T,M) = k0(T) + k3(T)·[M] ·(1 + k3(T)·[M]/ k2(T)), where [M] is the total bath gas (air) concentration in molecules cm-3, and the temp erature dependences for k0, k2 and k3 are as indicated on the table. k = k1 + k2 [M]: The rate constant as a function of temp erature and pressure is calculated using

k(T,M) = k1(T) + k2(T)·[M], where [M] is the total bath gas (air) concentration in molecules cm-3, and the temperature dependences for k1, and k2 are as indicated on the table.
Same K as Rxn xx : Uses the same rate constant as the reac tion in the base mechanism with the same

label. k is variable parameter name : The rate constant is calculated us ing variable parameters that are

calculated using concentrations of various speci es. See Footnotes [c], [d], and [e], below. [c] The xPROD chemical operator sp ecies are used to repr esent the formation of radicals and products from alkoxy radicals formed in the reactions of peroxy radicals with NO, NO 3 , and other peroxyTable A-2 (continued)

53 radicals. These products are not formed when peroxy radicals react with HO 2 and acyl peroxy radicals, since those reactions are assumed not form alkoxy radicals, but instead form hydroperoxides or H-shift disproportion products th at are represented by separate yROOH chemical operator species, discussed in a separate footnote. Th e reactions of peroxy radicals with other peroxy radicals are assumed to form alkoxy radicals 50% of the time, so the products from alkoxy radical reactions are represented as being formed in 50% yields in these reactions. The consumption and products formed from these species can be represen ted in several ways. The most straightforward method is to include a reaction for each of the types of peroxy radical reactions, as follows:
xPROD + NO → NO + PROD xPROD + HO2 → HO2 xPROD + NO3 → NO3 + PROD xPROD + MECO3 → MECO3 (& similar reactions for RCO3, BZCO3, and MACO3) xPROD + RO2C → RO2C + 1/2 PROD (& a similar reaction for RO2XC) where "PROD" represents the product species fo r the operator (e.g, HO2 for xHO2). The rate constants for these reactions should be the same as the rate constant for the corresponding reactions of RO2C or RO2XC. This is a somewhat cumb ersome method because it requires 9 reactions for each of the many xPROD species. An alternative method, implemented in this table, uses the coefficient "RO2RO" to determine the rate of fo rmation of the product species and "RO2XRO" to represent processes where the product is not form ed. These are calculated as follows, where the k(RO2+..)'s refer to the rate constants for the reactions of RO2C or RO2XC with the indicated
reactant. RO2RO = k(RO2+NO)[NO] + k(RO2+NO3)[NO3] + 0.5 k(RO2+MEO2)[MEO2] + 0.5 k(RO2+RO2){[RO2C]+[RO2XC]) RO2XRO = k(RO2+HO2)[HO2] + k(RO 2+MECO3){[MECO3]+[RCO3]+[BZCO3]+ [MACO3]) + 0.5 k(RO2+MEO2)[MEO2] + 0.5 k(RO2+RO2){[RO2C]+ [RO2XC]) The steady state approximation must be used for these operators wh en this representation is used, and the operators must not be allowe d to be diluted or transported. [d] The zRNO3 chemical operator species is used to represent the formation organic nitrates formed when peroxy radicals react with NO, or formation of of radicals and products from alkoxy radicals formed in the reactions of peroxy radicals with NO 3 and other peroxy radicals. These products are not formed when peroxy radicals react with HO 2 and acyl peroxy radicals, since those reactions are assumed not form organic nitrates or alkoxy radicals, but instead form hydroperoxides or H-shift disproportion products that are represented by se parate yROOH chemical operator species, discussed in a separate footnote. At present the mechanis m has only one zRNO3 operator to correspond to the single lumped organic nitrate model species, but othe r such operators can be added if it is desired to have separate organic nitrate model species, such as, for example, those to represent semi-volatile organic nitrates that may contribute to SOA. In the case of zRNO3, the products resulting if alkoxy radicals are formed in the RCO3 or RO2 reactions would depend on reactant and individual radicals, and are approximated by PROD2 and HO2 (as might occur following the reaction of a peroxy radical with O2 to form HO2 and a ketone species). As with the xPROD species, the consumption and products formed from these species can be re presented in several ways, with the most straightforward method being to include a reaction fo r each of the types of peroxy radical reactions, as follows:
zRNO3 + NO → NO + RNO3 zRNO3 + HO2 → HO2 zRNO3 + NO3 → NO3 + PROD2 + HO2 zRNO3 + MECO3 → MECO3 (& similar reactions for RCO3, BZCO3, and MACO3) zRNO3 + RO2C → RO2C + 1/2 {PROD2 + HO2} (& a similar reaction for RO2XC)Table A-2 (continued)

54 The rate constants for these reactions should be th e same as the rate constant for the corresponding reactions of RO2C or RO2XC. As with xPROD, an alternative method, requiring fewer reactions, is implemented in this table. In this case, the coe fficient "RO2NO" is used to determine the rate of formation of organic nitrates, "RO22NN" is used to determine the rate of formation of the alkoxy radical products, and "RO2XRO" is used to repr esent processes where these products are is not formed, and is the same as used for xPROD. Thes e are calculated as follows, where the k(RO2+..)'s refer to the rate constants for the reactions of RO2C or RO2XC with the indicated reactant. RO2NO = k(RO2+NO)[NO] RO22NN = k(RO2+NO3)[NO3] + 0.5 k(RO2+MEO2)[MEO2] + 0.5 k(RO2+RO2){[RO2C]+ [RO2XC]) RO2XRO = k(RO2+HO2)[HO2] + k(RO 2+MECO3){[MECO3]+[RCO3]+[BZCO3]+ [MACO3]) + 0.5 k(RO2+MEO2)[MEO2] + 0.5 k(RO2+RO2){[RO2C]+ [RO2XC]) (same as used for xPROD) The steady state approximation must be used for these operators wh en this representation is used, and the operators must not be allowe d to be diluted or transported. [e] The yROOH chemical operator species is used to represent the formation of organic hydroperoxides formed with peroxy radicals react with HO 2 , or of H-shift disproportionation products formed when peroxy radicals react with acyl peroxy radicals or (in 50% yields) with other peroxy radicals. Note that the products formed when peroxy radicals react to form alkoxy radicals or organic nitrates (in the NO reaction) are represented using separate xP ROD or zRNO3 species, and together these three types of operators represent all the products a nd radicals formed. Separate such yROOH species are used to represent formation of hydroperoxides or H-shift disproportion products in different molecular weight ranges or volatilities, and more can be added as needed for appropriate predictions of SOA formation. The hydroperoxide formed in the HO2 reaction is represented by either ROOH, R6OOH, or RAOOH, and the H-shift disproportion products are represented by either MEK (for yROOH) or PROD2 (for the others). As with th e xPROD and zRNO3 species, the consumption and products formed from these species can be re presented in several ways, with the most straightforward method being to include a reaction fo r each of the types of peroxy radical reactions, as follows for yROOH (the reactions for the other two are analogous). yROOH + NO → NO yROOH + HO2 → HO2 + ROOH yROOH + NO3 → NO3 yROOH + MECO3 → MECO3 + MEK (& similar reactions for RCO3, BZCO3, and MACO3) yROOH + RO2C → RO2C + 1/2 MEK (& a similar reaction for RO2XC)
The rate constants for these reactions should be the same as the rate constant for the corresponding reactions of RO2C or RO2XC. As with the other operators, an alternative method, requiring fewer reactions, is implemented in this table. In this case, the coefficient "RO2HO2" is used to determine the rate of formation of organic hydroperoxides, "RO2RO2M" to determine th e rate of formation of H-shift disproportion products, and "RO2RO" is us ed to represent proces ses where these products are is not formed. Note that the latter is the same as the coefficient that is used to represent the formation products from the xPROD species. These are calculated as follows, where the k(RO2+..)'s refer to the rate constants for the reactions of RO2C or RO2XC with the indicated reactant. RO2HO2 = k(RO2+HO2)[HO2] RO2RO2M = k(RO2+MECO3){[MECO3]+[RCO3]+[BZCO3]+ [MACO3]) + 0.5 k(RO2+MEO2)[MEO2] + 0.5 k(RO2+RO2){[RO2C]+ [RO2XC])Table A-2 (continued)

55 RO2RO = k(RO2+NO)[NO] + k(RO2+NO3)[NO3] + 0.5 k(RO2+MEO2)[MEO2] + 0.5 k(RO2+RO2){[RO2C]+[RO2XC]) The steady state approximation must be used for th ese operators when this representation is used, and the operators must not be allowe d to be diluted or transported.

Table A-3. Summary of photolysis rates used in chamber and ambient simulations.

Photolysis rates (min-1) Ambient simulations (as function of solar zenith angle) [b] Phot File Cham b er [a] Z=0 Z=10 Z=20 Z=30 Z=40 Z= 50 Z=60 Z=70 Z=78 Z=86

Base Mechanism [c] NO2-06 0.115 0.723 0.718 0.702 0.676 0.631 0.560 0.430 0.253 0.093 0.005 NO3NO-06 2.44e-4 1.91e+0 1.91e+0 1.90e+0 1. 89e+0 1.87e+0 1.82e+0 1.65e+0 1.37e+0 9.15e-1 4.85e-1 NO3NO2-6 4.83e-2 1.54e+1 1.54e+1 1.53e+1 1. 52e+1 1.49e+1 1.44e+1 1.29e+1 1.03e+1 6.50e+0 2.80e+0 O3O1D-06 1.83e-4 3.06e-3 2.96e-3 2.68e-3 2.24e-3 1.67e-3 1.06e-3 4.91e-4 1.33e-4 2.01e-5 3.66e-7 O3O3P-06 4.84e-4 3.66e-2 3.66e-2 3.62e-2 3.57e-2 3.48e-2 3.32e-2 2.95e-2 2.37e-2 1.57e-2 8.36e-3 HONO-06 2.81e-2 1.14e-1 1.13e-1 1.10e-1 1.06e-1 9.78e-2 8.54e-2 6.38e-2 3.55e-2 1.18e-2 4.32e-4 HNO3 4.42e-6 5.40e-5 5.28e-5 4.91e-5 4.31e-5 3.49e-5 2.50e-5 1.40e-5 4.99e-6 9.91e-7 2.29e-8 HNO4-06 6.66e-5 5.42e-4 5.32e-4 5.01e-4 4.52e-4 3.81e-4 2.90e-4 1.77e-4 7.28e-5 1.70e-5 4.56e-7 H2O2 9.00e-5 5.64e-4 5.56e-4 5.29e-4 4.86e-4 4.21e-4 3.33e-4 2.14e-4 9.43e-5 2.35e-5 6.64e-7 PAN 7.17e-6 6.12e-5 6.00e-5 5.65e-5 5.08e-5 4.26e-5 3.22e-5 1.95e-5 7.90e-6 1.81e-6 4.80e-8 HCHOR-06 2.53e-4 2.76e-3 2.72e-3 2.59e-3 2.36e-3 2.03e-3 1.58e-3 9.85e-4 4.05e-4 9.08e-5 2.35e-6 HCHOM-06 6.12e-4 3.12e-3 3.08e-3 2.97e-3 2.77e-3 2.47e-3 2.02e-3 1.37e-3 6.41e-4 1.69e-4 5.00e-6 CCHO_R 2.53e-5 4.16e-4 4.06e-4 3.75e-4 3.27e-4 2.60e-4 1.81e-4 9.50e-5 2.99e-5 4.86e-6 8.30e-8 C2CHO 1.05e-4 1.40e-3 1.37e-3 1.28e-3 1.14e-3 9.29e-4 6.74e-4 3.80e-4 1.36e-4 2.62e-5 5.79e-7 ACET-06 3.85e-6 6.47e-5 6.28e-5 5.69e-5 4.78e-5 3.60e-5 2.32e-5 1.10e-5 3.05e-6 4.50e-7 7.35e-9 MEK-06 6.96e-5 9.66e-4 9.45e-4 8.80e-4 7.78e-4 6.33e-4 4.56e-4 2.54e-4 8.86e-5 1.66e-5 3.53e-7 COOH 7.11e-5 3.94e-4 3.89e-4 3.71e-4 3.42e-4 2.99e-4 2.40e-4 1.58e-4 7.21e-5 1.89e-5 5.51e-7 GLY-07R 9.60e-4 9.06e-3 9.00e-3 8.78e-3 8.44e-3 7.86e-3 6.97e-3 5.39e-3 3.29e-3 1.35e-3 1.31e-4 GLY-07M 4.40e-4 3.18e-3 3.14e-3 3.00e-3 2.78e-3 2.44e-3 1.98e-3 1.33e-3 6.41e-4 1.91e-4 8.80e-6 MGLY-06 1.02e-3 1.56e-2 1.56e-2 1.52e-2 1.47e-2 1.38e-2 1.24e-2 9.83e-3 6.27e-3 2.72e-3 2.87e-4 BACL-07 2.06e-3 2.67e-2 2.66e-2 2.61e-2 2.54e-2 2.40e-2 2.18e-2 1.75e-2 1.12e-2 4.81e-3 4.67e-4 BALD-06 1.32e-2 5.10e-2 5.05e-2 4.88e-2 4.61e-2 4.17e-2 3.52e-2 2.49e-2 1.26e-2 3.71e-3 1.17e-4 AFG1 6.82e-2 3.87e-1 3.83e-1 3.70e-1 3.50e-1 3.17e-1 2.69e-1 1.94e-1 1.04e-1 3.51e-2 1.99e-3 MACR-06 3.43e-5 1.97e-4 1.94e-4 1.86e-4 1.72e-4 1.51e-4 1.21e-4 7.98e-5 3.64e-5 9.42e-6 2.74e-7 MVK-06 1.32e-5 7.50e-5 7.40e-5 7.07e-5 6.54e-5 5.73e-5 4.60e-5 3.02e-5 1.37e-5 3.51e-6 1.01e-7 IC3ONO2 1.82e-5 2.35e-4 2.30e-4 2.15e-4 1.91e-4 1.57e-4 1.15e-4 6.57e-5 2.41e-5 4.80e-6 1.11e-7 [a] Photolysis rates for a chamber experiment with blacklight light source. The chamber photolysis rates are for the experiments carried out for this project. [b] See Carter (1994) for documentation of solar ac tinic fluxes used in the atmospheric reactivity calculations. [c] Calculated using absorption coefficients and cross sections given by Carter (2009)