Record:   Prev Next
作者 Cleary, Patricia Anne
書名 Precursors and co-products of catalytic ozone production: Nitrogen dioxide, alkyl nitrates and peroxy nitrates
國際標準書號 0496687948
book jacket
說明 120 p
附註 Source: Dissertation Abstracts International, Volume: 65-02, Section: B, page: 0756
Chair: Ronald C. Cohen
Thesis (Ph.D.)--University of California, Berkeley, 2003
In this thesis I describe methods for providing novel constraints on air quality models through tropospheric measurements of reactive nitrogen species and analyses of these measurements along with concurrent measurements of volatile organic compounds (VOC), O3 and meteorological parameters. The lack of routine observations of atmospheric NO2 is one of the major reasons that models have been evaluated primarily based on their predictions of ozone and not on their predictions of the major ozone precursors, NO x (NOx = NO + NO2) and VOC. A relatively inexpensive, specific, NO2 sensor using Laser Induced Fluorescence (LIF) has been designed, constructed and field-tested. The instrument combines a commercial, cw external cavity tunable diode laser (640 nm) and a continuous supersonic expansion to measure NO2 with a sensitivity of 145 pptv min -1 (S/N = 2). It is capable of autonomous operation for routine measurements of NO2
The partitioning of nitrogen oxides among reservoir species including peroxy nitrates (PNs), alkyl nitrates (ANs) and nitric acid affects the rate and location of ozone and fine particle production as well as of acid deposition in the troposphere. Only recently has it become possible to measure total alkyl nitrates (SigmaANs) and total peroxy nitrates (SigmaPNs). I describe detailed analyses of the quantities of SigmaANs, and SigmaPNs. The observations of SigmaANs correlate strongly with ozone and this correlation is used to derive an average branching ratio of the RO2 + NO reaction to alkyl nitrates of at least ∼4% in the air mass studied. The relationship between isoprene oxidation products and O3 at this same site is used to quantify the total ozone production and specify the known and unknown contributions. The isoprene contribution to ozone production is determined to be ∼14% and 26% of ozone production is attributed to unknown VOC
Measurements of SigmaPNs and aldehydes are used to derive the partitioning of SigmaPNs among individual PNs and to estimate OH in the Sacramento urban plume. Peroxy nitrates from C5--C9 aldehydes were predicted to constitute 32% of SigmaPNs although they have not been observed previously. OH is estimated to be 1.3 x 107 (+/-40%) molecules/cm3 at noon, and shows a strong diurnal cycle, with a maximum of 1.9 x 10 7 molecules/cm3 at 2 pm
School code: 0028
DDC
Host Item Dissertation Abstracts International 65-02B
主題 Chemistry, Physical
Environmental Sciences
Engineering, Environmental
0494
0768
0775
Alt Author University of California, Berkeley
Record:   Prev Next