SUMMARY OF REACTIVITY-RELATED CHAMBER PROJECTS AT UCR By William P. L. Carter CE-CERT, University of California, Riverside Overview Summary of recent and ongoing projects for UCR EPA chamber Results of tests of base mechanisms Preliminary results of coatings reactivity study Selected water-based solvent VOCs Selected petroleum distillates Future research directions for chamber W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

DIAGRAM OF UCR EPA CHAMBER W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

PHOTOGRAPHS OF CHAMBER AND LIGHTS Looking Towards Reactors (from light) Looking Towards Lights and Air Inlet Reflective walls and Ceiling Black Lights Arc Light Partially Filled Reactors Reflective walls Air Intake W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

SUMMARY OF CHAMBER PROJECTS TO DATE “Development of a Next-Generation Environmental Chamber Facility …” Funded by U.S. EPA Funded chamber construction and initial characterization Initial exploratory experiments: Low NOx experiments with selected VOCs Reactive organic gas (ROG) surrogate – NOx experiments at varying ROG and NOx levels Incremental reactivity of m-xylene and n-octane at varying ROG and NOx levels Status: complete. Report in preparation W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

SUMMARY OF CHAMBER PROJECTS TO DATE “Development and Evaluation of a Gas-Phase Atmospheric Reaction Mechanism for Low NOx Conditions” Funded by the California Air Resources Board Primary objective is to evaluate the SAPRC-99 mechanism using previous and new low NOx environmental chamber data A limited number of low NOx ROG surrogate runs carried out for this project Data from the CSIRO and TVA chambers also used in this evaluation Project completed. Reporte available at http://www.cert.ucr.edu/~carter/absts.htm#lnoxrpt W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

SUMMARY OF CHAMBER PROJECTS TO DATE (continued) “Experimental Evaluation of Observational Based Methods for Evaluating the Sensitivity of O3 to VOCs and NOx” Funded by U.S. EPA Objective is to provide data to evaluate OBMs using well-characterized chamber data ROG Surrogate – NOx experiments at varying ROG and NOx with measurements of key radical and “indicator” species Collaborated with Bill Brune of Penn State University to provide OH, HO2, and “OH reactivity” measurements using LIF Successfully completed 20 dual-chamber surrogate experiments with radical measurements; 40 separate ROG/NOx irradiations Report and journal articles in preparation W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

TESTS OF BASE MECHANISM Ambient ROG surrogate – NOx experiments 8-component ROG surrogate used to represent major classes of emitted VOCs (n-butane, n-octane, ethene, propene, trans-2-butene, toluene, m-xylene, formaldehyde) Test ability to predict O3 as function of ROG and NOx Establish model performance for “base case” used in incremental reactivity experiments and calculations Aromatic mechanism evaluation experiments Aromatics have significant impact on predicted ambient O3 but also have highly uncertain mechanisms Parameterized mechanisms adjusted to fit chamber data New aromatic – NOx and Aromatic – NOx + CO experiments provide new type of test for aromatics mechanism. W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

EFFECT OF CO ON AROMATIC - NOx RUNS E:\CHAMCALC\EPACHAM\REPFIT3.XLS W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

EFFECTS OF ADJUSTMENTS TO PARAMETERIZED TOLUENE MECHANISM H:\mech\saprc99\NewTol.xls W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

MATRIX OF ROG SURROGATE – NOx EXPERIMENTS IN UCR EPA CHAMBER MIR Reactivity Base Case MOIR / 2 Reactivity Base Case X:\epacham\surgnox.xls W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

LOW NOx SURROGATE EXPERIMENT (ROG SURROGATE = 300 PPBC, NOx = 2 PPB) E:\CHAMCALC\EPACHAM\REPFIT3.XLS W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

EXAMPLE DATA FROM AN OBM EXPERIMENT G:\TXT\epacham\obm\exdata.xls W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

EXPERIMENTAL AND CALCULATED O3 FOR CURRENT BASE CASE REACTIVITY EXPERIMENTS SAPRC-99 Model simulations of representative experiments MIR BASE CASE (NOx=30 ppb, ROG=0.5 ppmC) MOIR / 2 BASE CASE (NOx=25 ppb, ROG=1 ppmC) W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

DEPENDENCE OF SAPRC-99 UNDERPREDICTION BIAS ON RELATIVE ROG/NOx LEVELS G:\txt\arbpgm\lownox\present.xls “2004 eval” sheet, col AB W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

EFFECT OF PARAMETERS AND MECHANISM ON O3 PREDICTIONS FOR UCR EPA SURROGATE RUNS \\ozone\carter\epacham\SurgNox.xls (“Plots” sheet, column BF) ROG/NOx Ratio relative to ratio giving maximum O3 W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

Reactivity-Related Chamber Projects at UCR PRELIMINARY CONCLUSIONS FROM NEW BASE CASE REACTIVITY AND AROMATICS DATA SAPRC-99 mechanism predicts O3 reasonably well in low NOx and high ROG/NOx ambient simulation experiments SAPRC-99 consistently underpredicts O3 in low ROG/NOx ambient simulation experiments Problem even worse with CB4 Conditions where O3 is most sensitive to VOCs (MIR) Complicates use of MIR incremental reactivity experiments to assess mechanisms for added VOCs Results of new aromatic – NOx + CO experiments suggest problems with formulation of current aromatics mechanisms Aromatics mechanism formulation problems may be reason for O3 underprediction in low ROG/NOx ambient simulations W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

SUMMARY OF CHAMBER PROJECTS TO DATE (continued) “Evaluation of Atmospheric Impacts of Selected Coatings VOC Emissions” Funded by the California Air Resources Board Objective is to reduce uncertainties in O3 impact estimates of major types of coatings VOCs where reactivity data needed Environmental chamber incremental reactivity experiments were carried out for Texanol®, an important component in water-based coatings, and various types of petroleum distillates. Experiments carried out at two ROG and NOx conditions and evaluated using SAPRC-99 mechanism Most experiments completed, data now being analyzed W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

SUMMARY OF CHAMBER PROJECTS TO DATE (continued) “Environmental Chamber Studies of VOC Species in Architectural Coatings And Mobile Source Emissions” Funded by the South Coast Air Quality Management District Primarily supplements CARB architectural coatings reactivity project to allow for additional work: PM measurements during reactivity experiments Incremental reactivity experiments with ethylene and propylene glycols, benzyl alcohol, and butyl carbitol Limited experiments to investigate interactions between glycols and aerosols for availability assessment Experiments near completion and being analyzed W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

MEASUREMENT OR CALCULATION OF OZONE REACTIVITIES OF VOCs Ozone reactivities of VOCs cal be calculated using computer airshed models, given: Models for airshed conditions Chemical mechanism for VOC’s Atmospheric Reactions BUT mechanisms have uncertainties. reactivity calculations can be no more reliable than the chemical mechanism used. Reactivities can also be measured in chamber experiments, but the results are not the same as reactivity in the atmosphere. Impractical to duplicate all relevant conditions Chamber experiments have wall effects, static conditions, higher levels of test VOCs, etc. Therefore, the purpose of chamber experiments is to test the ability of the mechanisms to predict reactivity in models W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

VOCs IDENTIFIED IN 1998 CALIFORNIA SURVEY OF WATER-BASED ARCHITERCURAL COATINGS Compound Mass % Structures “Texanol®” Isobutyrate esters of 2,2,4-Trimethylpentyl-1,3-diol 28% (1) (2) Propylene Glycol Ethylene Glycol 16% Various Petroleum Distillates (Main constituents of solvent-based coatings) 5% C8+ Alkanes and Aromatics “Butyl Carbitol”: 2-(2-Butoxyethoxy)-Ethanol 4% See g:\txt\arbpgm\coatings\texanol.xls and G:\txt\arbpgm\coatings\rctruns.xls for structures. W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

SAPRC-99 MECHANISM GENERATION SYSTEM Used to derive SAPRC-99 mechanisms for alkanes, glycols, esters, etc. Automated mechanism generation procedure Estimation methods used to derive unknown rate constants and ratios Measured rate constants and branching ratios used where known. “Lumping Rules” use to derive condensed mechanism for model W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

REACTIVITY DATA FOR TEXANOL® G:\txt\epacham\RctTalk.xls “TEXANOL” sheet W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

REACTIVITY DATA FOR BUTYL CARBITOL G:\txt\epacham\RctTalk.xls “DGBE” sheet W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

COMPARISON OF CHAMBER AND AMBIENT REACTIVITY CALCULATION FOR TEXANOL® Two curves almost on top of each other G:\txt\meetings\rrwg\rrwg1104.xls “Added Texanol” sheet W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

REACTIVITY DATA FOR ETHYLENE AND PROPYLENE GLYCOLS G:\txt\epacham\RctTalk.xls “Glycols” sheet W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

OH RADICAL RATE CONSTANTS DERIVED FROM CHAMBER DATA Compound kOH (cm3 molec-1 s-1) Texanol 1 1.29 x 10-11 Texanol 2 1.62 x 10-11 Butyl Carbitol 4.29 x 10-11 G:\txt\arbpgm\coatings\kOH.xls W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

Reactivity-Related Chamber Projects at UCR GLYCOL DECAY RATES IN REACTIVITY RUNS: COMPARISON WITH LITERATURE K(OH) VALUE G:\TXT\EPACHAM\SCAQMD\GlyKoh.xls “PR-GLYCL” sheet. Scale=135% W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

Reactivity-Related Chamber Projects at UCR GLYCOL DECAY RATES IN REACTIVITY RUNS: COMPARISON WITH LITERATURE K(OH) VALUE G:\TXT\EPACHAM\SCAQMD\GlyKoh.xls “PR-GLYCL” sheet. Scale=135% W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

PRELIMINARY CONCLUSIONS FROM WATER-BASED COATINGS SOLVENT EXPERIMENTS The new data for Texanol® and butyl carbitol tend to support the estimates of the SAPRC‑99 mechanism generation system Very good predictions of OH rate constants “Acceptable” fits to chamber data without adjustments The SAPRC-99 mechanism may somewhat underestimate O3 impacts of ethylene and propylene glycols Need to improve the model simulation of the base case experiment to improve the utility of the MIR incremental reactivity experiments for mechanism evaluation W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

REPRESENTATIVE PETROLEUM DISTILLATES CHOSEN FOR REACTIVITY EXPERIMENTS Designation Carbon Range Aromatic Content MIR (gm/gm) Comment ASTM Type 3C1 Mostly 11 - 0.87 Mostly branched alkanes ASTM Type1C 9-12 0.98 VMP Naphtha 8-9 0.2% 1.4 Lower Molecular weight mixture ASTM Type 1B 6% 1.3 ASTM Type 1A 19% 2.1 Aromatic 100 Mostly 9 100% 7.5 Detailed analysis provided G:\txt\arbpgm\coatings\mscmps.xls W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

CHEMICAL TYPE DISTRIBUTIONS FOR PETROLEUM DISTILLATES STUDIED ASTM Type 3C1 ASTM Type 1C VMP Naphtha ASTM Type 1B ASTM Type 1A Aromatic 100 G:\txt\epacham\RctTalk.xls “MS Pie Plots” sheet 3C1, 1A Corrected 10/28/04 W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

REACTIVITY DATA FOR PETROLEUM DISTILLATES G:\txt\epacham\RctTalk.xls “MS Runs” sheet W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

REACTIVITY DATA FOR PETROLEUM DISTILLATES G:\txt\epacham\RctTalk.xls “MS Runs” sheet W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

Reactivity-Related Chamber Projects at UCR COMPARISON OF CHAMBER AND AMBIENT REACTIVITY CALCULATION FOR ASTM TYPE 1A G:\txt\meetings\rrwg\rrwg1104.xls “Added ASTM1C” sheet. Size=110% W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

PRELIMINARY ASSESSMENT OF MODEL PERFORMANCE FOR PETROLEUM DISTILLATES Designation Major Components Model Performance for O3 ASTM Type 3C1 C11 Branched Alkanes Model underestimates O3 impact ASTM Type1C C9-C12 Alkanes Not inconsistent with data VMP Naphtha C8-C9 Alkanes ASTM Type 1B C9-C12 Alkanes with ~6% Aromatics ASTM Type 1A C9-C12 Alkanes with ~20% Aromatics May underpredict O3 inhibition at low NOx Aromatic 100 Methyl ethyl and trimethyl Benzenes Underpredicts O3 inhibition at low NOx W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

SUMMARY OF CHAMBER PROJECTS TO DATE (continued) “Updated Chemical Mechanisms for Airshed Model Applications” Funded by the California Air Resources Board Major effort is updating and improving the SAPRC mechanism: Updating to be consistent with current literature Improving performance for aromatics and low ROG/NOx Developing condensed version for models to replace CB4 Includes limited funding to support mechanism update effort (primarily for aromatics) (~10 runs) Project is now underway W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

SUMMARY OF CHAMBER PROJECTS TO DATE (continued) “Utilization of a Next Generation Environmental Chamber Facility ...” Funded by the U.S. EPA Primary objective is to support research utilizing chamber for O3 and secondary PM mechanism evaluations Experiments to be conducted include: Studies of temperature and humidity effects on O3 and SOA PM and SOA formation characterization experiments Study effects of variable ROG and NOx on and SOA Funding only recently made available. W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

SUMMARY OF CHAMBER PROJECTS TO DATE (continued) PM Characterization and Secondary PM Formation Assessment Studies Carried out in collaboration with Dr. David Cocker of CE-CERT Funded in part by the SCAQMD and EPA projects and in part by other CE-CERT programs Experiments include PM characterization and background experiments, and experiments for comparison with data from other chambers Studies of SOA formation from aromatics and the ROG surrogate mixture under various conditions Work is underway. Some manuscripts submitted for publication W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR

FUTURE RESEARCH DIRECTIONS FOR UCR EPA CHAMBER Continue O3 reactivity and mechanism evaluation experiments for VOCs of interest Utilize the capabilities of chamber for well-characterized SOA studies needed for SOA model development and evaluation Investigate temperature and humidity effects on O3 and SOA Obtain instrumentation needed for NO3, N2O5, HOx, and other trace species to improve capabilities and utility of this facility Serve as a resource for collaborative studies where environmental chamber measurements under highly controlled and characterized conditions would be useful Serve as test bed for instrumentation for ambient monitoring W. P. L. Carter 9/17/2018 Reactivity-Related Chamber Projects at UCR