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Larry Tavlarides & Meera Sidheswaren, Syracuse University and Phil Hopke & Xi Chen, Clarkson University. Fate Formation And Transport Of Indoor PM EPA04 T2.2. Task 2.2 Introduction.
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Larry Tavlarides & Meera Sidheswaren, Syracuse University and Phil Hopke & Xi Chen, Clarkson University Fate Formation And Transport Of Indoor PMEPA04 T2.2
Task 2.2 Introduction • Epidemiological studies link “reactive” fine particles to human health hazards including mortality (Pope and Dockery, 1996; USEP, 1997), especially those generated indoors (Long et al., 2001) • Important to know chemistry of particle formation, the nature of VSVOC’s formed, and the fate of VSVOC’s due to interactions with room surfaces and secondary organic aerosols (SOA’s) • Terpene and terpene-alcohol ozone reaction systems will be studied as these compounds exist in room fresheners, perfumes and laundry softeners.
Formation of SOA Initial Models
Formation of SOA More Complete Models – Odum et al., ES&T 1997; Liang et al ES&T 1997
Objectives: Task 2.2.4 Ozone Reactions of Linalool and Adsorption of VOC and SVOC By-Products on Surfaces and SOA • Understand the kinetic mechanism which describes the gas phase reaction of linalool with ozone. These studies will be performed in the 150 ft3 stainless steel chamber. • Determine the adsorption and desorption behavior of VSVOCs on building surfaces. These studies will also be performed in the same chamber with all walls exchanged with building materials. • Characterize the growth of SOAs due to the adsorption of VSVOCs and develop size distribution and growth dynamic models.
Reaction Pathway Study Branch 1 Branch 2
Mass Spectra of Some Products 2-Ethenyl-5-methyl-5-hydroxytetrahydrofuran 2-(3-H)-Furanone-5-ethenyldihydro-5-methyl- 2-Furancarboxylicacidtetraydro-1-methyl-5-oxo 2-Hydoxy2,3-dimethylsuccinic acid
Particle Phase Analysis Similar to the analysis by Leungsakul et al., 2005
Particle Size Distribution Linalool Concentration: ~100 ppb; Ozone Concentration: ~100 ppb Time of Sampling : Continuous. Time Scale: Reading 1: 15mins Reading 19: 285mins
Yield Model Linalool Concentration: 500ppb, Ozone Concentration: 500ppb, Humidity: 25% (T. Hoffmann, J. Odum, et al., 1997)
T2.2.4: Results • The 150 ft3 chamber has been built, commissioned and is fully functional. Diffusion cell for continuous linalool injection is being fabricated. • Gas and particle phase analyses using GC-MS technique have been developed. • Initial qualitative analyses of products for preliminary estimation of the reaction pathway has been completed in the 100 L chamber. • Two major products of linalool ozone reaction have been synthesized
T2.2.4: Future Work • Quantification of significant linalool ozone products • Proposed experiments for the particle size distribution and yield of SOA’s in the 150 ft3 chamber will be executed. • Obtain sorption data for suggested building materials to quantify particle adsorption on surfaces. • Obtain parameters for secondary organic aerosol growth models and describe the dynamics of aerosol formation.
Formation of Indoor Particles a-Pinene and Ozone • There have been many studies of the a-Pinene and Ozone system. • However, many of these studies have been performed to provide critical reaction rate constants for chemical transport models. • Thus, the reactions with ozone need to be separated from the reactions with hydroxyl radical. • For example, Presto and Donahue (ES&T 2006) summarize much of the prior data along with their chamber results where a hydroxyl radical scavenger like butanol has been added to the chamber
Formation of SOA a-Pinene and Ozone
Formation of Indoor Particles Current Progress • Much of this year has been used to develop and test the experimental systems: • Chamber • Ozone Generation • Reactive VOC Generator • Particle Measurement System • Particle Composition Measurements
Formation of SOA a-Pinene and Ozone
Formation of SOA a-Pinene and Ozone – Experiment 1
Formation of SOA a-Pinene and Ozone - Experiment 2
Formation of SOA a-Pinene and Ozone
Formation of SOA a-Pinene and Ozone Figure from Fan et al., ES&T 2003.
Formation of Indoor Particles Current Progress • Thus, initial results appear comparable with prior flow through chamber results. • We need to extend the time to longer periods to examine steady-state behavior. • We need to measure ROS concentrations resulting from the new particle formation. • In other studies, we have been examining the nature of the reaction products for a-pinene and ozone.
Formation of Indoor Particles Future Work • We will continue the work with a-pinene and ozone to obtain the D(Particle Formation) v D(Hydrocarbon Reacted) to provide results without the OH scavenger to provide curves relevant to indoor air modeling. • To explore other possible reactive VOCs, we have started to explore the presence of compounds in a series of commercial air fresheners • Analysis of a number of commercial air freshener products by GC/MS.
Possible SOA Precursors Found Limonene Terpineol Methyl-cinnamaldehyde Eugenol Rose Oxide Linalyl butyrate Beta-Ionone Linalyl anthranilate a-bergamotene a-Isomethylionone Hexenylsalicylate Muurolene Cis-verbenol
Results • Many of these compounds have more than one double bond. • These compounds behave differently from the single double bond compounds. • As an example, some chamber studies have been made on terpineol
Formation of SOA Terpinolene and Ozone Time-dependent growth curves and final growth curve do not overlap; time-dependent growth curves show the contribution of the secondary reactions
Results • These time-dependent growth curves for terpinolene ozonolysis cannot be fit with Odum equation, confirming that this model is only valid when the data represent final SOA growth. • We will need to consider further how best to model the multiple stage reaction systems that the multiply double bonded compounds represent. • We need to decide what species to pursue following the completion of the a-pinene-ozone work • Terpineol • Others?
Discussion and Questions • Questions? • Suggestions?
Formation of SOA a-Pinene and Ozone
Formation of SOA a-Pinene and Ozone Time series of ozone concentration in the chamber
Formation of SOA a-Pinene and Ozone Time series of a-pinene concentrations from the diffusion cell for three different diffusion lengths
Characterization of ROS Species (Contd.) a-Isomethylionone Hexenylsalicylate Muurolene Cis-verbenol a-bergamotene Linalyl butyrate
Experimental Set-up • Experimental Apparatus • 100L / 4274.5L stainless steel chamber • Injection ports to inject linalool • API 400 Ozone generator • Dynacalibrator/Diffusion cell for Linalool generation • Analysis Techniques • API 440 Ozone Analyzer • ppB RAE for VOC monitoring • Tenax sorbents • Samples pulled out through an ozone trap using handheld socket pump (ozone trap made of potassium iodide) • PFPH coated Tanex for estimation of lower aldehydes (S.A. Hang Ho, J. Z. Hu, 2004)
Experimental Set-up (Contd.) • Analysis Techniques • ATD-GC/MS • ATD: Perkin Elmer Turbomatrix 300 (Sorption Temperature @ 210 oC) • GC-MS: Thermoelectron (Trace GC Ultra/DSQ) • GC Column: Restek 5MS • Temperature of Operation: Ramp to 200 C(@ 25oC/min) and holdup for 10 mins • Particle Collection • TSI 3086 Nano-Aerosol Sampler (Sampling size range: 2nm-100nm) • Teflon Filter/Membrane Filter:>200nm • Analysis using GC/MS after extracting particles with methanol using overnight Soxhlet Extraction