OH chemistry of non-methane organic gases (NMOGs) emitted from laboratory and ambient biomass burning smoke: evaluating the influence of furans and oxygenated aromatics on ozone and secondary NMOG formation

Atmospheric chemistry and physics, Journal Year: 2019, Volume and Issue: 19(23), P. 14875 - 14899

Published: Dec. 10, 2019

Abstract. Chamber oxidation experiments conducted at the Fire Sciences Laboratory in 2016 are evaluated to identify important chemical processes contributing hydroxy radical (OH) chemistry of biomass burning non-methane organic gases (NMOGs). Based on decay primary carbon measured by proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS), it is confirmed that furans and oxygenated aromatics among NMOGs emitted from western United States fuel types with highest reactivities towards OH. The formation secondary NMOG masses PTR-ToF-MS iodide-clustering ionization (I-CIMS) interpreted using a box model employing modified version Master Chemical Mechanism (v. 3.3.1) includes OH furan, 2-methylfuran, 2,5-dimethylfuran, furfural, 5-methylfurfural, guaiacol. supports assignment major I-CIMS signals series anhydrides furanones formed primarily through furan chemistry. This mechanism applied Lagrangian used previously real plume. customized reproduces NMOGs, such as maleic anhydride. simulations without furans, estimated contributed up 10 % ozone over 90 anhydride within first 4 h oxidation. It shown present plume transported several days, which demonstrates utility markers for aged plumes.

Language: Английский

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Rapid dark aging of biomass burning as an overlooked source of oxidized organic aerosol

Proceedings of the National Academy of Sciences, Journal Year: 2020, Volume and Issue: 117(52), P. 33028 - 33033

Published: Dec. 14, 2020

Significance To quantify the full implications of biomass burning emissions on atmosphere, it is essential to accurately represent emission plume after has undergone chemical aging in atmosphere. Atmospheric models typically consider predominant pathway take place presence sunlight (via OH radical); however, this mechanism leads consistent underpredictions oxidized organic aerosol wintertime urban areas. Here, we show, through a combination laboratory experiments, ambient field measurements, and transport modeling, that plumes exposed NO 2 O 3 age rapidly without requiring any sunlight, thus providing an overlooked source previously not accounted for models.

Language: Английский

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Oxygen Vacancy-Governed Opposite Catalytic Performance for C₃H₆ and C₃H₈ Combustion: The Effect of the Pt Electronic Structure and Chemisorbed Oxygen Species

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(5), P. 3245 - 3257

Published: Jan. 10, 2022

Revealing the role of engineered surface oxygen vacancies in catalytic degradation volatile organic compounds (VOCs) is importance for development highly efficient catalysts. However, because various structures VOC molecules, different reactions remains ambiguous. Herein, a defective Pt/TiO2–x catalyst proposed to uncover mechanisms C3H6 and C3H8 combustion via experiments theoretical calculations. The electron transfer, originated from vacancy, facilitates formation reduced Pt0 species simultaneously interfacial chemisorbed O2, thus promoting C═C cleavage. Pt nanoparticles facilitate robust chemisorption bridging dimer O22– (Pt–O–O–Ti) species. This inhibits by depressing adsorption. work offers insights rational design catalysts activating bond alkene or C–H alkane.

Language: Английский

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New insights into the photo-degraded polystyrene microplastic: Effect on the release of volatile organic compounds

Journal of Hazardous Materials, Journal Year: 2022, Volume and Issue: 431, P. 128523 - 128523

Published: Feb. 24, 2022

Language: Английский

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Overview of the Alaskan Layered Pollution and Chemical Analysis (ALPACA) Field Experiment

ACS ES&T Air, Journal Year: 2024, Volume and Issue: 1(3), P. 200 - 222

Published: Feb. 21, 2024

The Alaskan Layered Pollution And Chemical Analysis (ALPACA) field experiment was a collaborative study designed to improve understanding of pollution sources and chemical processes during winter (cold climate low-photochemical activity), investigate indoor pollution, dispersion as affected by frequent temperature inversions. A number the research goals were motivated questions raised residents Fairbanks, Alaska, where held. This paper describes measurement strategies conditions encountered January February 2022 experiment, reports early examples how measurements addressed goals, particularly those interest residents. Outdoor air showed high concentrations particulate matter pollutant gases including volatile organic carbon species. During events, low winds extremely stable atmospheric trapped below 73 m, an shallow vertical scale. Tethered-balloon-based intercepted plumes aloft, which associated with power plant point through transport modeling. Because cold spend much their time indoors, included quality component, made inside outside house infiltration sources. In absence activities such cooking and/or heating pellet stove, lower than outdoors; however, stove burns often caused higher outdoors. mass-normalized oxidative potential, health-relevant property measured here reactivity dithiothreiol, particles varied source, having less potential per mass particles.

Language: Английский

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Nighttime Chemical Transformation in Biomass Burning Plumes: A Box Model Analysis Initialized with Aircraft Observations

Environmental Science & Technology, Journal Year: 2019, Volume and Issue: 53(5), P. 2529 - 2538

Published: Jan. 30, 2019

Biomass burning (BB) is a large source of reactive compounds in the atmosphere. While daytime photochemistry BB emissions has been studied some detail, there little focus on nighttime reactions despite potential for substantial oxidative and heterogeneous chemistry. Here, we present first analysis aircraft intercepts agricultural plumes using observations from NOAA WP-3D during 2013 Southeast Nexus (SENEX) campaign. We use these conjunction with detailed chemical box modeling to investigate formation fate oxidants (NO3, N2O5, O3, OH) volatile organic (BBVOCs), representative burns (rice straw) western wildfires (ponderosa pine). Field suggest NO3 production was approximately 1 ppbv hr-1, while N2O5 were at or below 3 pptv, indicating rapid NO3/N2O5 reactivity. Model shows that >99% loss due BBVOC + rather than aerosol uptake N2O5. Nighttime oxidation rice straw ponderosa pine fires dominated by (72, 53%, respectively) but O3 significant (25, 43%), leading roughly 55% overnight depletion most BBVOCs NO2.

Language: Английский

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Nighttime and daytime dark oxidation chemistry in wildfire plumes: an observation and model analysis of FIREX-AQ aircraft data

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(21), P. 16293 - 16317

Published: Nov. 8, 2021

Abstract. Wildfires are increasing in size across the western US, leading to increases human smoke exposure and associated negative health impacts. The impact of biomass burning (BB) smoke, including wildfires, on regional air quality depends emissions, transport, chemistry, oxidation emitted BB volatile organic compounds (BBVOCs) by hydroxyl radical (OH), nitrate (NO3), ozone (O3). During daytime, when light penetrates plumes, BBVOCs oxidized mainly O3 OH. In contrast, at night or optically dense NO3. This work focuses transition between daytime nighttime oxidation, which has significant implications for formation secondary pollutants loss nitrogen oxides (NOx=NO+NO2) been understudied. We present wildfire plume observations made during FIREX-AQ (Fire Influence Regional Global Environments Air Quality), a field campaign involving multiple aircraft, ground, satellite, mobile platforms that took place United States summer 2019 study both agricultural emissions atmospheric chemistry. use from two research NASA DC-8 NOAA Twin Otter, with detailed chemical box model, updated phenolic mechanisms, analyze sampled midday, sunset, nighttime. Aircraft suggest range NO3 production rates (0.1–1.5 ppbv h−1) plumes transported midday after dark. Modeled initial instantaneous reactivity toward NO3, OH, is 80.1 %, 87.7 99.6 respectively. Initial 10–104 times greater than typical values forested urban environments, reactions account >97 % sunlit (jNO2 up 4×10-3s-1), while conventional photochemical through reaction NO photolysis minor pathways. Alkenes furans mostly OH (11 %–43 54 %–88 alkenes; 18 %–55 39 %–76 furans, respectively), but split O3, (26 %–52 22 16 %–33 respectively). Nitrate accounts 26 sunset an thick plume. Nitrocatechol yields varied 33 45 chemistry late day responsible 72 %–92 (84 plume) nitrocatechol controls nitrophenolic overall. As result, overnight pathways 56 %±2 NOx sunrise following day. all one we modeled, there was remaining (13 %–57 %) (8 %–72 sunrise.

Language: Английский

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Emissions of non-methane volatile organic compounds from combustion of domestic fuels in Delhi, India

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(4), P. 2383 - 2406

Published: Feb. 18, 2021

Abstract. Twenty-nine different fuel types used in residential dwellings northern India were collected from across Delhi (76 samples total). Emission factors of a wide range non-methane volatile organic compounds (NMVOCs) (192 total) measured during controlled burning experiments using dual-channel gas chromatography with flame ionisation detection (DC-GC-FID), two-dimensional (GC × GC-FID), proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) and solid-phase extraction (SPE-GC GC–ToF-MS). On average, 94 % speciation total NMVOC emissions was achieved all types. The largest contributors to most small non-aromatic oxygenated species, phenolics furanics. emission (in g kg−1) for gas-phase NMVOCs fuelwood (18.7, 4.3–96.7), cow dung cake (62.0, 35.3–83.0), crop residue (37.9, 8.9–73.8), charcoal (5.4, 2.4–7.9), sawdust (72.4, 28.6–115.5), municipal solid waste (87.3, 56.6–119.1) liquefied petroleum (5.7, 1.9–9.8). this study allow better characterisation, evaluation understanding the air quality impacts solid-fuel combustion India.

Language: Английский

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Emissions of intermediate-volatility and semi-volatile organic compounds from domestic fuels used in Delhi, India

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(4), P. 2407 - 2426

Published: Feb. 18, 2021

Abstract. Biomass burning emits significant quantities of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) in a complex mixture, probably containing many thousands chemical species. These components are significantly more toxic have poorly understood chemistry compared to volatile routinely quantified ambient air; however, analysis I/SVOCs presents difficult analytical challenge. The gases particles emitted during the test combustion range domestic solid fuels collected from across Delhi were sampled analysed. Organic aerosol was onto Teflon (PTFE) filters, residual low-volatility adsorbed surface solid-phase extraction (SPE) discs. A new method relying on accelerated solvent (ASE) coupled comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC–ToF-MS) developed. This highly sensitive powerful technique enabled over 3000 peaks I/SVOC species unique spectra be detected. total 15 %–100 % gas-phase emissions 7 particle-phase characterised. analysed for suitability make quantitative measurements using SPE Analysis discs indicated phenolic furanic important levoglucosan phase. Gas- emission factors 21 polycyclic aromatic hydrocarbons (PAHs) derived, including 16 listed by US EPA as priority pollutants. Gas-phase dominated smaller PAHs. measured (mg kg−1) PAHs cow dung cake (615), municipal waste (1022), crop residue (747), sawdust (1236), fuelwood (247), charcoal (151) liquefied petroleum (56). results this study indicate that likely PAH sources, further is required quantify their impact alongside burning.

Language: Английский

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Atmospheric organic vapors in two European pine forests measured by a Vocus PTR-TOF: insights into monoterpene and sesquiterpene oxidation processes

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(5), P. 4123 - 4147

Published: March 18, 2021

Abstract. Atmospheric organic vapors play essential roles in the formation of secondary aerosol. Source identification these is thus fundamental to understanding their emission sources and chemical evolution atmosphere further impact on air quality climate change. In this study, a Vocus proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF) was deployed two forested environments, Landes forest southern France boreal Finland, measure atmospheric vapors, including both volatile compounds (VOCs) oxidation products. For first time, we performed binned positive matrix factorization (binPMF) analysis complex spectra acquired with PTR-TOF identified various as well processes atmosphere. Based separate low- high-mass ranges, 15 PMF factors nine Finnish were resolved, showing high similarity between sites. Particularly, terpenes terpene reaction products separated into individual varying degrees, such lightly oxidized from monoterpene sesquiterpene oxidation, monoterpene-derived nitrates, more compounds. Factors representing monoterpenes dominated biogenic VOCs forests, lower contributions isoprene factors. products, nitrates monoterpenes/sesquiterpenes accounted for 8 %–12 % measured gas-phase forests. interpretation results relating processes, insights gained regarding reactions. example, strong relative humidity (RH) dependence found behavior High concentrations only occur at RH; yet similar not observed

Language: Английский

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