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Hoffmann, Thorsten; Odum, Jay R.; Bowman, Frank M.; Collins, D. R.; Klockow, D.; Flagan, Richard C.; Seinfeld, John H.

doi:10.1023/a:1005734301837

Cited by 765 publications

(329 citation statements)

References 51 publications

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“…The selected biogenic precursors include isoprene, the most abundant non-methane hydrocarbon (Guenther et al, 2006); α-pinene, a well-studied monoterpene with emissions on the order of global anthropogenic emissions (Guenther et al, 1993;Piccot et al, 1992); and β-caryophyllene, a representative sesquiterpene. Both monoterpenes and sesquiterpenes have been shown to contribute significantly to ambient aerosol (Eddingsaas et al, 2012;Hoffmann et al, 1997;Tasoglou and Pandis, 2015;Goldstein and Galbally, 2007). Similarly, the anthropogenic precursors include pentadecane, a long-chain alkane; m-xylene, a singlering aromatic; and naphthalene, a polyaromatic.…”

Section: W Y Tuet Et Al: Inflammatory Responses To Soa Generated Fmentioning

confidence: 99%

Inflammatory responses to secondary organic aerosols (SOA) generated from biogenic and anthropogenic precursors

et al. 2017

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Abstract. Cardiopulmonary health implications resulting from exposure to secondary organic aerosols (SOA), which comprise a significant fraction of ambient particulate matter (PM), have received increasing interest in recent years. In this study, alveolar macrophages were exposed to SOA generated from the photooxidation of biogenic and anthropogenic precursors (isoprene, α-pinene, β-caryophyllene, pentadecane, m-xylene, and naphthalene) under different formation conditions (RO 2 + HO 2 vs. RO 2 + NO dominant, dry vs. humid). Various cellular responses were measured, including reactive oxygen and nitrogen species (ROS/RNS) production and secreted levels of cytokines, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). SOA precursor identity and formation condition affected all measured responses in a hydrocarbon-specific manner. With the exception of naphthalene SOA, cellular responses followed a trend where TNF-α levels reached a plateau with increasing IL-6 levels. ROS/RNS levels were consistent with relative levels of TNF-α and IL-6, due to their respective inflammatory and anti-inflammatory effects. Exposure to naphthalene SOA, whose aromatic-ring-containing products may trigger different cellular pathways, induced higher levels of TNF-α and ROS/RNS than suggested by the trend. Distinct cellular response patterns were identified for hydrocarbons whose photooxidation products shared similar chemical functionalities and structures, which suggests that the chemical structure (carbon chain length and functionalities) of photooxidation products may be important for determining cellular effects. A positive nonlinear correlation was also detected between ROS/RNS levels and previously measured DTT (dithiothreitol) activities for SOA samples. In the context of ambient samples collected during summer and winter in the greater Atlanta area, all laboratory-generated SOA produced similar or higher levels of ROS/RNS and DTT activities. These results suggest that the health effects of SOA are important considerations for understanding the health implications of ambient aerosols.

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Section: W Y Tuet Et Al: Inflammatory Responses To Soa Generated Fmentioning

confidence: 99%

Inflammatory responses to secondary organic aerosols (SOA) generated from biogenic and anthropogenic precursors

et al. 2017

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“…myrcene) tend to form less aerosol mass from ozonolysis than monoterpenes with exocyclic double bonds (e.g. β-pinene, sabinene; Hatakeyama et al, 1989;Hoffmann et al, 1997). Following the equation established by Bonn et al (2014, Eq.…”

Section: Reactivitymentioning

confidence: 99%

Monoterpene chemical speciation in a tropical rainforest:variation with season, height, and time of dayat the Amazon Tall Tower Observatory (ATTO)

et al. 2018

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Abstract. Speciated monoterpene measurements in rainforest air are scarce, but they are essential for understanding the contribution of these compounds to the overall reactivity of volatile organic compound (VOC) emissions towards the main atmospheric oxidants, such as hydroxyl radicals (OH), ozone (O 3 ) and nitrate radicals (NO 3 ). In this study, we present the chemical speciation of gas-phase monoterpenes measured in the tropical rainforest at the Amazon Tall Tower Observatory (ATTO, Amazonas, Brazil). Samples of VOCs were collected by two automated sampling systems positioned on a tower at 12 and 24 m height and analysed using gas chromatography-flame ionization detection. The samples were collected in October 2015, representing the dry season, and compared with previous wet and dry season studies at the site. In addition, vertical profile measurements (at 12 and 24 m) of total monoterpene mixing ratios were made using proton-transfer-reaction mass spectrometry. The results showed a distinctly different chemical speciation between day and night. For instance, α-pinene was more abundant during the day, whereas limonene was more abundant at night. Reactivity calculations showed that higher abundance does not generally imply higher reactivity. Furthermore, inter-and intra-annual results demonstrate similar chemodiversity during the dry seasons analysed. Simulations with a canopy exchange modelling system show simulated monoterpene mixing ratios that compare relatively well with the observed mixing ratios but also indicate the necessity of more experiments to enhance our understanding of in-canopy sinks of these compounds.

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“…VOC oxidation is closely related to radical production and consumption (Levy II, 1971), O 3 production, and the formation of secondary aerosols (Odum et al, 1996;Hoffmann et al, 1997;Volkamer et al, 2006;Hallquist et al, 2009), which have impacts on air quality and climate (Lippmann, 1991;Nel, 2005;Stocker et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Modeling of the chemistry in oxidation flow reactors with high initial NO

Peng

Jimenez

2017

Atmos. Chem. Phys.

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Abstract. Oxidation flow reactors (OFRs) are increasingly employed in atmospheric chemistry research because of their high efficiency of OH radical production from low-pressure Hg lamp emissions at both 185 and 254 nm (OFR185) or 254 nm only (OFR254). OFRs have been thought to be limited to studying low-NO chemistry (in which peroxy radicals (RO 2 ) react preferentially with HO 2 ) because NO is very rapidly oxidized by the high concentrations of O 3 , HO 2 , and OH in OFRs. However, many groups are performing experiments by aging combustion exhaust with high NO levels or adding NO in the hopes of simulating high-NO chemistry (in which RO 2 + NO dominates). This work systematically explores the chemistry in OFRs with high initial NO. Using box modeling, we investigate the interconversion of Ncontaining species and the uncertainties due to kinetic parameters. Simple initial injection of NO in OFR185 can result in more RO 2 reacted with NO than with HO 2 and minor non-tropospheric photolysis, but only under a very narrow set of conditions (high water mixing ratio, low UV intensity, low external OH reactivity (OHR ext ), and initial NO concentration (NO in ) of tens to hundreds of ppb) that account for a very small fraction of the input parameter space. These conditions are generally far away from experimental conditions of published OFR studies with high initial NO. In particular, studies of aerosol formation from vehicle emissions in OFRs often used OHR ext and NO in several orders of magnitude higher. Due to extremely high OHR ext and NO in , some studies may have resulted in substantial non-tropospheric photolysis, strong delay to RO 2 chemistry due to peroxynitrate formation, VOC reactions with NO 3 dominating over those with OH, and faster reactions of OH-aromatic adducts with NO 2 than those with O 2 , all of which are irrelevant to ambient VOC photooxidation chemistry. Some of the negative effects are the worst for alkene and aromatic precursors. To avoid undesired chemistry, vehicle emissions generally need to be diluted by a factor of > 100 before being injected into an OFR. However, sufficiently diluted vehicle emissions generally do not lead to high-NO chemistry in OFRs but are rather dominated by the low-NO RO 2 + HO 2 pathway. To ensure high-NO conditions without substantial atmospherically irrelevant chemistry in a more controlled fashion, new techniques are needed.

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Untitled

Cited by 765 publications

References 51 publications

Inflammatory responses to secondary organic aerosols (SOA) generated from biogenic and anthropogenic precursors

Inflammatory responses to secondary organic aerosols (SOA) generated from biogenic and anthropogenic precursors

Monoterpene chemical speciation in a tropical rainforest:variation with season, height, and time of dayat the Amazon Tall Tower Observatory (ATTO)

Modeling of the chemistry in oxidation flow reactors with high initial NO

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