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Ph.D. Dissertation Defense final version
- 1. Water-soluble organic gases in residential indoor air, and the potential for aqueous chemistry indoors to alter exposures Sara Duncan February 23, 2018 Dissertation Defense
- 2. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Motivation: time spent indoors 2 Klepeis et al., JEAEE 2001
- 3. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions 3 Paciência et al. JTEH 2016 I/O: 150- 10- 1- 0.5- VOCs (n=38) Motivation: enhanced exposure to (nonpolar) VOCs
- 4. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Motivation: dampness in homes • 18 - 50% of homes are damp • Associated with adverse health outcomes • Unsure of causal agents • Microbial exposures – most commonly explained culprit, but may not be the whole picture • What else is occurring? Mendell et al., EHP 2011 4
- 5. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions 5 Presence and characteristics of liquid water Composition and concentrations of oxidized VOCs aka. water-soluble organic gases Critical knowledge gaps in indoor air chemistry
- 6. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Hypothesis I hypothesize that water-soluble organic gases (WSOG) are ubiquitous and abundant in homes, and their subsequent aqueous uptake and processing alters the chemical composition of indoor air. 6
- 7. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Objectives • Synthesize literature: determine previously measured WSOG and hypothesize additional WSOG • Collect WSOG in homes: characterize integrated composition of WSOG • Characterize sampling method • Characterize WSOG in real-time in one home • Postulate the presence of liquid water indoors and subsequent occurrence of aqueous chemistry 7
- 8. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions What do we already know about WSOG in homes? Which ones have been measured? What else do we expect to be there? Conduct literature search: determine WSOG previously measured and hypothesize others expected to be present 8
- 9. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions 9 Compound Structure Henry's law constant (M/ atm) Mean (and range) Gas phase concentrations (ppb) Glyoxal 4,000,000 1 (0.5 – 1.8) Methylglyoxal 32,000 0.9 (0.4 – 1.6) Formaldehyde 3,000 22 (4 – 100) Acetone 31 16 (0.4 – 280) 2-Butanone 18 2 (BDL* – 8.4) Acetaldehyde 15 7.4 (0.7 – 23) Propionaldehyde 13 1 (BDL – 7.3) 2-Hexanone 11 0.13 (NA* – 0.8) Tetrahydrofuran 10 0.44 (NA – 83) Acrolein 10 0.25 (BDL – 2.4) Examples of WSOG previously measured *BDL = below detection limit *NA = not available Duncan et al., IA 2017 & refs therein
- 10. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Examples of WSOG likely to be emitted 10 Emission source WSOG emitted Building occupants Acids Ketones AlcoholsCooking Fireplace Oxidized aromatics Aldehydes Ketones Dicarbonyls Microbial VOCs Aldehydes Acids Ethers Esters Ketones Duncan et al., IA 2017 & refs therein
- 11. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions 11 Low solubility precursor Oxidant Soluble product C5-C8 n-alkanes (attached garages) OH· Hydroxycarbonyls Monoterpenes (cleaning products, wood floors, e.g. α-pinene, β-pinene, limonene) O3 Aldehydes Acids OH· Aldehydes Ketones Alkylbenzenes (building materials, furniture, attached garages) OH· Oxidized aromatics Hydroxyl dicarbonyls Squalene (human skin lipid) O3 Ketones Acids Alcohols Isoprene (indoor plants, people) OH· Carbonyls Hydroperoxides Epoxides NO3· Organic nitrates Hydroxycarbonyls Examples of WSOG likely to form through gas phase chemistry Duncan et al., IA 2017 & refs therein
- 12. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions WSOG in literature: summary 12 • Some WSOG have been measured indoors • These compounds have well developed analytical methods • Many more WSOG are emitted from common indoor sources • Many more WSOG are likely to be formed indoors
- 13. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Are WSOG also elevated indoors? What are their characteristics? Conduct integrated measurements of WSOG in real homes and perform subsequent chemical analysis 13
- 14. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Collect WSOGs 14 Mist chambers (MCs) collect water-soluble organic gases Mist 25 L/min 25 mL Scrubbed air (to pump) Sampled air (particle filtered) Refluxing liquid Cofer et al., ES&T 1985
- 15. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Sampling parameters 15 •Sampled 13 real homes (1x each) •June – October 2015 •Sampling time: ~ 10:00AM – 2:00PM Sample for 2 hours x 2 Inside homes Outsidehomes
- 16. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Characterize homes 16 Parameter Average (range) Measured in home Temperature (˚C) 23 (20-26) Relative Humidity (%) 60 (53-67) Carbon dioxide (ppm) 930 (620-1390) Reported from nearby outdoor monitoring site Ozone (ppb) 40 (8-60) Temperature (˚C) 25 (15-33) Calculated Floor area (m2 ) 140 (40-230) Air exchange rate (h-1 ) 0.5 (0.3-0.8)
- 17. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Compare indoor and outdoor WSOG concentrations 17 Total organic carbon analyzer Conduct carbon analysis
- 18. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Water-soluble organic gas concentrations are significantly higher indoors than outdoors 18 Paired t-test, α=0.05, p < 0.001 Indoor gas-phase concentration – mean (range): 145 µg-C/m3 (84-215) Outdoor gas-phase concentration – mean (range): 11 µg-C/m3 (4-16) Estimate of WSOG of indoor origin: 86%
- 19. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Predictors of WSOG indoors 19 Step-wise multiple linear regression p-value of <0.05 Indoor WSOG Outdoor WSOG Indoor T Outdoor T ∆ T Indoor RH Outdoor O3 Indoor CO2 Occupants Year built Home area p=0.008 R2 = 0.61
- 20. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Total WSOG decreases with air exchange rate 20 Equation 11, Chan et al., AE 2005: H = building height (m) NL = normalized leakage (function of year built and floor area) F = scaling factor = 16 𝐴𝐸𝑅 (ℎ−1 ) = 48 2.5 𝑚 𝐻 0.3 𝑁𝐿 𝐻 × 𝐹
- 21. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Quantify organic acid portion of WSOG 21 Ion chromatography Detect anions
- 22. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Organic acids constitute a significant portion of WSOG 22 Acetic + lactic acids (quantified as acetic): 18 to 53% of total WSOG - carbon Formic acid: 3 to 12% of total WSOG - carbon What can ESI-MS tell us about the remainder?
- 23. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Identify molecular formulas for the remainder of WSOG 23 Electrospray ionization mass spectrometry (positive mode) Obtain precise molecular weights of compounds
- 24. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Most compounds contain oxygen, many contain nitrogen 24 Compound type Average (%) CHO 67 CHON 11 CHN 11 Other 11 98 total molecular formulas
- 25. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions 1 2 3 4 5 6 7 8 9 10 11 12 13 WSOG in homes varies greatly and is quite complex245m/z+59Home #: 25 Diethylene glycol Diethylene glycol butyl ether 157.0835 – C4H10O3 163.1328 – C8H18O3 Not detected in sample Detected in sample
- 26. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Formula Possible compound Source Functional groups C3H6O Acetone solvent, plants ketone C4H10O3 Diethylene glycol solvent ether, alcohol C5H8O2 Methyl methacrylate plasticizer ester C6H12O Hexanone solvent ketone C6H14O3 Dipropylene glycol plasticizer ether, alcohol C8H18O3 Diethylene glycol butyl ether pesticides, solvent alcohol, ethers C12H17NO DEET insect repellent ketone, amine Preliminary compound identification 26
- 27. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Formula Possible compound Source Functional groups C3H6O Acetone solvent, plants ketone C4H10O3 Diethylene glycol solvent ether, alcohol C5H8O2 Methyl methacrylate plasticizer ester C6H12O Hexanone solvent ketone C6H14O3 Dipropylene glycol plasticizer ether, alcohol C8H18O3 Diethylene glycol butyl ether pesticides, solvent alcohol, ethers C12H17NO DEET insect repellent ketone, amine Preliminary compound identification 27
- 28. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Formula Possible compound Source Functional groups C3H6O Acetone solvent, plants ketone C4H10O3 Diethylene glycol solvent ether, alcohol C5H8O2 Methyl methacrylate plasticizer ester C6H12O Hexanone solvent ketone C6H14O3 Dipropylene glycol plasticizer ether, alcohol C8H18O3 Diethylene glycol butyl ether pesticides, solvent alcohol, ethers C12H17NO DEET insect repellent ketone, amine Preliminary compound identification 28
- 29. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Integrated measurements: summary 29 • WSOGs are elevated indoors (15 x higher in sampled homes) • Organic acids account for approximately 50% of collected WSOG • 98 distinct molecular formulas were identified in homes • Inter-home variability is high
- 30. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions What are the chemical dynamics of WSOG indoors? Conduct real-time, high resolution molecular identification of residential WSOG 30
- 31. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions 31 Iodide chemical ion mass spectrometry (I-CIMS) High resolution m/z- → elemental composition In real time → 2 second intervals Detects: organic acids, alcohols, ketones, organic peroxides, amines, and organic nitrates Conduct real-time measurements in one home under various conditions
- 32. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Sampling schedule 32 Date Perturbation 7/18/17 Background 7/19/17 No occupancy 7/20/17 High occupancy 7/21/17 Windows open/ AC off 7/22/17 Cleaning 7/23/17 Cooking 7/19, 8-hour max outdoor O3 = 51 ppb Supporting measurements
- 33. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Schematic of air sampled by CIMS instrument 33 Inside home Inside homeInside home Instrument Instrument Instrument Instrument inlet Sampling line (1 meter) Sampling inside air Sampling outside air Sampling inside air 20 min at ~ 8 AM and 2 PM 20 min, after outdoor air samplingNormal sampling
- 34. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions 34 Organic acids cycle approximately hourly Acetic acid ↓: 31-38% Formic acid ↓: 47-53%
- 35. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions 35 Cycling on of central air conditioning unit leads to scrubbing of organic acids from air
- 36. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Other compounds cycle with the air conditioning system as well 36 ↑ O:C suggests ↑ uptake into AC system
- 37. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions A look at forced air conditioning systems in homes 37 Acetic + lactic acid = ~ 1000 μM Formic acid = ~ 350 μM
- 38. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions 38 Elevated concentrations indoors = indoor sources dominate Elevated concentrations outdoors = outdoor sources dominate
- 39. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions 39 Lactic acid concentrations increase from increased occupancy and cooking events
- 40. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Other compounds also spike with cooking events 40
- 41. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Real-time measurements: summary 41 • Central air conditioning systems take up WSOGs • Likely due to condensation in the condensate tray and/ or duct work • Some compounds are dominated by indoor sources, some outdoor sources • Cooking events are a substantial source of WSOG indoors
- 42. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions WSOG are elevated indoors; what happens to them if liquid water is present? Making the case for aqueous chemistry in homes 42
- 43. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Cloud evaporation SOA ·OH ·OH ·OH NOx ·OH ·OH ·OH NOx NOx, alkenes, aromatics O O O O ·OH O3 ·OH Isoprene Utilize insights from outdoor aqueous chemistry 43 • Atmospheric water is found in clouds, fogs, wet aerosol • Changes composition of gases, particles, and oxidants • Faster and different products
- 44. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Provide evidence for liquid water in homes 44 Surface-to-volume ratios: ~ 3 m2/m3 indoors vs. < 0.01 m2/m3 outdoors Liquid water condensed in AC = 2.2 ± 0.2 L RH = 80%RH = 70% (↓ 10%) Water uptake = 3 mL/m2 Künzel et al., ASHRAE 2004
- 45. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Postulate on subsequent aqueous chemistry 45 • Radical reactions, acid-base, nucleophilic and hydrolysis reactions • Surface films – similar chemistry to that of wet particles • Bulk water – similar chemistry to that of clouds and fogs • Some products will remain in the condensed phase, while others volatilize back into the gas phase • Magnitude of reactions will likely act as significant source and compete against air exchange
- 46. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Identify the critical unknowns 46 •Contributions by compound class and molecular structure to WSOG •Hygroscopicity of indoor surfaces •Characteristics of liquid water on indoor surfaces •Dominant chemistry in indoor liquid water
- 47. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Aqueous chemistry: summary 47 • Liquid water is present in homes, especially damp homes • There are many WSOG indoors that can partition into liquid water if present • Aqueous chemistry substantially alters outdoor air composition • Aqueous chemistry is also likely to alter indoor air composition
- 48. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Overall conclusions 48 1. Some WSOG have been identified previously indoors, more are likely present 2. Much more WSOG indoors than outdoors (mean = 15x) 3. WSOG chemical makeup is quite complex and varied between homes (98 molecular formulas identified in integrated samples) 4. Air conditioning systems are a large sink for WSOG (30-50% for acetic and formic acids) 5. Most WSOG originate indoors, some outdoors 6. With the ubiquitous presence WSOG indoors and evidence for liquid water, aqueous chemistry is likely to occur
- 49. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Hypothesis 49 I hypothesize that water-soluble organic gases (WSOG) are ubiquitous and abundant in homes, and their subsequent aqueous uptake and processing alters the chemical composition of indoor air.
- 50. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Final thoughts 50 •First broad look at WSOG in homes •WSOG merit further identification and quantification •Evidence that liquid water is indoors •Aqueous chemistry is likely to happen •Occupants will be exposed to WSOGs and products of aqueous chemistry. What are the health implications?
- 51. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Future work 51 • Further identify and quantify WSOG indoors • Explore WSOG uptake and subsequent chemistry in liquid water indoors • Conduct exposure studies to determine health effects
- 52. Thank you and acknowledgements! 52 Sara Duncan, email: saraduncan31@gmail.com Adviser: Dr. Barbara Turpin Committee: Dr. Clifford Weisel, Dr. Gediminas Mainelis, Dr. Charles Weschler Lab group: Dr. Neha Sareen, Dr. Jeff Kirkland, Dr. Natasha Hodas, Ronald Lauck, Dr. Kenneth Sexton, Dr. Sophie Tomaz, Marc Webb Other scientists: Dr. Jason Surratt, Dr. Glenn Morrison, Leonard Collins, Yuzhi Chen, Rutgers exposure science group Support staff at both Rutgers and UNC Research volunteers in New Jersey and North Carolina My family (especially my parents) Many friends (especially those that I’ve met during my time at Rutgers and UNC) Funding: National Institute of Environmental Health Sciences and Sloan Foundation
- 53. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Mist chamber characterization - collection time 53 1hr 8hr MC: 1 2 3 4 7.5 min 15 min 30 min 1 hr 7.5 min 7.5 min 15 min 7.5 min 7.5 min 15 min 30 min 7.5 min 7.5 min 15 min 7.5 min 1 hr 2 hr 4 hr 8 hr 1 hr 1 hr 2 hr 1 hr 1 hr 2 hr 4 hr 1 hr 1 hr 2 hr 1 hr MC: 1 2 3 4
- 54. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions 54 10 min: KH>103 M/atm η = 80-100% 1 (glyoxal, hydroxyacetone, formaldehyde) Spaulding et al., ES&T 2002 H-law equilibrium at t=? Increasing sample time allows for collection of a larger range of water-soluble compounds Further collection of less soluble compounds, 1<KH<103 M/atm
- 55. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Mist chamber characterization - collection efficiency 55 1stinseries 2ndinseries 1stinseries 2ndinseries MC: 1 2 3 4 𝐶𝐸 ≈ 1 − 𝐶2 𝐶1 = 43% 1 Spaulding et al., ES&T 2002, SI
- 56. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions Cleaning produces many chlorinated compounds 56
- 57. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions 57 2NO2 + H2O → HONO + HNO3 early study of 10 homes by Spengler and Brauer, who found HONO concentrations ranging from 2 to 8 ppb (Spengler et al., 1993). Recently, measured indoor OH radical concentrations of 1.8 x 106 molecules/m3 were linked to HONO photolysis on windows (Gómez Alvarez et al., 2013).
- 58. Introduction WSOG in literature Integrated measurements Real-time measurements Aqueous chemistry Conclusions 58 Compound Structures Henry's law constant (M/ atm) Mean (and range) gas phase concentrations (ppb) Mean (and range) potential aqueous concentration (µM) Glyoxal 4,000,000 1 (0.5 – 1.8) 4,300 (1,900 – 7,500) Formaldehyde 3,000 22 (4 – 100) 66 (10 – 300) Methylglyoxal 32,000 0.9 (0.4 – 1.6) 30 (10 – 50) Acetone 31 16 (0.4 – 280) 0.5 (0.01 – 9) Acetaldehyde 15 7.4 (0.7 – 23) 0.11 (0.01 – 0.3) 2-Butanone 18 2 (BDL – 8.4) 0.035 (≤ 0.15) Propionaldehyde 13 1 (BDL – 7.3) 0.012 (≤ 0.1) Tetrahydrofuran 10 0.44 (NA – 83) 0.0044 (≤ 0.84) Acrolein 10 0.25 (BDL – 2.4) 0.0026 (≤ 0.024) 2-Hexanone 11 0.13 (NA – 0.8) 0.0014 (≤ 0.009) WSOGs will partition into liquid water
Editor's Notes
- The National Human Activity Pattern Survey
- VOC examples – alpha pinene and ethyl acetate
- high relative humidity (RH), presence of mold, presence of standing water, and damp building materials
- 2-butanone, lactic acid, acrolein, Overall presence of water on indoor surfaces Hydrolysis, acid-base, and oxidation-reduction reactions may occur https://www.angieslist.com/articles/how-fix-condensation-windows.htm http://www.owasa.org/What-Is-A-P-Trap
- 1. Conduct literature search for WSOG previously measured - Example search terms: “volatile,” “organic compounds,” “indoors,” “air,” “concentration,” “measured” - Identify compounds with Henry’s law constants > 1 M/atm
- Henry’s law = concentration in gas phase over concentration in aqueous phase at equilibrium Some WSOG have been measured: HPLC, GC-MS
- Acids e.g.: oxopentanoic acid, lactic acid, pyruvic acid Ketones e.g.: acetone Alcohols e.g.: ethanol, propanol, phenol Other e.g.: 4-oxopentanal Aldehydes e.g.: acetaldehyde, propanal, acrolein Ketones e.g.: 2-hexanone, 2-heptanone Alcohols e.g.: pentanol, hexanol, 1-octen-3-ol Phenols and substituted phenols e.g.: phenol, o-benzenediol, m- and p-cresol Guaiacol and substituted guaiacols e.g.: guaiacol, vanillin, eugenol Syringols and substituted syringols, e.g.: syringol, 4-methylsyringol Aliphatic aldehydes e.g.: formaldehyde, acetaldehyde, hexanal Aliphatic ketones e.g.: acetone, butanone Olefinic aldehdyes e.g.: acrolein , crotonaldehyde Aromatic carbonyls e.g.: benzaldehyde, m- and p-toluadehyde Dicarbonyls e.g.: glyoxal, methylglyoxal, biacetyl Volatile trihalomethanes e.g.: chloroform, bromodichloromethane, chrolodibromomethane, bromoform Volatile disinfection byproducts e.g.: 1,1,1,2-tetrabromo-2-chloroethane, 1,1,2,2-tetrabromo-2-chloroethane benzyl chloride Aldehydes e.g.: formaldehyde, propanol, benzaldehyde Acids e.g.: acetic acid, octanoic acid Ethers e.g.: anisole Esters e.g.: methyl acetate, ethyl acetate Ketones e.g.: cyclopentanone, 3-hydroxy-2-butanone, acetone
- Insights from atm chem and smog chamber work
- With help of Dr. Ken Sexton Red arrow flying in to mix Sampling device: Cofer Scrubber or Mist Chamber MCs filter out particles. Pressure drop pulls water up capillary tube and sprays into mist. Increases surface area between water and air. Water-soluble organic gases partition into water Advantage: MCs collect all WSOG. Collected into media that can be used for further analysis/ experimentation Mist chamber sampling inlets: 2 sampling in parallel indoors 2 sampling in parallel outdoors
- Conducted technician and participant survey to characterize homes 3 in NJ, 10 in NC during more or less summertime. No notable difference between the two. Lower ozone concentrations on rainy/ cloudy days. Summer time ozone can make WSOG
- Conducted technician and participant survey to characterize homes 3 in NJ, 10 in NC during more or less summertime. No notable difference between the two. Lower ozone concentrations on rainy/ cloudy days. Summer time ozone can make WSOG
- Accurate-Mass Quadrupole Time-of-Flight Liquid Chromotography/Mass Spectrometry with an Electrospray Ion Source (ESI Q-TOF LC/MS) Positive mode, soft ionization (fragmentor voltage = 40V)
- step-wise multiple linear regression
- Accurate-Mass Quadrupole Time-of-Flight Liquid Chromotography/Mass Spectrometry with an Electrospray Ion Source (ESI Q-TOF LC/MS) Positive mode, soft ionization (fragmentor voltage = 40V)
- Accurate-Mass Quadrupole Time-of-Flight Liquid Chromotography/Mass Spectrometry with an Electrospray Ion Source (ESI Q-TOF LC/MS) Positive mode, soft ionization (fragmentor voltage = 40V)
- Why higher N indoors?
- Iodide CIMS, negative mode Calibrated for formic, acetic, lactic acids, imidazole What does it measure?
- AA and FA also elevated indoors
- AA and FA also elevated indoors
- C2H4O3 – O:C=1.5 Glycolic acid C5H8O3 - O:C=0.6 Levulinic acid C4H8O2 - O:C=0.5 Ethyl acetate C5H10O2 - O:C=0.4 Ethyl propionate C7H14O2 - O:C=0.3 Amyl acetate C8H8O3 - O:C=0.4 Vanillin
- Add inlet sampling
- Hydroperoxyl Examples: sink: SO2, HO2·, glyoxal source: sulfuric acid, oxalate, oligomers, PM
- Aluminum walls vs gypsum wallboard
- WSOGs with high Henry’s Law Constant likely to partition into liquid water Water films likely to be highly concentrated with salts and organics Although many will be slow, some reactions are likely to be fast and can compete with air exchange Acetaldehyde lifetime with respect to OH in aqueous phase = 50 minutes Prior work in Turpin lab shows that outdoor collected WSOGs react with OH in minutes Svenningsson et al., 2006, Lim et al. 2013, Sareen et al. 2016
- Liquid chromatography method development Structural identification using MS-MS and confirmation with authentic standards Collection efficiency determination for specific compounds collected with mist chambers Thin films on surfaces bulk AC condensate and other bulk water
- 2 mist chambers in series and sampled for 2 hours (10 x)
- Some WSOG have been measured: HPLC, GC-MS