Abstract
To determine reasonable emission reduction measures for the mitigation of photochemical oxidant (ozone) pollutions over the Kanto area, it is important to know whether the sensitivity of the ozone concentration to precursor emissions is VOC-sensitive or NOx-sensitive at each location. Using a three-dimensional chemical transport model (CTM), we estimated the spatial distribution of the sensitivity regimes for the daily maximum ozone concentrations at each location over the Kanto area for a total of three days on which warning-level ozone was formed within the Kanto area. The Biogenic VOC (BVOC) emission amounts, input to the CTM, were estimated by considering recent emission measurements for Japanese native plant species. The results showed the sensitivity regime was VOC-sensitive over the limited regions near or within the urban center and was NOx-sensitive over most regions including the areas which had many warning-level ozone concentration days. On the other hand, the simulation results obtained using previous lower BVOC emission estimates showed that the regions with VOC-sensitive regimes significantly increased, indicating that the BVOC emission amounts input to the CTM significantly affects the estimated ozone concentration sensitivity regimes.
