In 2009, the Pollutant Standards Index (PSI) value exceeds 100 is 9 station-days. There are 5 station-days for PM10 and 4 station-days for O3. The percentage of days with PSI>100 were 1.23% which the lowest over the years. That means the result of air pollutants control strategy is good. There have several large-scale development plans to start at Changhua in the future. It is necessary to work out control strategies to keep air quality. The First step requires the development unit have to do the best for their promise of protect measures in EIA. The second step evolves different control strategies to construct period and operation period. Besides, we draw up Short-term, Mid-term, Long-term control strategies for stationary sources and mobile sources in order to reach the air quality goals of EPA already. The major air pollutant of Taiwan is Ozone (O3). The Changhua is the only country that secondary level prevention area of Ozone in Central Air Quality Area. However, the total emission of ozone precursor matter will be increase in Central area and Changhua in the years to come. It is possible to drop the Changhua ozone quality. For the reason, this project takes the grid model (CMAQ) to estimate the impact of important sources. The results of CMAQ modeling also provide the ideas to lay down ozone control strategy.

PSI、Control Strategy、Grid Model