Near-ground ozone source attributions and outflow in central eastern China during MTX2006

Abstract

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 regionalscale 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 O 3 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 Correspondence to: J. Li (lijie8074@jamstec.go.jp) 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.

Gravity-Current-Driven Transport of Haze from the North China Plain to Northeast China in Winter 2010-Part 2: Model Simulation with Tagged Tracers

“…Compared with the sensitive analysis method employing intermittent emission, the online tagged method is an alternative and more efficient approach to evaluating the importance of various tagged regions. Similar analyses have been employed in previous studies (Davis et al 2003;Kondo et al 2004;Sudo and Akimoto 2007;Li et al 2008). The study by Wu et al (2011) provides more details on the tagged method.…”

“…The air pollutant tagged module was developed and coupled to the NAQPMS model (Li et al 2008). The model has been used to study issues related to transport of air pollutants and related chemical processes, the interaction between mineral aerosols and acid rain over east Asia on a regional scale (Huang et al 1995;Wang et al 2002;Li et al 2007), and the impact of mobile sources on air quality in Beijing on an urban scale (Wu et al 2010).…”

Overview of the Mount Tai Experiment (MTX2006) in central East China in June 2006: studies of significant regional air pollution

“…Source attributions from the regional scale down to sub-province levels were therefore made. In general, regional photochemical production of O 3 within CEC was the most important mechanism, showing a contribution of 51.4 ppbv (60.2 %) to a monthly mean O 3 mixing ratio (on a 24 h basis) of 85.4 ppbv (Li et al, 2008a). Specifically, the largest fractions of O 3 were formed in SSD, AH, and JS (32.4 ppbv or 37.9 %), influenced by high emission rates (including those from biomass burning) and favorable meteorological conditions in these areas.…”

“…The NAQPMS was used for studying source attribution and outflow of O 3 at Mt. Tai (Li et al, 2008a). The CMAQ was used to evaluate the impact of crop residue burning on O 3 , CO, BC, and OC over CEC (Yamaji et al, 2010), and to study the impact of the Asian monsoon on O 3 and precipitation acidity in eastern and central China (He et al, 2008;Ge et al, 2011).…”

“…Tai during the MTX2006 period (Li et al, 2008a). During this time period, CEC was covered with air masses with high O 3 concentrations (65-85 ppbv) in the model simulation.…”