Effects of anthropogenic emissions on aerosol formation from isoprene and monoterpenes in the southeastern United States

Xu, Lu; Guo, Hongyu; Boyd, Christopher M.; Klein, Mitchel; Bougiatioti, A.; Cerully, K. M.; Hite, J. R.; Isaacman-VanWertz, Gabriel; Kreisberg, N. M.; Knote, Christoph; Olson, K. F.; Koss, A.; Goldstein, Allen H.; Hering, Susanne V.; Gouw, J. A. de; Baumann, Karsten; Lee, Shan‐Hu; Nenes, Athanasios; Weber, R. J.; Ng, N. L.

doi:10.1073/pnas.1417609112

Cited by 569 publications

(900 citation statements)

References 46 publications

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“…Site description and instruments involved during the SOAS campaign are detailed elsewhere (8,(16)(17)(18). Ambient air was continuously drawn with mechanical pumps through two inlets.…”

Section: Methodsmentioning

confidence: 99%

Highly functionalized organic nitrates in the southeast United States: Contribution to secondary organic aerosol and reactive nitrogen budgets

Lee

Mohr

Lopez‐Hilfiker

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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305

438

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Speciated particle-phase organic nitrates (pONs) were quantified using online chemical ionization MS during June and July of 2013 in rural Alabama as part of the Southern Oxidant and Aerosol Study. A large fraction of pONs is highly functionalized, possessing between six and eight oxygen atoms within each carbon number group, and is not the common first generation alkyl nitrates previously reported. Using calibrations for isoprene hydroxynitrates and the measured molecular compositions, we estimate that pONs account for 3% and 8% of total submicrometer organic aerosol mass, on average, during the day and night, respectively. Each of the isoprene-and monoterpenes-derived groups exhibited a strong diel trend consistent with the emission patterns of likely biogenic hydrocarbon precursors. An observationally constrained diel box model can replicate the observed pON assuming that pONs (i) are produced in the gas phase and rapidly establish gasparticle equilibrium and (ii) have a short particle-phase lifetime (∼2-4 h). Such dynamic behavior has significant implications for the production and phase partitioning of pONs, organic aerosol mass, and reactive nitrogen speciation in a forested environment. O rganic nitrates (ONs; ON = RONO 2 + RO 2 NO 2 ) are an important reservoir, if not sink, of atmospheric nitrogen oxides (NO x = NO + NO 2 ). ONs formed from isoprene oxidation alone are responsible for the export of 8-30% of anthropogenic NO x out of the US continental boundary layer (1, 2). Regional NO x budgets and tropospheric ozone (O 3 ) production are, therefore, particularly sensitive to uncertainties in the yields and fates of ON (3-6). The yields implemented in modeling studies are determined from laboratory experiments, in which only a few of the first generation gaseous ONs or the total gas-phase ONs and particle-phase organic nitrates (pONs) have been quantified, whereas production of highly functionalized ONs capable of strongly partitioning to the particle phase have been inferred (7-11) or directly measured in the gas phase (12). Addition of a nitrate (-ONO 2 ) functional group to a hydrocarbon is estimated to lower the equilibrium saturation vapor pressure by 2.5-3 orders of magnitude (13). Thus, ON formation can enhance particle-phase partitioning of semivolatile species in regions with elevated levels of nitrogen oxides, contributing to secondary organic aerosol (SOA) growth (8). However, highly time-resolved measurements of speciated ON in the particle phase have been lacking.We use a recently developed high-resolution time-of-flight chemical ionization mass spectrometer (HRToF-CIMS) using iodide-adduct ionization (14) with a filter inlet for gases and aerosols (FIGAERO) (15) that allows alternating in situ measurements of the molecular SignificanceWe present online field observations of the speciated molecular composition of organic nitrates in ambient atmospheric particles utilizing recently developed high-resolution MS-based instrumentation. We find that never-before-identified low-volatility organi...

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“…Site description and instruments involved during the SOAS campaign are detailed elsewhere (8,(16)(17)(18). Ambient air was continuously drawn with mechanical pumps through two inlets.…”

Section: Methodsmentioning

confidence: 99%

Highly functionalized organic nitrates in the southeast United States: Contribution to secondary organic aerosol and reactive nitrogen budgets

Lee

Mohr

Lopez‐Hilfiker

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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305

438

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“…24 Other sources of OA, including isoprene epoxydiols-derived SOA (IEPOX-SOA), monoterpene-derived SOA, and biomass burning OA (BBOA), are also resolved out concurrent with ISOPOOH-SOA, consistent with published PMF results for this study and site from another group. 25 …”

Section: S7mentioning

confidence: 99%

Formation of Low Volatility Organic Compounds and Secondary Organic Aerosol from Isoprene Hydroxyhydroperoxide Low-NO Oxidation

Krechmer

Coggon

Massoli

et al. 2015

Environ. Sci. Technol.

200

276

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Gas-phase low volatility organic compounds (LVOC), produced from oxidation of isoprene 4-hydroxy-3-hydroperoxide (4,3-ISOPOOH) under low-NO conditions, were observed during the FIXCIT chamber study. Decreases in LVOC directly correspond to appearance and growth in secondary organic aerosol (SOA) of consistent elemental composition, indicating that LVOC condense (at OA below 1 μg m–3). This represents the first simultaneous measurement of condensing low volatility species from isoprene oxidation in both the gas and particle phases. The SOA formation in this study is separate from previously described isoprene epoxydiol (IEPOX) uptake. Assigning all condensing LVOC signals to 4,3-ISOPOOH oxidation in the chamber study implies a wall-loss corrected non-IEPOX SOA mass yield of ∼4%. By contrast to monoterpene oxidation, in which extremely low volatility VOC (ELVOC) constitute the organic aerosol, in the isoprene system LVOC with saturation concentrations from 10–2 to 10 μg m–3 are the main constituents. These LVOC may be important for the growth of nanoparticles in environments with low OA concentrations. LVOC observed in the chamber were also observed in the atmosphere during SOAS-2013 in the Southeastern United States, with the expected diurnal cycle. This previously uncharacterized aerosol formation pathway could account for ∼5.0 Tg yr–1 of SOA production, or 3.3% of global SOA.

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“…Isoprene chemistry also affects global climate primarily through the formation of secondary organic aerosol (SOA). [4][5][6][7] However, the lingering uncertainties of SOA formation in various anthropogenically-impacted, but biogenically-influenced, systems preclude accurate simulations of human-induced climate and air quality feedbacks in atmospheric chemical transport models.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of the hydroxyl radical oxidation of methacryloyl peroxynitrate (MPAN) and its pathway toward secondary organic aerosol formation in the atmosphere

Nguyen

Bates

Crounse

et al. 2015

Phys. Chem. Chem. Phys.

120

156

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Methacryloyl peroxynitrate (MPAN), the acyl peroxynitrate of methacrolein, has been suggested to be an important secondary organic aerosol (SOA) precursor from isoprene oxidation. Yet, the mechanism by which MPAN produces SOA through reaction with the hydroxyl radical (OH) is unclear. We systematically evaluate three proposed mechanisms in controlled chamber experiments and provide the first experimental support for the theoretically-predicted lactone formation pathway from the MPAN + OH reaction, producing hydroxymethyl-methyl-a-lactone (HMML). The decomposition of the MPAN-OH adduct yields HMML + NO 3 (B75%) and hydroxyacetone + CO + NO 3 (B25%), out-competing its reaction with atmospheric oxygen. The production of other proposed SOA precursors, e.g., methacrylic acid epoxide (MAE), from MPAN and methacrolein are negligible (o2%). Furthermore, we show that the beta-alkenyl moiety of MPAN is critical for lactone formation. Alkyl radicals formed cold via H-abstraction by OH do not decompose to HMML, even if they are structurally identical to the MPAN-OH adduct. The SOA formation from HMML, from polyaddition of the lactone to organic compounds at the particle interface or in the condensed phase, is close to unity under dry conditions. However, the SOA yield is sensitive to particle liquid water and solvated ions. In hydrated inorganic particles, HMML reacts primarily with H 2 O to produce the monomeric 2-methylglyceric acid (2MGA) or with aqueous sulfate and nitrate to produce the associated organosulfate and organonitrate, respectively. 2MGA, a tracer for isoprene SOA, is semivolatile and its accommodation in aerosol water decreases with decreasing pH. Conditions that enhance the production of neutral 2MGA suppress SOA mass from the HMML channel. Considering the liquid water content and pH ranges of ambient particles, 2MGA will exist largely as a gaseous compound in some parts of the atmosphere.

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Effects of anthropogenic emissions on aerosol formation from isoprene and monoterpenes in the southeastern United States

Cited by 569 publications

References 46 publications

Highly functionalized organic nitrates in the southeast United States: Contribution to secondary organic aerosol and reactive nitrogen budgets

Highly functionalized organic nitrates in the southeast United States: Contribution to secondary organic aerosol and reactive nitrogen budgets

Formation of Low Volatility Organic Compounds and Secondary Organic Aerosol from Isoprene Hydroxyhydroperoxide Low-NO Oxidation

Mechanism of the hydroxyl radical oxidation of methacryloyl peroxynitrate (MPAN) and its pathway toward secondary organic aerosol formation in the atmosphere

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