Near-ground ozone source attributions and outflow in central eastern China during MTX2006 J. Li1,2, Z. Wang2, H. Akimoto1, K. Yamaji1, M. Takigawa1, P. Pochanart1, Y. Liu1, H. Tanimoto3, and Y. Kanaya1 1Frontier Research Center for Global Change, Japan Agency for Marine-Earth Science and Technology, Japan 2State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Nansen-Zhu International Research Center (NZC), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, People's Republic of China 3National Institute for Environmental Studies, Tsukuba, Japan
Abstract. A 3-D regional chemical transport model, the Nested Air Quality Prediction
Model System (NAQPMS), with an on-line tracer tagging module was used to
study the source of the near-ground (<1.5 km above ground level) ozone at
Mt. Tai (36.25° N, 117.10° E, 1534 m a.s.l.) in Central Eastern
China (CEC) during the Mount Tai eXperiment 2006 (MTX2006). The model
reproduced the temporal and spatial variations of near-ground ozone and
other pollutants, and it captured highly polluted and clean cases well. The
simulated near-ground ozone level over CEC was 60–85 ppbv (parts per
billion by volume), which was higher than values in Japan and over the North
Pacific (20–50 ppbv). The simulated tagged tracer data indicated that the
regional-scale transport of chemically produced ozone over other areas in
CEC contributed to the greatest fraction (49%) of the near-ground mean
ozone at Mt. Tai in June; in situ photochemistry contributed only 12%.
Due to high anthropogenic and biomass burning emissions that occurred in the
southern part of the CEC, the contribution to ground ozone levels from this
area played the most important role (32.4 ppbv, 37.9% of total ozone) in
the monthly mean ozone concentration at Mt. Tai; values reached 59 ppbv
(62%) on 6–7 June 2006. The monthly mean horizontal distribution of
chemically produced ozone from various ozone production regions indicated
that photochemical reactions controlled the spatial distribution of O3
over CEC. The regional-scale transport of pollutants also played an
important role in the spatial and temporal distribution of ozone over CEC.
Chemically produced ozone from the southern part of the study region can be
transported northeastwardly to the northern rim of CEC; the mean
contribution was 5–10 ppbv, and it reached 25 ppbv during high ozone
events. Studies of the outflow of CEC ozone and its precursors, as well as
their influences and contributions to the ozone level over adjacent
regions/countries, revealed that the contribution of CEC ozone to mean ozone
mixing ratios over the Korean Peninsula and Japan was 5–15 ppbv, of which
about half was due to the direct transport of ozone from CEC and half was
produced locally by ozone precursors transported from CEC.
Citation: Li, J., Wang, Z., Akimoto, H., Yamaji, K., Takigawa, M., Pochanart, P., Liu, Y., Tanimoto, H., and Kanaya, Y.: Near-ground ozone source attributions and outflow in central eastern China during MTX2006, Atmos. Chem. Phys., 8, 7335-7351, doi:10.5194/acp-8-7335-2008, 2008.