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Estimation of NH 4 + /SO 4 2- Molar Ratios Using URM Modeling Outputs - Part 2. Jim Boylan, Talat Odman, Ted Russell April 24, 2001. Outline. Molar Ratio Equation Model Results for July 11 - 19, 1995 SO 2 and NH 3 Emissions NH 4 + /SO 4 2- Molar Ratios SO 4 2- Concentration
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Estimation of NH4+/SO42- Molar Ratios Using URM Modeling Outputs - Part 2 Jim Boylan, Talat Odman, Ted Russell April 24, 2001 Georgia Institute of Technology
Outline • Molar Ratio Equation • Model Results for July 11 - 19, 1995 • SO2 and NH3 Emissions • NH4+/SO42- Molar Ratios • SO42- Concentration • Model Results for July 23 - 31, 1991 • SO2 and NH3 Emissions • NH4+/SO42- Molar Ratios • SO42- Concentration Georgia Institute of Technology
Molar Ratio Equation • If we assume or show that the moles of Na+ are small compared to the moles of NH4+, we can estimate the molar ratio of NH4+ to SO42-. • If the moles of Na+ and NH4+ are similar, we can assume that both are in the same sulfate form. Georgia Institute of Technology
SO2 Emissions on July 15, 1995 Georgia Institute of Technology
SO2 and NH3 Emissions on July 15, 1995 Georgia Institute of Technology
July 11, 1995 Georgia Institute of Technology
July 12, 1995 Georgia Institute of Technology
July 13, 1995 Georgia Institute of Technology
July 14, 1995 Georgia Institute of Technology
July 15, 1995 Georgia Institute of Technology
July 16, 1995 Georgia Institute of Technology
July 17, 1995 Georgia Institute of Technology
July 18, 1995 Georgia Institute of Technology
July 19, 1995 Georgia Institute of Technology
SO2 Emissions on July 27, 1991 Georgia Institute of Technology
SO2 and NH3 Emissions on July 27, 1991 Georgia Institute of Technology
July 23, 1991 Georgia Institute of Technology
July 24, 1991 Georgia Institute of Technology
July 25, 1991 Georgia Institute of Technology
July 26, 1991 Georgia Institute of Technology
July 27, 1991 Georgia Institute of Technology
July 28, 1991 Georgia Institute of Technology
July 29, 1991 Georgia Institute of Technology
July 30, 1991 Georgia Institute of Technology
July 31, 1991 Georgia Institute of Technology
Summary • The NH4+/SO42- molar ratios are dependent on the concentrations of aerosol sulfate and gas-phase ammonia, which vary spatially. • Areas with little or no ammonia emissions (e.g. WV) tend to have lower NH4+/SO42- molar ratios. • In general, the July 1991 episode shows lower NH4+/SO42- molar ratios than the July 1995 episode for the same sulfate concentrations. • July 1995: little H2SO4 when [SO42-] < 16 mg/m3 • July 1991: little H2SO4 when [SO42-] < 10 mg/m3 Georgia Institute of Technology