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Institute for Chemical Process and Environmental Technology Helmut Roth, Weimin Jiang, Dazhong Yin, and Éric Giroux CMAQ Nucleation Algorithms and their impact on PM modeling results in the Lower Fraser Valley National Research Council of Canada Ottawa, Canada
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Institute for Chemical Process and Environmental Technology Introduction Nucleation Rates Impact on PM Conclusions & future work
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Institute for Chemical Process and Environmental Technology Introduction Episode: Pacific ’93 (1993 Jul 31 – Aug 07) Emissions: SMOKE, Giroux, É. et al Meteorology: MM5, Yin, D. et al Domain Nucleation Algorithms
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Institute for Chemical Process and Environmental Technology Horizontal domains
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Institute for Chemical Process and Environmental Technology Nucleation parameterizations & algorithms HK98: Harrington and Kreidenweis (1998) Fully coupled equations of 2-mode 2-moment model implemented in aero2 KLPx: Kulmala et al (1998) Equations of classical nucleation theory Implemented in aero2, aero3: KLP2, KLP3 Differences in number distribution, density s ulphuric acid – water system
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Institute for Chemical Process and Environmental Technology Nucleation rates: modeling
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Institute for Chemical Process and Environmental Technology 1 st layer domain-average number rates
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Institute for Chemical Process and Environmental Technology 1 st layer domain average ASO4I rates
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Institute for Chemical Process and Environmental Technology 1 st layer number rate statistics all maxima occur in cell (17,8) Neptune Beach
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Institute for Chemical Process and Environmental Technology Time-average, 1 st layer number rate
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Institute for Chemical Process and Environmental Technology Correlation at time of peak nucleation r 2 =0.9 Aug 05 13:00
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Institute for Chemical Process and Environmental Technology Impact on PM concentrations: model runs Common inputs Full gas phase calculations All aerosol processes Different nucleation algorithms: NOOP HK98 KLP2 KLP3
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Institute for Chemical Process and Environmental Technology Number concentration i-mode PM 2.5
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Institute for Chemical Process and Environmental Technology Time-average, 1 st layer NUMATKN
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Institute for Chemical Process and Environmental Technology Sulphate (ASO4) concentration PM 2.5 i-mode
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Institute for Chemical Process and Environmental Technology Time-average, 1 st layer ASO4I
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Institute for Chemical Process and Environmental Technology Main Conclusions KLP2 and KLP3 results very similar KLPx had greatest individual cell rate. HK98 had greatest average rates. HK98 more responsive to [SULAER] fluctuations. HK98 increases number concentration over NOOP; KLPx does not. No increase in PM 2.5 SO 4 mass over NOOP.
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Institute for Chemical Process and Environmental Technology Future work Impact of nucleation algorithms on model performance using ambient number concentration data
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Institute for Chemical Process and Environmental Technology Acknowledgements U.S. EPA: CMAQ source code Environment Canada: emissions and met data, ambient PM mass data Program of Energy Research and Development (PERD) in Canada: funding support
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Institute for Chemical Process and Environmental Technology Thank you !
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Institute for Chemical Process and Environmental Technology Time-average, 1 st layer mass rate
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