HR: 1340h
AN: A43C-0073    [Abstracts]
TI: Measurements of Peroxy Radicals in the UK Summer Heatwave of 2003
AU: * Jacob, M J
EM: mjj3@le.ac.uk
AF: Department of chemistry, University of Leicester, University Road, Leicester, LE1 7RH United Kingdom
AU: Monks, P S
EM: psm7@le.ac.uk
AF: Department of chemistry, University of Leicester, University Road, Leicester, LE1 7RH United Kingdom
AU: Lewis, A C
EM: acl5@york.ac.uk
AF: Department of Chemistry, University of York, Heslington, York, YO10 5DD United Kingdom
AU: Hamilton, J F
EM: jfh2@york.ac.uk
AF: Department of Chemistry, University of York, Heslington, York, YO10 5DD United Kingdom
AU: Hopkins, J H
EM: jh61@york.ac.uk
AF: Department of Chemistry, University of York, Heslington, York, YO10 5DD United Kingdom
AU: Bandy, B J
EM: B.Bandy@uea.ac.uk
AF: School of Environmental Sciences, University of East Anglia, University Plain, Norwich, NR4 7TJ United Kingdom
AU: Penkett, S A
EM: M.Penkett@uea.ac.uk
AF: School of Environmental Sciences, University of East Anglia, University Plain, Norwich, NR4 7TJ United Kingdom
AB: The sum of organic peroxy radicals and HO$_2$ was measured with a peroxy radical chemical amplifier (PERCA) during the Tropospheric ORganic CHemistry experiment (TORCH) in August 2003 on a ground based platform at a site in the South of England. Measurements of peroxy radicals, which act as intermediates and chain carriers in the gas phase radical chain oxidation of volatile organic compounds, can be used to determine the in-situ production rate of ozone. Record temperatures (up to 39 degrees Celsius or 100 degrees Fahrenheit) were experienced in the UK during the second week of August and this work focuses on the significance of peroxy radical levels to ozone production during this period. Maximum total peroxy radical mixing ratios over the week of the heatwave were up to five times the levels recorded in the periods before and after the hot weather while ozone mixing ratios reached 152ppb - well above the European safety threshold of 90ppb. A range of VOCs was also measured and data from fifteen alkenes, including the biogenic compound isoprene, were used to calculate peroxy radical production rates. On the day of the highest maximum temperature isoprene was found to have the greatest contribution towards peroxy radical production via alkene ozonolysis over a significant part of the day. The extent to which the ozonolysis of alkenes was important in the production of peroxy radicals and implications for ozone production will be discussed.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting