W. T. Hutzell 1 , G. Pouliot 2 , and D. J. Luecken 1 1 Atmospheric Modeling Division, U. S. Environmental Protection Agency 2 Atmospheric Sciences Modeling Division, Air Resources Laboratory, National Oceanic and Atmospheric October 16, 2006 Changes to the Chemical Mechanisms for Hazardous Air Pollutants in CMAQ version 4.6
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Changes to the Chemical Mechanisms for Hazardous Air Pollutants in CMAQ version 4.6
W. T. Hutzell 1 , G. Pouliot 2 , and D. J. Luecken 1 1 Atmospheric Modeling Division, U. S. Environmental Protection Agency 2 Atmospheric Sciences Modeling Division, Air Resources Laboratory, National Oceanic and Atmospheric October 16, 2006. - PowerPoint PPT Presentation
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W. T. Hutzell1, G. Pouliot2, and D. J. Luecken1
1Atmospheric Modeling Division,U. S. Environmental Protection Agency
2Atmospheric Sciences Modeling Division, Air Resources Laboratory, National Oceanic and Atmospheric
October 16, 2006
Changes to the Chemical Mechanisms for Hazardous Air Pollutants in CMAQ version 4.6
Background• CMAQ version 4.5 has two different mechanisms
for Hazardous Air Pollutants (HAPs). CB4TX1P SAPRC99TX2P
• Each includes a specific type of HAPs. identified to produce large health risks over urban
areas treated because they can be simulated as gas phase
compounds.
• Each omits toxic components in Particulate Matter (PM) Also linked to large risks to health over urban areas.
Background (cont.)• Version 4.6 introduces two new mechanisms for
several HAPs. • Each includes HAPs in CMAQ version 4.5. • They also include more gas phase HAPs, • As well as aerosol phase HAPs that represent
several toxic metals and diesel emissions. • One mechanism, called SAPRC99TX3, builds
upon SAPRC99TX2P. • The other, called CB05CLTX, adapts the
What does CL in CB05CLTX mean?• CB05CLTX contains additional species and reactions
not in SAPRC99TX3. Six species track emissions from anthropogenic and
biogenic sources (see version 4.6 release notes). Other species simulate the fate and transport of Cl2 and
HCl.
• Additional reactions represent how chlorine compounds affect ozone. Reactions are based on Yarwood et al. (2005). We added the reaction, “HCl + OH Cl.”
• NOTE, current mechanism settings omit Cl2 and HCl emissions.
Closing Points
• New HAP mechanisms have not been evaluated against observations.
• Each gives results consistent to the mechanisms from that they were derived, i.e., CB05 or SAPRC99.
• The new mechanisms then allow simultaneously studying criteria and numerous toxic pollutants.
Disclaimer: The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number
DW13921548. This work constitutes a contribution to the NOAA Air Quality Program. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.