Analysis of the concentration of water-soluble ions in fine suspended particulates from 105 to 108 years showed that the concentration of PM2.5 in Taiwan has decreased, so the concentration of major ions has also decreased. The analysis of the daily reverse trajectory of ozone events shows that the reason for the excessive O3_8hr in the western half of Taiwan is transmission within an hour, and the ozone sensitivity is controlled at the same time as the two pollutants of VOCs and NOx. However,match simulation to get priority control NOx.The combination of simulation results and combined with TEDs emissions. The plan proposes to prioritize the control of large trucks (diesel), self-use minibuses (gasoline) and four-stroke locomotives in the line source, and achieve the priority control of the line source through the emission reduction of the vehicle type, and then target the point source and the area source. List the industries that require priority control. In point sources, priority should be given to the power supply industry, non-hazardous waste treatment industry, plastic-related manufacturing, and steel-related industries. In terms of non-point source pollution, it is recommended to target ship and commercial emissions and surface coating industry. According to CMAQ, the impact of the power industry is simulated. Regarding the contribution of ozone, regardless of coal-fired and gas-fired power plants, the contribution ratio is the largest contribution ratio in the southwestern half of the coast. Discussion on the trend of changes in air pollutant emissions during the covid-19. The results showed that the NOx emissions of highway vehicles during the city’s three-level alert period were relatively unchanged, while CO and NMHC decreased significantly. This was mainly due to the decrease in the number of small buses and large vehicles. Although there is also a downward trend, in general, the number of small cars has dropped much higher than that of large cars. During the epidemic, the PM2.5 and ozone levels of empty-product test stations increased by 10% and 3% respectively between 2020 and 2021. At the same time, The NOx concentration dropped by 25%, and the maximum total oxidant ozone plus nitrogen dioxide dropped by 1%.