HR: 16:45h
AN: A54B-04    [Abstracts]
TI: The sensitivity of regional air pollution over the United States to future global climate and anthropogenic emissions changes: Part 1. Ozone
AU: * Racherla, P N
EM: pavanracherla@cmu.edu
AF: Dept. of Engineering and Public Policy, 5000 Forbes Avenue Carnegie Mellon University, Pittsburgh, PA 15213, United States
AU: Adams, P J
EM: petera@andrew.cmu.edu
AF: Dept. of Engineering and Public Policy, 5000 Forbes Avenue Carnegie Mellon University, Pittsburgh, PA 15213, United States
AU: Adams, P J
EM: petera@andrew.cmu.edu
AF: Dept. of Civil and Environmental Engineering, 5000 Forbes Avenue Carnegie Mellon University, Pittsburgh, PA 15213, United States
AB: We examined the relative importance of future changes in climate, anthropogenic emissions, biogenic VOC emissions, CH₄, and long-range air pollution transport on U.S. O₃ by performing a suite of simulations with an an integrated model of global climate, gas-phase chemistry and aerosols. Where applicable we used the A2 2050s climate as a representative future climate, and the A2 2050s (overall U.S. emissions increase) and B1 2050s (overall U.S. emissions decrease) emissions for future emissions. The model simulations show that U.S. O₃ is sensitive first and foremost to U.S. anthropogenic emissions changes, best illustrated in the domain- average changes in the average daily maximum 8-hour O₃ concentrations (MDA8-O₃) over the eastern U.S. (May-September) due to: 1) climate change with present-day anthropogenic emissions (2.1 ppbv); 2) anthropogenic emissions change alone (-9 to 9 ppbv); 3) climate change with different emissions regimes (0.9 to 3.4 ppbv); 4) increased global CH₄ concentration only (2.4 ppbv); and, 5) long-range air pollution transport (1.4 ppbv). The 95^th-percentile O₃ increase (May-September) due to climate change with B1 and A2 emissions is 1 ppbv and 10 ppbv, respectively. Therefore, the O₃ effect of climate change is minimized under an emissions reduction scenario and amplified under an emissions increase scenario. Increased CH₄ and long-range transport (A2) together contribute 3.8 ppbv to the domain-average MDA8-O₃ (May-September), thereby increasing the O₃ background over the U.S. With more stringent O₃ standards in the future, this increased O₃ background could significantly reduce the benefits of likely drastic U.S. emissions reductions over the next several decades.
DE: 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting