Molecular composition of organic aerosols in central Amazonia: an
ultra-high-resolution mass spectrometry study

Kourtchev, Ivan; Godoi, Ricardo H. M.; Connors, Sarah; Levine, J. G.; Archibald, Alexander T.; Godoi, Ana F. L.; Paralovo, Sarah Lima; Barbosa, Cybelli G. G.; Souza, Rodrigo Augusto Ferreira de; Manzi, A. O.; Seco, Roger; Sjostedt, S. J.; Park, Jeong‐Hoo; Guenther, Alex; Kim, Saewung; Smith, James N.; Martin, Scot T.; Kalberer, Markus

doi:10.5194/acp-16-11899-2016

Cited by 90 publications

(94 citation statements)

References 87 publications

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“…The T3 site of GoAmazon2014/5 was chosen because it was expected (and was shown in Kourtchev et al, 2016) to be impacted by multiple distinct types of emissions. These include regional biogenic emissions (isoprene, MT, SQT, etc.…”

Section: Estimating Source Contributions To Potential Soa Using Multimentioning

confidence: 99%

“…Oxidation of ambient forest air dominated by biogenic emissions and urban air dominated by urban emissions has shown that ambient S/IVOCs are likely impor-tant precursors for ambient SOA formation from OH oxidation, but not for O 3 or NO 3 oxidation . In contrast to those locations, the atmosphere in the Central Amazon forest (downwind of Manaus) is influenced by mixed biogenic, urban, and biomass burning sources of SOA precursor gases Kourtchev et al, 2016), providing a unique opportunity to study the influence of anthropogenic activities on the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Secondary organic aerosol formation from ambient air in an oxidation flow reactor in central Amazonia

Palm¹,

Sá²,

Day³

et al. 2018

Atmos. Chem. Phys.

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Abstract. Secondary organic aerosol (SOA) formation from ambient air was studied using an oxidation flow reactor (OFR) coupled to an aerosol mass spectrometer (AMS) during both the wet and dry seasons at the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) field campaign. Measurements were made at two sites downwind of the city of Manaus, Brazil. Ambient air was oxidized in the OFR using variable concentrations of either OH or O 3 , over ranges from hours to days (O 3 ) or weeks (OH) of equivalent atmospheric aging. The amount of SOA formed in the OFR ranged from 0 to as much as 10 µg m −3 , depending on the amount of SOA precursor gases in ambient air. Typically, more SOA was formed during nighttime than daytime, and more from OH than from O 3 oxidation. SOA yields of individual organic precursors under OFR conditions were measured by standard addition into ambient air and were confirmed to be consistent with published environmental chamber-derived SOA yields. Positive matrix factorization of organic aerosol (OA) after OH oxidation showed formation of typical oxidized OA factors and a loss of primary Published by Copernicus Publications on behalf of the European Geosciences Union. OA factors as OH aging increased. After OH oxidation in the OFR, the hygroscopicity of the OA increased with increasing elemental O : C up to O : C∼1.0, and then decreased as O : C increased further. Possible reasons for this decrease are discussed. The measured SOA formation was compared to the amount predicted from the concentrations of measured ambient SOA precursors and their SOA yields. While measured ambient precursors were sufficient to explain the amount of SOA formed from O 3 , they could only explain 10-50 % of the SOA formed from OH. This is consistent with previous OFR studies, which showed that typically unmeasured semivolatile and intermediate volatility gases (that tend to lack C=C bonds) are present in ambient air and can explain such additional SOA formation. To investigate the sources of the unmeasured SOA-forming gases during this campaign, multilinear regression analysis was performed between measured SOA formation and the concentration of gas-phase tracers representing different precursor sources. The majority of SOA-forming gases present during both seasons were of biogenic origin. Urban sources also contributed substantially in both seasons, while biomass burning sources were more important during the dry season. This study enables a better understanding of SOA formation in environments with diverse emission sources.

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Section: Estimating Source Contributions To Potential Soa Using Multimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Secondary organic aerosol formation from ambient air in an oxidation flow reactor in central Amazonia

Palm¹,

Sá²,

Day³

et al. 2018

Atmos. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

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“…Thus, the region is a valuable laboratory, for example for studying the impact of anthropogenic emissions of air pollutants on atmospheric chemical composition. Although there are a number of studies involving the measurements of atmospheric pollutants in the Amazon region (e.g., Kuhn et al, 2010;Trebs et al, 2012;Baars et al, 2012;Artaxo et al, 2013), most of the contribution was published very recently with the results of the GoAmazon2014/5 project Alves et al, 2016;Pöhlker et al, 2016;de Sá et al, 2017;Kourtchev et al, 2016;Hu et al, 2016;Bateman et al, 2017;Cecchini et al, 2016;Jardine et al, 2016). In terms of numerical studies, only a few studies focusing the role of the anthropogenic emission sources in urban areas are available Andreae et al, 2012;Beck et al, 2013;Bela et al, 2015).…”

Section: S a Abou Rafee Et Al: Contributions Of Mobile Stationarymentioning

confidence: 99%

Contributions of mobile, stationary and biogenic sources to air pollution in the Amazon rainforest: a numerical study with the WRF-Chem model

et al. 2017

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Abstract. This paper evaluates the contributions of the emissions from mobile, stationary and biogenic sources on air pollution in the Amazon rainforest by using the Weather Research and Forecasting with Chemistry (WRF-Chem) model. The analyzed air pollutants were CO, NO x , SO 2 , O 3 , PM 2.5 , PM 10 and volatile organic compounds (VOCs). Five scenarios were defined in order to evaluate the emissions by biogenic, mobile and stationary sources, as well as a future scenario to assess the potential air quality impact of doubled anthropogenic emissions. The stationary sources explain the highest concentrations for all air pollutants evaluated, except for CO, for which the mobile sources are predominant. The anthropogenic sources considered resulted an increasing in the spatial peak-temporal average concentrations of pollutants in 3 to 2780 times in relation to those with only biogenic sources. The future scenario showed an increase in the range of 3 to 62 % in average concentrations and 45 to 109 % in peak concentrations depending on the pollutant. In addition, the spatial distributions of the scenarios has shown that the air pollution plume from the city of Manaus is predominantly transported west and southwest, and it can reach hundreds of kilometers in length.

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“…These unique compounds all contained high DBE values (9 or greater for C 16 -C 25 molecules), suggesting the presence of multiple double bonds or ring structures. In the Amazon, Kourtchev et al (2016) previously found a similar subset of these unidentified CHOS compounds in SOA samples, suggesting a biogenic influence. Many organosulfates and nitrooxy-organosulfates, previously reported in laboratory studies, ambient aerosols, and cloud water as derived from monoterpene oxidation (Boone et al, 2015;Hamilton et al, 2013;Iinuma et al, 2007aIinuma et al, , b, 2009Kristensen et al, 2016;Kristensen and Glasius, 2011;Lin et al, 2012;Mazzoleni et al, 2012;Nguyen et al, 2012b;Nozière et al, 2010;O'Brien et al, 2014;Pratt et al, 2013;Stone et al, 2012;Surratt et al, 2008), were detected in the biogenic-influenced cloud water samples (Table 2), also consistent with monoterpene emissions along the air mass trajectories (Guenther et al, 2006).…”

Section: Biogenic Influencementioning

confidence: 99%

Biogenic, urban, and wildfire influences on the molecular composition of dissolved organic compounds in cloud water

Cook¹,

Lin²,

Peng³

et al. 2017

Atmos. Chem. Phys.

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Abstract. Organic aerosol formation and transformation occurs within aqueous aerosol and cloud droplets, yet little is known about the composition of high molecular weight organic compounds in cloud water. Cloud water samples collected at Whiteface Mountain, New York, during AugustSeptember 2014 were analyzed by ultra-high-resolution mass spectrometry to investigate the molecular composition of dissolved organic carbon, with a focus on sulfur-and nitrogen-containing compounds. Organic molecular composition was evaluated in the context of cloud water inorganic ion concentrations, pH, and total organic carbon concentrations to gain insights into the sources and aqueous-phase processes of the observed high molecular weight organic compounds. Cloud water acidity was positively correlated with the average oxygen : carbon ratio of the organic constituents, suggesting the possibility for aqueous acid-catalyzed (prior to cloud droplet activation or during/after cloud droplet evaporation) and/or radical (within cloud droplets) oxidation processes. Many tracer compounds recently identified in laboratory studies of bulk aqueous-phase reactions were identified in the cloud water. Organosulfate compounds, with both biogenic and anthropogenic volatile organic compound precursors, were detected for cloud water samples influenced by air masses that had traveled over forested and populated areas. Oxidation products of long-chain (C 10−12 ) alkane precursors were detected during urban influence. Influence of Canadian wildfires resulted in increased numbers of identified sulfur-containing compounds and oligomeric species, including those formed through aqueous-phase reactions involving methylglyoxal. Light-absorbing aqueous-phase products of syringol and guaiacol oxidation were observed in the wildfire-influenced samples, and dinitroaromatic compounds were observed in all cloud water samples (wildfire, biogenic, and urban-influenced). Overall, the cloud water molecular composition depended on air mass source influence and reflected aqueous-phase reactions involving biogenic, urban, and biomass burning precursors.

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Molecular composition of organic aerosols in central Amazonia: an ultra-high-resolution mass spectrometry study

Cited by 90 publications

References 87 publications

Secondary organic aerosol formation from ambient air in an oxidation flow reactor in central Amazonia

Secondary organic aerosol formation from ambient air in an oxidation flow reactor in central Amazonia

Contributions of mobile, stationary and biogenic sources to air pollution in the Amazon rainforest: a numerical study with the WRF-Chem model

Biogenic, urban, and wildfire influences on the molecular composition of dissolved organic compounds in cloud water

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