Final Report: Emission, Fate, and Contribution of Biogenic Volatile Organic Compounds to Organic Aerosol Formation in the Presence of Anthropogenic Pollution: Measurements and Modeling during SOAS

EPA Grant Number: R835407
Title: Emission, Fate, and Contribution of Biogenic Volatile Organic Compounds to Organic Aerosol Formation in the Presence of Anthropogenic Pollution: Measurements and Modeling during SOAS
Investigators: Mak, John E , Goldstein, Allen H. , Guenther, Alex
Institution: The State University of New York at Stony Brook , National Center for Atmospheric Research , University of California - Berkeley
EPA Project Officer: Hunt, Sherri
Project Period: April 1, 2013 through March 31, 2016
Project Amount: $399,964
RFA: Anthropogenic Influences on Organic Aerosol Formation and Regional Climate Implications (2012) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Global Climate Change , Climate Change , Air

Objective:

The overall goal of this project was to quantify BVOC emission and VOC deposition to terrestrial ecosystems and characterize VOC atmospheric oxidation and the impact of anthropogenic pollution on secondary organic aerosol (SOA) formation. The specific objectives include:

  1. Constrain and understand the processes controlling BVOC emission, atmospheric oxidation and deposition;
  2. Elucidate the oxidation pathways of primary organics to form secondary organics in clean and polluted atmospheric conditions;
  3. Evaluate the relative contributions of biogenic and anthropogenic emissions to the regional SOA burden in the southeastern United States;
  4. Search for previously unidentified/unmeasured semi-volatile organic compounds (SVOCs) that would help explain why observations of SOA are often up to an order of magnitude higher than traditional models predict;
  5. Investigate the impacts of urban development patterns on biogenic and anthropogenic emissions and determine the implications for regional climate.

These objectives will provide policy-makers with needed tools to improve model representations of anthropogenic influences on organic aerosol formation and regional climate implications.

Summary/Accomplishments (Outputs/Outcomes):

The chemical composition of gases and particles in the atmosphere is driven by emissions from the earth’s surface. Anthropogenic emissions are now a major perturbation to the global environment but terrestrial ecosystems continue to be important sources and sinks of reactive carbon, nitrogen and oxidants. The potential importance of terrestrial ecosystem emissions has been demonstrated by modeling studies but a quantitative understanding is lacking and there is evidence that some key biogenic compounds have yet to be identified. As a result, our ability to simulate land-atmosphere emission and deposition is inadequate and the results from this project have contribute to reducing the overall uncertainties in predicting future air quality and climate.

We coordinated an unprecedented comprehensive suite of ecosystem-atmosphere flux measurements on leaf, canopy, landscape and regional scales. Instruments based on a mobile lift, above canopy towers and light aircraft platforms directly measured fluxes across leaf, canopy and landscape scales were deployed at two representative forests; an upland forest at the Centreville site and a lowland forest at the AABC site. The processes investigated by these local scale measurements were complemented by a VOC gradient measurements system on a light aircraft along with flux measurement systems on the NCAR C130 aircraft that, along with satellite observations, extend our land-atmosphere exchange measurements to most of the major ecosystems across the southeastern United States. The campaign included comprehensive observations of VOCs and other trace gases (e.g., O3, NOx , and HOx) from airborne and ground-based platforms (Hidy et al., 2014). This allowed us to investigate the photochemistry of isoprene based on both ground-based and airborne observations during the SAS campaign (Lu et al., 2016). The experiment layout is shown in Figure 1, which also includes a schematic of the important processes controlling the diurnal evolution of chemical species in the boundary layer.

Vertical profiles of VOCs were quantified with airborne sampling and subsequent measurements by using a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS). Ground-based eddy covariance (EC) was used to measure VOC fluxes on a tower above the forest canopy. A mixed-layer chemistry model was used to study how different processes (entrainment, boundary layer dynamics, surface emission, deposition, chemical production and loss) control the evolution of trace gases inside the CBL. The observations were used to impose the early morning initial conditions and the surface/free-tropospheric boundary conditions. This enabled us to developed a better understanding of isoprene photochemistry by focusing on the fate of ISOPOO radicals under different NO : HO2 values.

Our comprehensive measurements of leaf, canopy and landscape-level isoprene and monoterpene concentrations and emissions at the two SAS tower sites present a unique opportunity to constrain the processes controlling BVOC emissions in this region. The earlier SOS studies included only leaf level emission measurements that represented just a small fraction of the ecosystem and were extrapolated to the canopy scale to predict fluxes into the above canopy atmosphere. The magnitude and diurnal variations of whole canopy isoprene and monoterpene emissions measured during SAS compare well with both the extrapolation of leaf level results and with vertical concentration profiles measured from the canopy to the top of the boundary layer (Su et al., 2016). The extensive eddy covariance isoprene and monoterpene measurements conducted during the NCAR C130 flights, and the complementary measurements from the NOAA P3 flights, extend these constraints to other southeastern US ecosystems.

The WASP VOC sampling system enabled us to quantify the vertical profiles of VOC species inside the CBL at high temporal (hourly) resolution. Before sunrise, isoprene and MVK + MACR exhibit lower mixing ratios (< 1.00 ppbv) within and above the CBL. This is due to the absence of solar radiation, which drives biological isoprene production, and convective turbulent mixing. Monoterpenes, on the other hand, have a large contrast in mixing ratios within and above the CBL in early morning. This is largely attributed to nighttime emissions and a lack of vertical turbulent mixing, trapping the monoterpenes within the nocturnal boundary layer’s limited depth. During sunlit noontime, observed vertical profiles of isoprene and monoterpenes reveal a vertical gradient within the CBL, with higher mixing ratios near the forest canopy and low values towards the top of the CBL. The MXLCH model generally reproduces the boundary layer’s diurnal evolution (e.g., BLH growth, potential temperature, and specific humidity). Accurate modeling of BLH is essential for investigating trace-gas photochemistry in that the FT–CBL exchange plays an important role in regulating the vertical distribution and evolution of trace-gas species in the CBL through entrainment.

Budget analyses show that the diurnal evolution of O3 is mainly controlled by entrainment. Isoprene photochemistry is strongly influenced by NO:HO2 values. This is reflected through the fate of ISOPOO radicals, which shift from a NO-dominant pathway (with a contribution of 93 %) to a NO-HO2-balanced pathway (with a contribution of 54 %) from early morning (NO : HO2 = 163) to noontime (NO : HO2 = 1). As a result, ISOPN and ISOPOOH show peaks during 09:00 CST and 16:00 CST, respectively. ISOPN production is constrained by isoprene before 09:00 CST. The mixing ratio of ISOPN decreases after 09:00 CST due to its short lifetime (2 h) and limited NO availability. ISOPOOH is inversely correlated with NO:HO2. Model outputs significantly overestimate ISOPOOH mixing ratios in the late afternoon when compared with ground-based observation, with implications for missing sinks of ISOPOOH.

 


Journal Articles on this Report : 7 Displayed | Download in RIS Format

Other project views: All 14 publications 8 publications in selected types All 8 journal articles
Type Citation Project Document Sources
Journal Article Kaiser J, Skog KM, Baumann K, Bertman SB, Brown SB, Brune WH, Crounse, JD, de Gouw, JA, Edgerton, ES, Feiner PA, Goldstein AH, Koss A, Misztal PK, Nguyen TB, Olson KF, St. Clair JM, Teng AP, Toma S, Wennberg PO, Wild RJ, Zhang L, Keutsch FN. Speciation of OH reactivity above the canopy of an isoprene-dominated forest. Atmospheric Chemistry and Physics 2016;16(14):9349-9359. R835407 (Final)
R835406 (Final)
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  • Journal Article Kaser L, Karl T, Yuan B, Mauldin III RL, Cantrell CA, Guenther AB, Patton EG, Weinheimer AJ, Knote C, Orlando J, Emmons L, Apel E, Hornbrook R, Shertz S, Ullmann K, Hall S, Graus M, de Gouw J, Zhou X, Ye C. Chemistry-turbulence interactions and mesoscale variability influence the cleansing efficiency of the atmosphere. Geophysical Research Letters 2015;42(24):10894-10903. R835407 (2014)
    R835407 (Final)
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  • Journal Article Lee BH, Mohr C, Lopez-Hilfiker FD, Lutz A, Hallquist M, Lee L, Romer P, Cohen RC, Iyer S, Kurten T, Hu W, Day DA, Campuzano-Jost P, Jimenez JL, Xu L, Ng NL, Guo H, Weber RJ, Wild RJ, Brown SS, Koss A, de Gouw J, Olson K, Goldstein AH, Seco R, Kim S, McAvey K, Shepson PB, Starn T, Baumann K, Edgerton ES, Liu J, Shilling JE, Miller DO, Brune W, Schobesberger S, D'Ambro EL, Thornton JA. Highly functionalized organic nitrates in the southeast United States: contribution to secondary organic aerosol and reactive nitrogen budgets. Proceedings of the National Academy of Sciences of the United States of America 2016;113(6):1516-1521. R835407 (Final)
    R835400 (2014)
    R835400 (Final)
    R835403 (2015)
    R835403 (Final)
    R835410 (2013)
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  • Journal Article Misztal PK, Hewitt CN, Wildt J, Blande JD, Eller ASD, Fares S, Gentner DR, Gilman JB, Graus M, Greenberg J, Guenther AB, Hansel A, Harley P, Huang M, Jardine K, Karl T, Kaser L, Keutsch FN, Kiendler-Scharr A, Kleist E, Lerner BM, Li T, Mak J, Nolscher AC, Schnitzhofer R, Sinha V, Thornton B, Warneke C, Wegener F, Werner C, Williams J, Worton DR, Yassaa N, Goldstein AH. Atmospheric benzenoid emissions from plants rival those from fossil fuels. Scientific Reports 2015;5:12064 (10 pp.). R835407 (2014)
    R835407 (Final)
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  • Journal Article Pye HOT, Murphy BN, Xu L, Ng NL, Carlton AG, Guo H, Weber R, Vasilakos P, Appel KW, Budisulistiorini SH, Surratt JD, Nenes A, Hu W, Jimenez JL, Isaacman-VanWertz G, Misztal PK, Goldstein AH. On the implications of aerosol liquid water and phase separation for organic aerosol mass. Atmospheric Chemistry and Physics 2017;17(1):343-369. R835407 (Final)
    R835403 (2015)
    R835403 (Final)
    R835404 (2015)
    R835404 (Final)
    R835877 (2016)
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  • Journal Article Romer PS, Duffey KC, Wooldridge PJ, Allen HM, Ayres BR, Brown SS, Brune WH, Crounse JD, de Gouw J, Draper DC, Feiner PA, Fry JL, Goldstein AH, Koss A, Misztal PK, Nguyen TB, Olson K, Teng AP, Wennberg PO, Wild RJ, Zhang L, Cohen RC. The lifetime of nitrogen oxides in an isoprene-dominated forest. Atmospheric Chemistry and Physics 2016;16(12):7623-7637. R835407 (Final)
    R835399 (Final)
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  • Journal Article Yuan B, Kaser L, Karl T, Graus M, Peischl J, Campos TL, Shertz S, Apel EC, Hornbrook RS, Hills A, Gilman JB, Lerner BM, Warneke C, Flocke FM, Ryerson TB, Guenther AB, De Gouw JA. Airborne flux measurements of methane and volatile organic compounds over the Haynesville and Marcellus shale gas production regions. Journal of Geophysical ResearchAtmospheres 2015;120(12):6271-6289. R835407 (Final)
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  • Supplemental Keywords:

    Isoprene, biogenic emissions, fluxes, monoterpenes, MEGAN;

    Relevant Websites:

    SOAS - Integrated Surface Flux System (ISFS) | NCAR UCAR Earth Observing Laboratory
    SOAS - Integrated Sounding System (ISS) | NCAR UCAR Earth Observing Laboratory
    SOAS | NCAR UCAR Earth Observing Laboratory
    SOAS - AABC | NCAR UCAR Earth Observing Laboratory
    SEARCH-CTR | NCAR UCAR Earth Observing Laboratory

    Progress and Final Reports:

    Original Abstract
    2013 Progress Report
    2014 Progress Report