scholarly journals Epoxide formation from heterogeneous oxidation of benzo[a]pyrene with gas-phase ozone and indoor air

2017 ◽  
Vol 19 (10) ◽  
pp. 1292-1299 ◽  
Author(s):  
Shouming Zhou ◽  
Leo W. Y. Yeung ◽  
Matthew W. Forbes ◽  
Scott Mabury ◽  
Jonathan P. D. Abbatt
Keyword(s):  
Gas Phase ◽  
Indoor Air ◽  
Heterogeneous Oxidation ◽  
Diol Epoxides ◽  
Epoxide Formation

This work demonstrates the production of mono- and diol-epoxides from heterogeneous oxidation of benzo[a]pyrene with gas-phase ozone.

How to Select Adsorption Material for Removing Gas Phase Indoor Air Pollutants: A New Parameter and Approach

2012 ◽  
Vol 22 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Qiujian Xu ◽  
Yinping Zhang ◽  
Jinhan Mo ◽  
Xinxiao Li
Keyword(s):  
Gas Phase ◽  
Indoor Air ◽  
Air Pollutants ◽  
Indoor Air Pollutants

scholarly journals Effect of oxidant concentration, exposure time, and seed particles on secondary organic aerosol chemical composition and yield

2015 ◽  
Vol 15 (6) ◽  
pp. 3063-3075 ◽  
Author(s):  
A. T. Lambe ◽  
P. S. Chhabra ◽  
T. B. Onasch ◽  
W. H. Brune ◽  
J. F. Hunter ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Gas Phase ◽  
Flow Reactor ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Short Exposure ◽  
Heterogeneous Oxidation ◽  
Seed Particles ◽  
Aerosol Mass ◽  
Environmental Chambers

Abstract. We performed a systematic intercomparison study of the chemistry and yields of secondary organic aerosol (SOA) generated from OH oxidation of a common set of gas-phase precursors in a Potential Aerosol Mass (PAM) continuous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH concentrations ranging from 2.0 × 108 to 2.2 × 1010 molec cm−3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH concentrations ranging from 2 × 106 to 2 × 107 molec cm−3 over exposure times of several hours. The OH concentration in the chamber experiments is close to that found in the atmosphere, but the integrated OH exposure in the flow reactor can simulate atmospheric exposure times of multiple days compared to chamber exposure times of only a day or so. In most cases, for a specific SOA type the most-oxidized chamber SOA and the least-oxidized flow reactor SOA have similar mass spectra, oxygen-to-carbon and hydrogen-to-carbon ratios, and carbon oxidation states at integrated OH exposures between approximately 1 × 1011 and 2 × 1011 molec cm−3 s, or about 1–2 days of equivalent atmospheric oxidation. This observation suggests that in the range of available OH exposure overlap for the flow reactor and chambers, SOA elemental composition as measured by an aerosol mass spectrometer is similar whether the precursor is exposed to low OH concentrations over long exposure times or high OH concentrations over short exposure times. This similarity in turn suggests that both in the flow reactor and in chambers, SOA chemical composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors rather than heterogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than measured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed particles are routinely used.

Heterogeneous oxidation of indoor surfaces by gas-phase hydroxyl radicals

Indoor Air ◽  
2018 ◽  
Vol 28 (5) ◽  
pp. 655-664 ◽  
Author(s):  
R. Alwarda ◽  
S. Zhou ◽  
J. P. D. Abbatt
Keyword(s):  
Gas Phase ◽  
Hydroxyl Radicals ◽  
Heterogeneous Oxidation

scholarly journals Formation of gas-phase carbonyls from heterogeneous oxidation of polyunsaturated fatty acids at the air–water interface and of the sea surface microlayer

2014 ◽  
Vol 14 (3) ◽  
pp. 1371-1384 ◽  
Author(s):  
S. Zhou ◽  
L. Gonzalez ◽  
A. Leithead ◽  
Z. Finewax ◽  
R. Thalman ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Polyunsaturated Fatty Acids ◽  
Gas Phase ◽  
Sea Surface ◽  
Optical Absorption Spectroscopy ◽  
Initial Reaction ◽  
Surface Microlayer ◽  
Secondary Products ◽  
Heterogeneous Oxidation ◽  
Sea Surface Microlayer

Abstract. Motivated by the potential for reactive heterogeneous chemistry occurring at the ocean surface, gas-phase products were observed when a reactive sea surface microlayer (SML) component, i.e. the polyunsaturated fatty acids (PUFA) linoleic acid (LA), was exposed to gas-phase ozone at the air–seawater interface. Similar oxidation experiments were conducted with SML samples collected from two different oceanic locations, in the eastern equatorial Pacific Ocean and from the west coast of Canada. Online proton-transfer-reaction mass spectrometry (PTR-MS) University of Colorado light-emitting diode cavity-enhanced differential optical absorption spectroscopy (LED-CE-DOAS) were used to detect oxygenated gas-phase products from the ozonolysis reactions. The LA studies indicate that oxidation of a PUFA monolayer on seawater gives rise to prompt and efficient formation of gas-phase aldehydes. The products are formed via the decomposition of primary ozonides which form upon the initial reaction of ozone with the carbon–carbon double bonds in the PUFA molecules. In addition, two highly reactive dicarbonyls, malondialdehyde (MDA) and glyoxal, were also generated, likely as secondary products. Specific yields relative to reactant loss were 78%, 29%, 4% and < 1% for n-hexanal, 3-nonenal, MDA and glyoxal, respectively, where the yields for MDA and glyoxal are likely lower limits. Heterogeneous oxidation of SML samples confirm for the first time that similar carbonyl products are formed via ozonolysis of environmental samples.

scholarly journals Comparison of secondary organic aerosol formed with an aerosol flow reactor and environmental reaction chambers: effect of oxidant concentration, exposure time and seed particles on chemical composition and yield

2014 ◽  
Vol 14 (22) ◽  
pp. 30575-30609 ◽  
Author(s):  
A. T. Lambe ◽  
P. S. Chhabra ◽  
T. B. Onasch ◽  
W. H. Brune ◽  
J. F. Hunter ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Gas Phase ◽  
Flow Reactor ◽  
Heterogeneous Oxidation ◽  
Flow Reactors ◽  
Seed Particles ◽  
Aerosol Mass ◽  
Reaction Chambers ◽  
Environmental Chambers ◽  
Intercomparison Study

Abstract. We performed a systematic intercomparison study of the chemistry and yields of SOA generated from OH oxidation of a common set of gas-phase precursors in a Potential Aerosol Mass (PAM) continuous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH concentrations ranging from 2.0×108 to 2.2&amp;times1010 molec cm−3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH concentrations ranging from 2×106 to 2×107 molec cm−3 over exposure times of several hours. The OH concentration in the chamber experiments is close to that found in the atmosphere, but the integrated OH exposure in the flow reactor can simulate atmospheric exposure times of multiple days compared to chamber exposure times of only a day or so. A linear correlation analysis of the mass spectra (m=0.91–0.92, r2=0.93–0.94) and carbon oxidation state (m=1.1, r2=0.58) of SOA produced in the flow reactor and environmental chambers for OH exposures of approximately 1011 molec cm−3 s suggests that the composition of SOA produced in the flow reactor and chambers is the same within experimental accuracy as measured with an aerosol mass spectrometer. This similarity in turn suggests that both in the flow reactor and in chambers, SOA chemical composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors, rather than heterogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than measured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed particles are routinely used.

Gas-phase O3 reaction of dimethyl phthalate and diethylphthalate: a kinetic and product study

2021 ◽  
Author(s):  
María Antiñolo ◽  
María Teresa Baeza ◽  
Elena Jiménez ◽  
José Albaladejo
Keyword(s):  
Gas Phase ◽  
Indoor Air ◽  
Chemical Species ◽  
Decay Rates ◽  
Phase Reaction ◽  
Dimethyl Phthalate ◽  
Living Organisms ◽  
Particle Sizer ◽  
The Impact ◽  
Tof Ms

&lt;p&gt;Phthalates are chemical species widely used as plasticisers that are known to be absorbed by living organisms and negatively affect their health. Phthalates have been detected mostly indoors. For example, they have been measured in the gas phase, as part of particulate matter and on different surfaces in the form of dust.&lt;sup&gt;1-4&lt;/sup&gt; Although their presence in this kind of environments is well known and widely documented, there are scarce studies on their behaviour when they are in contact with tropospheric oxidants such as ozone (O&lt;sub&gt;3&lt;/sub&gt;) or hydroxyl radicals.&lt;sup&gt;5-7&lt;/sup&gt;&lt;/p&gt;&lt;p&gt;The aim of this work is to measure, for the first time, the kinetics of the gas-phase reaction of O&lt;sub&gt;3&lt;/sub&gt; with two phthalates: dimethyl phthalate (DMP) and diethyl phthalate (DEP). In a smog chamber at room temperature and atmospheric pressure, decay rates of DMF or DEF are measured by a Proton Transfer-Time of Flight-Mass Spectrometer (PTR-ToF-MS), while the O&lt;sub&gt;3&lt;/sub&gt; concentration is determined by Fourier Transform Infrared (FTIR) spectroscopy. Gas-phase products are also monitored by PTR-ToF-MS and secondary organic aerosol (SOA) formation is also evaluated by a Fast Mobility Particle Sizer. The impact on the indoor air quality of DMP and DEP will be discussed considering their atmospheric lifetime and the generated products.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;REFERENCES: 1. &lt;/strong&gt;Bornehag, C.G.; Lundgren, B.; Weschler, C. J.; Sigsgaard, T.; Hagerhed-Engman, L.; Sundell, J. Environ. Health Perspect. &lt;strong&gt;2005,&lt;/strong&gt; 113, 1399-404; &lt;strong&gt;2. &lt;/strong&gt;Rudel, R. A.; Perovich, L. J. Atmos. Environ. &lt;strong&gt;2009&lt;/strong&gt;, 43, 170&amp;#8209;181; &lt;strong&gt;3. &lt;/strong&gt;Fromme, H.; Lahrz, T.; Piloty, M.; Gebhart, H.; Oddoy, A.; R&amp;#252;den, H. Indoor Air &lt;strong&gt;2004,&lt;/strong&gt; 14, 188-195; &lt;strong&gt;4. &lt;/strong&gt;Larsson, K.; Lindh, C. H.; J&amp;#246;nsson, B.A.; Giovanoulis, G.; Bibi, M.; Bottai, M.; Bergstr&amp;#246;m, A.; Berglung, M. Environ. Int. &lt;strong&gt;2017&lt;/strong&gt;, 102, 114-124; &lt;strong&gt;5. &lt;/strong&gt;Mansouri, L.; Mohammed, H.; Tizaoui, C.; Bousselmi, L. Desalination Water Treat. &lt;strong&gt;2013&lt;/strong&gt;, 51, 6698-6710; &lt;strong&gt;6. &lt;/strong&gt;Mohan, S.; Mamane, H.; Avisar, D.; Gozlan, I.; Kaplan, A.; Dayalan, G. Materials &lt;strong&gt;2019&lt;/strong&gt;, 12, 4119 (3); &lt;strong&gt;7. &lt;/strong&gt;Due&amp;#241;as Moreno, J.; Rodr&amp;#237;guez S, J.L.; Poznyak, T.; Chairez, I.; Dorantes-Rosales, H.J. J. Environ. Manage. &lt;strong&gt;2020&lt;/strong&gt;, 270, 110863 (7).&lt;/p&gt;

Evolution in the Reactivity of Citric Acid toward Heterogeneous Oxidation by Gas-Phase OH Radicals

2018 ◽  
Vol 2 (12) ◽  
pp. 1323-1329 ◽  
Author(s):  
Man Mei Chim ◽  
Christopher Y. Lim ◽  
Jesse H. Kroll ◽  
Man Nin Chan
Keyword(s):  
Citric Acid ◽  
Gas Phase ◽  
Oh Radicals ◽  
Heterogeneous Oxidation
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