ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Environment Pollution  (6)
  • ASTROPHYSICS  (3)
  • Thorium dating  (2)
  • electric utility  (2)
  • nitrogen oxides  (2)
Collection
Keywords
Publisher
Years
  • 11
    facet.materialart.
    Unknown
    Investigation of a Potential HCHO Measurement Artifact from ISOPOOH (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Recent laboratory experiments have shown that a first generation isoprene oxidation product, ISOPOOH, can decompose to methyl vinyl ketone (MVK) and methacrolein (MACR) on instrument surfaces, leading to overestimates of MVK and MACR concentrations. Formaldehyde (HCHO) was suggested as a decomposition co-product, raising concern that in situ HCHO measurements may also be affected by an ISOPOOH interference. The HCHO measurement artifact from ISOPOOH for the NASA In Situ Airborne Formaldehyde instrument (ISAF) was investigated for the two major ISOPOOH isomers, (1,2)-ISOPOOH and (4,3)-ISOPOOH, under dry and humid conditions. The dry conversion of ISOPOOH to HCHO was 3+/-2% and 6+/-4% for (1,2)-ISOPOOH and (4,3)-ISOPOOH, respectively. Under humid (RH= 40-60%) conditions, conversion to HCHO was 6+/-4% for (1,2)-ISOPOOH and 10+/-5% for (4,3)-ISOPOOH. The measurement artifact caused by conversion of ISOPOOH to HCHO in the ISAF instrument was estimated for data obtained on the 2013 September 6 flight of the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign. Prompt ISOPOOH conversion to HCHO was the source for 〈4% of the observed HCHO, including in the high-isoprene boundary layer. Time-delayed conversion, where previous exposure to ISOPOOH affects measured HCHO later in flight, was conservatively estimated to be 〈 10% of observed HCHO and is significant only when high ISOPOOH sampling periods immediately precede periods of low HCHO.
    Keywords: Environment Pollution
    Type: GSFC-E-DAA-TN41602 , Atmospheric Measurement Techniques (ISSN 1867-1381) (e-ISSN 1867-8548); 9; 9; 4561-4568
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 12
    facet.materialart.
    Unknown
    Observational Constraints on Glyoxal Production from Isoprene Oxidation and Its Contribution to Organic Aerosol over the Southeast United States (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: We use a 0-D photochemical box model and a 3-D global chemistry-climate model, combined with observations from the NOAA Southeast Nexus (SENEX) aircraft campaign, to understand the sources and sinks of glyoxal over the Southeast United States. Box model simulations suggest a large difference in glyoxal production among three isoprene oxidation mechanisms (AM3ST, AM3B, and Master Chemical Mechanism (MCM) v3.3.1). These mechanisms are then implemented into a 3-D global chemistry-climate model. Comparison with field observations shows that the average vertical profile of glyoxal is best reproduced by AM3ST with an effective reactive uptake coefficient gamma(sub glyx) of 2 x 10(exp -3) and AM3B without heterogeneous loss of glyoxal. The two mechanisms lead to 0-0.8micrograms m(exp -3) secondary organic aerosol (SOA) from glyoxal in the boundary layer of the Southeast U.S. in summer. We consider this to be the lower limit for the contribution of glyoxal to SOA, as other sources of glyoxal other than isoprene are not included in our model. In addition, we find that AM3B shows better agreement on both formaldehyde and the correlation between glyoxal and formaldehyde (RGF[GLYX]/[HCHO]), resulting from the suppression of delta-isoprene peroxy radicals (delta-ISOPO2). We also find that MCM v3.3.1 may underestimate glyoxal production from isoprene oxidation, in part due to an underestimated yield from the reaction of isoprene epoxydiol (IEPOX) peroxy radicals with HO2. Our work highlights that the gas-phase production of glyoxal represents a large uncertainty in quantifying its contribution to SOA.
    Keywords: Environment Pollution
    Type: GSFC-E-DAA-TN41635 , Journal of Geophysical Research: Atmospheres (ISSN 2169-897X) (e-ISSN 2169-8996); 121; 16; 9849-9861
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 13
    facet.materialart.
    Unknown
    Emissions of Glyoxal and Other Carbonyl Compounds from Agricultural Biomass Burning Plumes Sampled by Aircraft (2017)
    In:  CASI
    Details
    Publication Date: 2019-08-09
    Description: We report enhancements of glyoxal relative to carbon monoxide and formaldehyde from biomass burning plumes intercepted from the NOAA WP-3D aircraft during the 2013 Southeast Nexus and 2015 Shale Oil and Natural Gas Nexus field campaigns. The intercepted biomass burning plumes were from small agricultural fires. Since the plume ages were not known, these values are normalized excess mixing ratios, instead of the more common emission ratio, which is used only for fresh emissions. Glyoxal was measured using broadband cavity enhanced spectroscopy, which provides a sensitive and highly selective measurement of glyoxal. Emissions of other species such as methane, formaldehyde, and nitrous acid agreed with previous laboratory and field measurements, but the glyoxal emissions relative to CO were on average a factor of 4 lower than previously reported. Several glyoxal loss processes such as aerosol uptake were examined to determine if they could affect the observed glyoxal concentrations, but they were insufficient to explain the lower measured values of glyoxal relative to other biomass burning trace gases, indicating that glyoxal emissions from biomass burning may be significantly overestimated.
    Keywords: Environment Pollution
    Type: NF1676L-27262 , GSFC-E-DAA-TN47723 , Environmental Science and Technology (ISSN 0013-936X) (e-ISSN 1520-5851); 51; 20; 11761-11770
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...