scholarly journals Chemical speciation of organic aerosol during the International Consortium for Atmospheric Research on Transport and Transformation 2004: Results from in situ measurements

2007 ◽  
Vol 112 (D10) ◽  
Author(s):  
Brent J. Williams ◽  
Allen H. Goldstein ◽  
Dylan B. Millet ◽  
Rupert Holzinger ◽  
Nathan M. Kreisberg ◽  
...  
Keyword(s):  
Chemical Speciation ◽  
Organic Aerosol ◽  
In Situ Measurements ◽  
Transport And Transformation ◽  
International Consortium ◽  
Atmospheric Research

scholarly journals Observations of glyoxal and formaldehyde as metrics for the anthropogenic impact on rural photochemistry

2012 ◽  
Vol 12 (2) ◽  
pp. 6049-6084 ◽  
Author(s):  
J. P. DiGangi ◽  
S. B. Henry ◽  
A. Kammrath ◽  
E. S. Boyle ◽  
L. Kaser ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Pinus Ponderosa ◽  
Model Comparison ◽  
Organic Aerosol ◽  
In Situ Measurements ◽  
Rapid Changes ◽  
Volatile Organic ◽  
Satellite Retrievals ◽  
Voc Mixtures

Abstract. We present simultaneous fast, in-situ measurements of formaldehyde and glyoxal from two rural campaigns, BEARPEX 2009 and BEACHON-ROCS, both located in Pinus Ponderosa forests with emissions dominated by biogenic volatile organic compounds (VOCs). Despite considerable variability in the formaldehyde and glyoxal concentrations, the ratio of glyoxal to formaldehyde, RGF, displayed a very regular diurnal cycle over nearly 2 weeks of measurements. The only deviations in RGF were toward higher values and were the result of a biomass burning event during BEARPEX 2009 and very fresh anthropogenic influence during BEACHON-ROCS. Other rapid changes in glyoxal and formaldehyde concentrations have hardly any affect on RGF and could reflect transitions between low and high NO regimes. The trend of increased RGF from both anthropogenic reactive VOC mixtures and biomass burning compared to biogenic reactive VOC mixtures is robust due to the short timescales over which the observed changes in RGF occurred. Satellite retrievals, which suggest higher RGF for biogenic areas, are in contrast to our observed trends. It remains important to address this discrepancy, especially in view of the importance of satellite retrievals and in-situ measurements for model comparison. In addition, we propose that RGF, together with the absolute concentrations of glyoxal and formaldehyde, represents a useful metric for biogenic or anthropogenic reactive VOC mixtures. In particular, RGF yields information about not simply the VOCs in an airmass, but the VOC processing that directly couples ozone and secondary organic aerosol production.

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