TY - JOUR
T1 - Observations of total peroxy nitrates and aldehydes
T2 - Measurement interpretation and inference of OH radical concentrations
AU - Cleary, P. A.
AU - Wooldridge, P. J.
AU - Millet, D. B.
AU - McKay, M.
AU - Goldstein, A. H.
AU - Cohen, R. C.
PY - 2007
Y1 - 2007
N2 - We describe measurements of total peroxy nitrates (EPNs), NO2, O3 and several aldehydes at Granite Bay, California, during the Chemistry and Transport of the Sacramento Urban Plume-2001 (CATSUP 2001) campaign, from 19 July-16 September 2001. We observed a strong photochemically driven variation of EPNs during the day with the median of 1.2 ppb at noon. Acetaldehyde, pentanal, hexanal and methacrolein had median abundances in the daytime of 1.2ppb, 0.093 ppb, 0.14ppb, and 0.27 ppb, respectively. We compare steady state and time dependent calculations of the dependence of SPNs on aldehydes, OH, NO and NO2 showing that the steady state calculations are accurate to ±30% between 10:00 and 18:00 h. We use the steady state calculation to investigate the composition of SPNs and the concentration of OH at Granite Bay. We find that PN molecules that have never been observed before make up an unreasonably large fraction of the σPNs unless we assume that there exists a PAN source that is much larger than the acetaldehyde source. We calculate that OH at the site varied between 2 and 7 × 106 molecule cm-3 at noon during the 8 weeks of the experiment.
AB - We describe measurements of total peroxy nitrates (EPNs), NO2, O3 and several aldehydes at Granite Bay, California, during the Chemistry and Transport of the Sacramento Urban Plume-2001 (CATSUP 2001) campaign, from 19 July-16 September 2001. We observed a strong photochemically driven variation of EPNs during the day with the median of 1.2 ppb at noon. Acetaldehyde, pentanal, hexanal and methacrolein had median abundances in the daytime of 1.2ppb, 0.093 ppb, 0.14ppb, and 0.27 ppb, respectively. We compare steady state and time dependent calculations of the dependence of SPNs on aldehydes, OH, NO and NO2 showing that the steady state calculations are accurate to ±30% between 10:00 and 18:00 h. We use the steady state calculation to investigate the composition of SPNs and the concentration of OH at Granite Bay. We find that PN molecules that have never been observed before make up an unreasonably large fraction of the σPNs unless we assume that there exists a PAN source that is much larger than the acetaldehyde source. We calculate that OH at the site varied between 2 and 7 × 106 molecule cm-3 at noon during the 8 weeks of the experiment.
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U2 - 10.5194/acp-7-1947-2007
DO - 10.5194/acp-7-1947-2007
M3 - Article
AN - SCOPUS:34247385974
SN - 1680-7316
VL - 7
SP - 1947
EP - 1960
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
IS - 8
ER -