What are the main causes of air pollution in Baoji? Measures to eliminate (or reduce) pollution

① The frequency of static wind in the near-surface layer of Baoji City is high, and due to the narrow terrain, the annual average wind speed is only 1.2 meters/second, which is not conducive to the diffusion of air pollutants, but the diffusion conditions in the middle and upper atmosphere are better. ②The wind direction and wind speed of the atmospheric boundary layer in Baoji urban area vary greatly from day to day, and the valley wind circulation characteristics are obvious. The wind speed changes greatly vertically, the wind shear ranges from 200 to 500 meters, and the atmospheric diffusion capacity is higher than that of Xianyang and Xi'an. ③The mixed layer in Baoji City is relatively high, and the ventilation volume is about 30% greater than that in surrounding areas, which is conducive to the outward diffusion of air pollutants above the middle layer. ④The near-surface wind shear field in Baoji urban area is located in the "Qianwei Meeting" area. The wind direction and wind speed shear in this area are large, and the flow field differences are obvious. The quiet wind frequency in the area east of Wolong Temple is 22%, which is about 30% smaller than that in the urban area. The annual average wind speed is 2.2 meters/second, which is 1 meter/second higher than that in the city center. ⑤Baoji City has a large annual rainfall and a good surrounding ecological environment, which has a significant effect on rain washing and ecological purification of air pollutants. ⑥The special terrain and meteorological conditions of Baoji urban area make the average life span and half-life of air pollutants shorter. ⑦ When the stationary peak of the Qinling Mountains occurs and the northeasterly wind blows in during the winter half of the year, it is easy to cause aggravation of urban air pollution. This is mainly caused by weather systems. ⑧The environmental capacity after SO2 and NO2 reduction in urban areas of Baoji City calculated by the multivariate model only accounts for 53.8% and 65.7% of the ideal environmental capacity of urban SO2 and NO2 respectively, so the remaining atmospheric environmental capacity is relatively large. ⑨ As the current emission sources (industry and transportation) account for a small proportion of respirable particulate matter PM10 in urban areas, the main reasons for exceeding the standard are ground dust, secondary particles and external input. ⑩ Judging from the accounting results, the air pollution sources from Baoji No. 2 Power Plant and Guozhen Industrial Zone have relatively little impact on urban Baoji City. From the above conclusion, it can be seen that Baoji City still has relatively large space for economic development, regardless of meteorological conditions or atmospheric environmental capacity. Main suggestions: ① Urban planning and industrial layout should fully consider the meteorological conditions of Baoji and follow the transport and diffusion laws of air pollutants. ②The future industrial layout of Baoji urban area should expand from the east of Qianhe River to the east. ③The emission height of air pollution emission point sources of newly built enterprises should be increased, and their effective emission height should be above 75 meters, which is conducive to the rapid diffusion of air pollutants. ④Baoyuan Thermal Power Company (formerly Baoji Power Plant) is the largest point source of air pollution in the city. After the company's dust collector was modified in 2004, its annual PM10 emissions were 70.7 tons. A decrease of 5830 tons compared with 2002. However, the annual emissions of SO2 and NO2 still account for 72% of the total urban point source emissions. The company should speed up the management of SO2 and NO2. ⑤The air quality in the northern plateau of the urban area (Lingyuan and Panlongyuan) is good, which is conducive to the diffusion of atmospheric pollutants and is suitable for building residential areas. ⑥In terms of utilization of remaining atmospheric environmental capacity, more new enterprises with low resource consumption, high technological content and low environmental pollution should be developed, and heavy polluting enterprises are strictly prohibited from entering urban areas. ⑦The environmental management department should speed up the implementation of the reduction plan, rationally utilize the existing atmospheric environment capacity resources, and accelerate the sustainable development of Baoji City.