Date of Award

12-1997

Degree Name

Master of Arts

Department

Chemistry

First Advisor

Dr. Steven Bertman

Second Advisor

Dr. Susan Burns

Third Advisor

Dr. Michael Dziewatkoski

Access Setting

Masters Thesis-Open Access

Abstract

Simultaneous measurements of peroxymethacryloyl nitrate (MPAN) and its primary and secondary precursors, methacarolein (MACR) and isoprene, were carried out for the first time in July 1995 at a semi-rural site southeast of Nashville. In addition to these compounds, peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN), other volatile organic compounds (VOCs) and supporting measurements were also collected in collaboration with other research groups. The mean concentrations of PAN, PPN, MPAN and MACR were found to be 485 pptv, 50 pptv, 30 pptv and 0.290 ppbv respectively. MP AN levels, which closely tracked those of MACR during the day, peaked and dropped earlier than PAN, PPN and ozone levels. The morning peaks in MACR and MPAN appear to be due to a combination of active photochemical synthesis and downward mixing of both compounds as the nocturnal boundary layer breaks up. There are daytime periods when MPAN and MACR do not correlate well and this appears to be associated with a combination of high NO2, high NO2/NO, and limited OH production which may simultaneously decrease MACR production and increase MPAN lifetime. Unlike PAN, MPAN did not correlate well with 03, constituted less than 1% of NOy and appeared to have a shorter ambient lifetime. This indicates that MPAN may not be a significant reservoir and transporter of NOx at Youth Inc.. As a result, ozone production through MP AN decomposition may be limited locally which makes MP AN a useful indicator of local biogenic photochemistry.

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