Objective
To better understand the photooxidant formation by improving and harmonising the quality of atmospheric peroxy radical measurements.
The specific taks of the project are:
-to characterise and compare existing calibration methods for peroxy radicals
-to develop reliable calibration method for field studies -to determine the relative response of the chemical amplifier for HO2 and different organic RO2;
-to refine the chemistry in chemical amplifiers
-to develop a common model of chemical amplifiers based on the laboratory results
-to define the optimum operating conditions for chemical amplifiers with respect to HO2 and RO2
detection.
The project has three components: a formal laboratory intercomparison of RO2 measurements and calibration
sources under controlled conditions, laboratory experiments to determine the characteristic sensitivity of the
chemical amplifier (CA) for different organic peroxy radicals, and modelling studies to build a common
understanding of the relevant chemical and physical processes in the CA.
Since CA is an indirect method which is based on a relatively complex chemical mechanism, a number of
difficulties persist to reliably assess the quality of such measurements. A first intercomparison that was made
at Schauinsland in Summer 1994 as part of the EC project OCTA showed general agreement (within a factor
of 2) between the different CAs and different instruments for atmospheric measurements but revealed a number
of difficulties that could not be clarified during the field campaign. These included the comparison of the
different calibration techniques. The results also suggested that the CAs systematically underestimate the
concentrations of organic RO2 radicals.
The laboratory intercomparison will be conducted at KFA J|lich and will last about 4 weeks.
Topic(s)
Call for proposal
Data not availableFunding Scheme
CSC - Cost-sharing contractsCoordinator
52425 Jülich
Germany