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Project Code [2007-INF-12-S5]
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Primary Funding Agency
Environmental Protection Agency
Co-Funding Organisation(s)
n/a
Lead Organisation
National University of Ireland Galway (NUIG)
Lead Applicant
Harald Berresheim
Project Abstract
A chemical ionisation mass spectrometer (CIMS) will be used for real-time continuous measurements of the hydroxyl radical (OH) and gaseous sulfuric acid (H2SO4) in marine air at Mace Head research station on the west coast of Ireland. These measurements will significantly strengthen the existing research programme focussing on the study of background air pollution by ozone and particulate matter and its relation to climate change. The equipment is a special research type CIMS instrument to be built by the National Centre for Atmospheric Research (NCAR) in Boulder, Colorado (USA). The PI has extensive experience in operating such a system. There are no commercial instruments available for monitoring OH and H2SO4 in the atmosphere. The CIMS instrument consists of three major parts: 1. inlet and calibration system, 2. chemical ionisation chamber, and 3. analysis section with quadrupole mass spectrometer. Chemical ionisation of H2SO4 is achieved by reaction with NO3- ions at atmospheric pressure forming HSO4- product ions which are mass-selected by a quadrupole and detected by an electron multiplier. OH is rapidly titrated by excess 34SO2 added to the inlet section, and the equivalent H234SO4 is measured similar to the natural H2SO4 (30 sec time resolution). Calibration is based on known OH levels produced from UV photolysis of atmospheric water vapour at 189 nm.
Grant Approved
€196,000.00
Research Hub
Climate Change
Research Theme
Greenhouse Gas Emissions, Sinks, and Management Systems
Initial Projected Completion Date
13/11/2008