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

Oxidized organic aerosol (OOA) is a major component of ambient particulate matter, substantially impacting climate, human health, and ecosystems. OOA is readily produced in the presence of sunlight, and requires days of photooxidation to reach the levels observed in the atmosphere. High concentrations of OOA are thus expected in the summer; however, our current mechanistic understanding fails to explain elevated OOA during wintertime periods of low photochemical activity that coincide with periods of intense biomass burning. As a result, atmospheric models underpredict OOA concentrations by a factor of 3 to 5. Here we show that fresh emissions from biomass burning exposed to NO2 and O3 (precursors to the NO3 radical) rapidly form OOA in the laboratory over a few hours and without any sunlight. The extent of oxidation is sensitive to relative humidity. The resulting OOA chemical composition is consistent with the observed OOA in field studies in major urban areas. Additionally, this dark chemical processing leads to significant enhancements in secondary nitrate aerosol, of which 50 to 60% is estimated to be organic. Simulations that include this understanding of dark chemical processing show that over 70% of organic aerosol from biomass burning is substantially influenced by dark oxidation. This rapid and extensive dark oxidation elevates the importance of nocturnal chemistry and biomass burning as a global source of OOA.

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Night-time chemistry of biomass burning plumes in urban areas: A dual mobile chamber study

10.5194/egusphere-egu21-8469 ◽

2021 ◽

Author(s):

Spiro Jorga ◽

Kalliopi Florou ◽

Christos Kaltsonoudis ◽

John Kodros ◽

Christina Vasilakopoulou ◽

...

Keyword(s):

Biomass Burning ◽

Urban Areas ◽

Mass Spectra ◽

Prescribed Burning ◽

Organic Aerosol ◽

Photochemical Activity ◽

Organic Nitrate ◽

Night Time ◽

Starting Point ◽

High Concentrations

Biomass burning including residential heating, agricultural fires, prescribed burning, and wildfires is a major source of gaseous and particulate pollutants in the atmosphere. Although, important changes in the size distributions and the chemical composition of the biomass burning aerosol during daytime chemistry have been observed, the corresponding changes at nighttime or in winter where photochemistry is slow, have received relatively little attention. In this study, we tested the hypothesis that nightime chemistry in biomass burning plumes can be rapid in urban areas using a dual smog chamber system.&#160;Ambient urban air during winter nighttime periods with high concentrations of ambient biomass burning organic aerosol is used as the starting point. Ozone was added in the perturbed chamber to simulate mixing with background air (and subsequent NO3 production and aging) while the second chamber was used as a reference. Following the injection of ozone rapid organic aerosol (OA) formation was observed in all experiments leading to increases of the OA concentration by 20-70%. The oxygen to carbon ratio of the OA increased by 50% on average and the mass spectra of the produced OA was quite similar to that of the oxidized OA mass spectra reported during winter in urban areas. Good correlation was also observed with the produced mass spectra from nocturnal aging of laboratory biomass burning emissions showing the strong contribution of biomass burning emissions in the SOA formation during cold nights with high biomass burning activities. Concentrations of NO3 radicals as high as 25 ppt were measured in the perturbed chamber with an accompanying production of 0.2-1.2 &#956;g m-3 of organic nitrate. These results strongly indicate that the OA in biomass burning plumes can evolve rapidly even during wintertime periods with low photochemical activity.

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Nighttime chemistry of biomass burning emissions in urban areas: A dual mobile chamber study

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-15337-2021 ◽

2021 ◽

Vol 21 (19) ◽

pp. 15337-15349

Author(s):

Spiro D. Jorga ◽

Kalliopi Florou ◽

Christos Kaltsonoudis ◽

John K. Kodros ◽

Christina Vasilakopoulou ◽

...

Keyword(s):

Biomass Burning ◽

Urban Areas ◽

Mass Spectra ◽

Ambient Air ◽

Organic Aerosol ◽

Photochemical Activity ◽

Organic Nitrate ◽

Starting Point ◽

No3 Radical ◽

High Concentrations

Abstract. Residential biomass burning for heating purposes is an important source of air pollutants during winter. Here we test the hypothesis that significant secondary organic aerosol production can take place even during winter nights through oxidation of the emitted organic vapors by the nitrate (NO3) radical produced during the reaction of ozone and nitrogen oxides. We use a mobile dual smog chamber system which allows the study of chemical aging of ambient air against a control reference. Ambient urban air sampled during a wintertime campaign during nighttime periods with high concentrations of biomass burning emissions was used as the starting point for the aging experiments. Biomass burning organic aerosol (OA) was, on average, 70 % of the total OA at the beginning of our experiments. Ozone was added in the perturbed chamber to simulate mixing with background air (and subsequent NO3 radical production and aging), while the second chamber was used as a reference. Following the injection of ozone, rapid OA formation was observed in all experiments, leading to increases in the OA concentration by 20 %–70 %. The oxygen-to-carbon ratio of the OA increased on average by 50 %, and the mass spectra of the produced OA was quite similar to the oxidized OA mass spectra reported during winter in urban areas. Furthermore, good correlation was found for the OA mass spectra between the ambient-derived emissions in this study and the nocturnal aged laboratory-derived biomass burning emissions from previous work. Concentrations of NO3 radicals as high as 25 ppt (parts per trillion) were measured in the perturbed chamber, with an accompanying production of 0.1–3.2 µg m−3 of organic nitrate in the aerosol phase. Organic nitrate represented approximately 10 % of the mass of the secondary OA formed. These results strongly indicate that the OA in biomass burning plumes can chemically evolve rapidly even during wintertime periods with low photochemical activity.

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The oxidizing power of the dark side: Rapid nocturnal aging of biomass burning as an overlooked source of oxidized organic aerosol

10.5194/egusphere-egu2020-7382 ◽

2020 ◽

Author(s):

John Kodros ◽

Dimitris Papanastasiou ◽

Marco Paglione ◽

Mauro Masiol ◽

Stefania Squizzato ◽

...

Keyword(s):

Biomass Burning ◽

Urban Areas ◽

Transport Model ◽

Field Studies ◽

Organic Aerosol ◽

The United States ◽

Photochemical Activity ◽

Dark Side ◽

Ambient Atmosphere ◽

Chemical Transport Model

Oxidized organic aerosol (OOA) is a major component of ambient particulate matter, substantially affecting both climate and human health. A considerable body of evidence has established that OOA is readily produced in the presence of daylight, thus leading to the association of high concentrations of OOA in the summer or mid-afternoon. However, this current mechanistic understanding fails to explain elevated OOA concentrations during night or wintertime periods of low photochemical activity, thus leading atmospheric models to under predict OOA concentrations by a factor of 3-5. Here we show that fresh emissions from biomass burning rapidly forms OOA in the laboratory over a few hours and without any sunlight. The resulting OOA chemical composition is consistent with the observed OOA in field studies in major urban areas. To estimate the contribution of nocturnally aged OOA in the ambient atmosphere, we incorporate this nighttime-aging mechanism into a chemical-transport model and find that over much of the United States greater than 75% of the OOA formed from fresh biomass burning emissions underwent nighttime aging processes. Thus, the conceptual framework that OOA is predominantly formed in the presence of daylight fails to account for a substantial and rapid oxidation process occurring in the dark.

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Night-time chemistry of biomass burning emissions in urban areas: A dual mobile chamber study

10.5194/acp-2021-284 ◽

2021 ◽

Author(s):

Spiro Jorga ◽

Kalliopi Florou ◽

Christos Kaltsonoudis ◽

John Kodros ◽

Christina Vasilakopoulou ◽

...

Keyword(s):

Biomass Burning ◽

Urban Areas ◽

Mass Spectra ◽

Ambient Air ◽

Organic Aerosol ◽

Photochemical Activity ◽

Organic Nitrate ◽

Night Time ◽

Starting Point ◽

No3 Radical

Abstract. Residential biomass burning for heating purposes is an important source of air pollutants during winter. Here we test the hypothesis that significant secondary organic aerosol production can take place even during winter nights through oxidation of the emitted organic vapors by the nitrate (NO3) radical produced during the reaction of ozone and nitrogen oxides. We use a mobile dual smog chamber system which allows the study of chemical aging of ambient air against a control reference. Ambient urban air sampled during a wintertime campaign during night-time periods with high concentrations of biomass burning organic aerosol was used as the starting point of the aging experiments. Ozone was added in the perturbed chamber to simulate mixing with background air (and subsequent NO3 radical production and aging), while the second chamber was used as a reference. Following the injection of ozone rapid organic aerosol (OA) formation was observed in all experiments leading to increases of the OA concentration by 20–70 %. The oxygen-to-carbon ratio of the OA increased on average by 50 % and the mass spectra of the produced OA was quite similar to the oxidized OA mass spectra reported during winter in urban areas. Further, good correlation was found for the OA mass spectra between the ambient-derived emissions in this study and the nocturnal aged laboratory-derived biomass burning emissions from previous work. Concentrations of NO3 radicals as high as 25 ppt were measured in the perturbed chamber with an accompanying production of 0.1–3.2 μg m−3 of organic nitrate in the aerosol phase. These results strongly indicate that the OA in biomass burning plumes can chemically evolve rapidly even during wintertime periods with low photochemical activity.

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Simulation of the Cooking Organic Aerosol Concentration Variability in an Urban Area

10.5194/egusphere-egu21-10090 ◽

2021 ◽

Author(s):

Evangelia Siouti ◽

Ksakousti Skyllakou ◽

Ioannis Kioutsioukis ◽

Giancarlo Ciarelli ◽

Spyros N. Pandis

Keyword(s):

Urban Area ◽

Urban Areas ◽

Temporal Distribution ◽

Late Summer ◽

Field Studies ◽

Organic Aerosol ◽

Basis Set ◽

Cooking Times ◽

The City ◽

Lunch Time

Cooking operations can be an important fine PM source for urban areas. Cooking emissions are a source of pollution that has been often ignored and are not included or are seriously underestimated in urban emission inventories. However, several field studies in cities all over Europe suggest that cooking organic aerosol (COA) can be an important component of the total organic PM. In this study we propose and evaluate a methodology for the simulation of the COA concentration and its variability in space and time in an urban area. The city of Patras, the third biggest in Greece is used for this first application for a typical late summer period. The spatial distribution of COA emissions is based on the exact location of restaurants and grills, while the emissions on the meat consumption in Greece. We estimated COA emissions of 150 kg d-1 that corresponds to 0.6 g d-1 per person. The temporal distribution of COA was based on the known cooking times and the results of the past field studies in the area. Half of the daily COA is emitted during dinner time (21:00-0:00 LT), while approximately 25% during lunch time (13:00-16:00 LT). The COA is simulated using the Volatility Basis Set with a volatility distribution measured in the laboratory and is treated as semivolatile and reactive. The maximum average COA concentration during the simulation period is predicted to be 1.3 &#956;g m-3 in a mainly pedestrian area with a high density of restaurants. Peak hourly COA concentrations in this area exceed 10 &#956;g m-3 during several nights. The local production of secondary COA is predicted to be slow and it represents just a few percent of the total COA.&#160;

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Characterization of Organosulfates in Secondary Organic Aerosol Derived from the Photooxidation of Long-Chain Alkanes

10.5194/acp-2016-20 ◽

2016 ◽

Cited By ~ 1

Author(s):

M. Riva ◽

T. Da Silva Barbosa ◽

Y.-H. Lin ◽

E. A. Stone ◽

A. Gold ◽

...

Keyword(s):

Gas Phase ◽

Urban Areas ◽

Secondary Organic Aerosol ◽

Field Studies ◽

Organic Aerosol ◽

Ultra Performance Liquid Chromatography ◽

Urban Aerosol ◽

Flight Mass Spectrometry ◽

Phase Oxidation ◽

Gas Phase Oxidation

Abstract. We report the formation of aliphatic organosulfates (OSs) in secondary organic aerosol (SOA) from the photooxidation of C10 – C12 alkanes. The results complement those from our laboratories reporting the formation of OSs and sulfonates from gas-phase oxidation of polycyclic aromatic hydrocarbons (PAHs). Both studies strongly support formation of OSs from gas-phase oxidation of anthropogenic precursors, hypothesized on the basis of recent field studies in which aromatic and aliphatic OSs were detected in fine aerosol collected from several major urban locations. In this study, dodecane, cyclodecane and decalin, considered to be important SOA precursors in urban areas, were photochemically oxidized in an outdoor smog chamber in the presence of either non-acidified or acidified ammonium sulfate seed aerosol. Effects of chemical structure, acidity and relative humidity on OS formation were examined. Aerosols collected from all experiments were characterized by ultra performance liquid chromatography coupled to electrospray ionization high-resolution quadrupole time-of flight mass spectrometry (UPLC/ESI-HR-QTOFMS). Most of the OSs identified could be explained by formation of gaseous epoxide precursors with subsequent acid-catalyzed reactive uptake onto sulfate aerosol. The OSs identified here were also observed and quantified in fine urban aerosol samples collected in Lahore, Pakistan, and Pasadena, USA. Many of the OSs identified from the photooxidation of decalin and cyclodecane are isobars of known monoterpene organosulfates, and thus care must be taken in the analysis of alkane-derived organosulfates in urban aerosol.

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Chemical and physical transformations of organic aerosol from the photo-oxidation of open biomass burning emissions in an environmental chamber

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-11995-2011 ◽

2011 ◽

Vol 11 (4) ◽

pp. 11995-12037 ◽

Cited By ~ 8

Author(s):

C. J. Hennigan ◽

M. A. Miracolo ◽

G. J. Engelhart ◽

A. A. May ◽

A. A. Presto ◽

...

Keyword(s):

Biomass Burning ◽

Organic Aerosol ◽

Heterogeneous Reactions ◽

Chemical Processing ◽

Science Laboratory ◽

Enhancement Ratio ◽

Smog Chamber ◽

Photo Oxidation ◽

The Us ◽

Mass Enhancement

Abstract. Smog chamber experiments were conducted to investigate chemical and physical transformations of organic aerosol (OA) during photo-oxidation of open biomass burning emissions. The experiments were carried out at the US Forest Service's Fire Science Laboratory as part of the third Fire Lab at Missoula Experiment (FLAME III). We investigated 12 different fuels commonly burned in North American wildfires. The experiments feature atmospheric and plume aerosol and oxidant concentrations; aging times ranged from 3–4.5 h. OA production, expressed as a mass enhancement ratio (ratio of OA to primary OA (POA) mass), was highly variable. OA mass enhancement ratios ranged from 2.9 in experiments where secondary OA (SOA) production nearly tripled the POA concentration, to 0.7 in experiments where photo-oxidation resulted in a 30% loss of the OA mass. The campaign-average OA mass enhancement ratio was 1.7 ± 0.7 (mean ± 1 σ); therefore, on average, there was substantial SOA production. In every experiment, the OA was chemically transformed. Even in experiments with net loss of OA mass, the OA became increasingly oxygenated and less volatile with aging, indicating that photo-oxidation transformed the POA emissions. Levoglucosan concentrations were also substantially reduced with photo-oxidation. The transformations of POA were extensive; using levoglucosan as a tracer for POA, unreacted POA only contributed 17% of the campaign-average OA mass after 3.5 h of exposure to typical atmospheric hydroxyl radical (OH) levels. Heterogeneous reactions with OH could account for less than half of this transformation, implying that the coupled gas-particle partitioning and reaction of semi-volatile vapors is an important and potentially dominant mechanism for POA processing. Overall, the results illustrate that biomass burning emissions are subject to extensive chemical processing in the atmosphere, and the timescale for these transformations is rapid.

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Sources and production of organic aerosol in Mexico City: insights from the combination of a chemical transport model (PMCAMx-2008) and measurements during MILAGRO

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-5153-2011 ◽

2011 ◽

Vol 11 (11) ◽

pp. 5153-5168 ◽

Cited By ~ 37

Author(s):

A. P. Tsimpidi ◽

V. A. Karydis ◽

M. Zavala ◽

W. Lei ◽

N. Bei ◽

...

Keyword(s):

Mexico City ◽

Biomass Burning ◽

Urban Areas ◽

Transport Model ◽

Three Dimensional ◽

Chemical Transport ◽

Organic Aerosol ◽

Basis Set ◽

Chemical Transport Model ◽

Aerosol Mass

Abstract. Urban areas are large sources of organic aerosols and their precursors. Nevertheless, the contributions of primary (POA) and secondary organic aerosol (SOA) to the observed particulate matter levels have been difficult to quantify. In this study the three-dimensional chemical transport model PMCAMx-2008 is used to investigate the temporal and geographic variability of organic aerosol in the Mexico City Metropolitan Area (MCMA) during the MILAGRO campaign that took place in the spring of 2006. The organic module of PMCAMx-2008 includes the recently developed volatility basis-set framework in which both primary and secondary organic components are assumed to be semi-volatile and photochemically reactive and are distributed in logarithmically spaced volatility bins. The MCMA emission inventory is modified and the POA emissions are distributed by volatility based on dilution experiments. The model predictions are compared with observations from four different types of sites, an urban (T0), a suburban (T1), a rural (T2), and an elevated site in Pico de Tres Padres (PTP). The performance of the model in reproducing organic mass concentrations in these sites is encouraging. The average predicted PM1 organic aerosol (OA) concentration in T0, T1, and T2 is 18 μg m−3, 11.7 μg m−3, and 10.5 μg m−3 respectively, while the corresponding measured values are 17.2 μg m−3, 11 μg m−3, and 9 μg m−3. The average predicted locally-emitted primary OA concentrations, 4.4 μg m−3 at T0, 1.2 μg m−3 at T1 and 1.7 μg m−3 at PTP, are in reasonably good agreement with the corresponding PMF analysis estimates based on the Aerosol Mass Spectrometer (AMS) observations of 4.5, 1.3, and 2.9 μg m−3 respectively. The model reproduces reasonably well the average oxygenated OA (OOA) levels in T0 (7.5 μg m−3 predicted versus 7.5 μg m−3 measured), in T1 (6.3 μg m−3 predicted versus 4.6 μg m−3 measured) and in PTP (6.6 μg m−3 predicted versus 5.9 μg m−3 measured). The rest of the OA mass (6.1 μg m−3 and 4.2 μg m−3 in T0 and T1 respectively) is assumed to originate from biomass burning activities and is introduced to the model as part of the boundary conditions. Inside Mexico City (at T0), the locally-produced OA is predicted to be on average 60 % locally-emitted primary (POA), 6 % semi-volatile (S-SOA) and intermediate volatile (I-SOA) organic aerosol, and 34 % traditional SOA from the oxidation of VOCs (V-SOA). The average contributions of the OA components to the locally-produced OA for the entire modelling domain are predicted to be 32 % POA, 10 % S-SOA and I-SOA, and 58 % V-SOA. The long range transport from biomass burning activities and other sources in Mexico is predicted to contribute on average almost as much as the local sources during the MILAGRO period.

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Molecular Markers in Ambient Air Associated with Biomass Burning in Morelos, México

Atmosphere ◽

10.3390/atmos11050491 ◽

2020 ◽

Vol 11 (5) ◽

pp. 491

Author(s):

Mónica Ivonne Arias-Montoya ◽

Rebecca López-Márquez ◽

Mario Alfonso Murillo-Tovar ◽

Jorge Antonio Guerrero-Alvarez ◽

Josefina Vergara-Sánchez ◽

...

Keyword(s):

Biomass Burning ◽

Forest Fires ◽

Glutaric Acid ◽

Dicarboxylic Acids ◽

Ambient Air ◽

Organic Aerosol ◽

Photochemical Activity ◽

Aerodynamic Diameter ◽

Positive Correlations ◽

The City

Atmospheric particles with an aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5) were collected at two sites located in the urban area of the city of Cuernavaca (Morelos) during a season when a large number of forest fires occurred. Three dicarboxylic acids (malonic, glutaric and succinic) and levoglucosan were analyzed by liquid chromatography coupled with mass spectrometry (ESI-Q-TOF) and soluble potassium (K+) was analyzed by ion chromatography. The concentration of PM2.5 increased on the days when the highest number of forest fires occurred. A strong correlation was observed between levoglucosan and K+, confirming the hypothesis that both are tracers of biomass burning (r = 0.57, p < 0.05). Levoglucosan (average 367.6 ng m−3, Site 2) was the most abundant compound, followed by succinic acid (average 101.7 ng m−3, Site 2), glutaric acid (average 63.2 ng m−3, Site 2), and malonic acid (average 46.9 ng m−3, Site 2), respectively. The ratio of C3/C4 concentrations ranged from 0.5 to 1.2, with an average of 0.8, which suggests great photochemical activity in the Cuernavaca atmosphere. The ratio of K+/levoglucosan concentrations (0.44) indicates that open fires are the main source of these tracers. The positive correlations between PM2.5 and levoglucosan and succinic and malonic acids suggest that such compounds are contributing to secondary organic aerosol particle formation.

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Efficient alkane oxidation under combustion engine and atmospheric conditions

Communications Chemistry ◽

10.1038/s42004-020-00445-3 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Zhandong Wang ◽

Mikael Ehn ◽

Matti P. Rissanen ◽

Olga Garmash ◽

Lauriane Quéléver ◽

...

Keyword(s):

Urban Areas ◽

Combustion Engine ◽

Organic Aerosol ◽

Structural Features ◽

Oxidation Products ◽

Combustion Engines ◽

Atmospheric Conditions ◽

High Concentrations ◽

Oxidation Chemistry ◽

Combustion Processes

AbstractOxidation chemistry controls both combustion processes and the atmospheric transformation of volatile emissions. In combustion engines, radical species undergo isomerization reactions that allow fast addition of O2. This chain reaction, termed autoxidation, is enabled by high engine temperatures, but has recently been also identified as an important source for highly oxygenated species in the atmosphere, forming organic aerosol. Conventional knowledge suggests that atmospheric autoxidation requires suitable structural features, like double bonds or oxygen-containing moieties, in the precursors. With neither of these functionalities, alkanes, the primary fuel type in combustion engines and an important class of urban trace gases, are thought to have minor susceptibility to extensive autoxidation. Here, utilizing state-of-the-art mass spectrometry, measuring both radicals and oxidation products, we show that alkanes undergo autoxidation much more efficiently than previously thought, both under atmospheric and combustion conditions. Even at high concentrations of NOX, which typically rapidly terminates autoxidation in urban areas, the studied C6–C10 alkanes produce considerable amounts of highly oxygenated products that can contribute to urban organic aerosol. The results of this inter-disciplinary effort provide crucial information on oxidation processes in both combustion engines and the atmosphere, with direct implications for engine efficiency and urban air quality.

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