Modeling And Source Apportionment On Typical Air Pollutants Over Beijing-Tianjin-Hebei Region

To investigate the formation pathway and source contribution of the typical air pollutants, an air quality model(CAMx)is applied in Beijing-Tianjin-Hebei Area in this research paper during the 2014. In the process of simulation, particle source apportionment technology(PSAT) and process analysis (PA) module in beijing-tianjin-hebei region during the heavy pollution of particulate matter sources are analyzed. In this paper,regional source contribution was calculatedusing PSAT. The formation of PM2.5of Beijing during the winter and summer heavy pollution cases was conclude by using two kinds of numerical methods.The main results from this study are as follows:1. Along the Taihang mountain and northern of beijing-tianjin-hebei area, local source contribution is the most regional contribution, with the contribution rate was 70% 80%.Regional contribution of field increases gradually as the distances with geographical position near the provinces. The local contribution rate of Beijing, Tianjin, is accounted for 55%～50%.EasternHebei city pollutant source area are greatly influenced by other provinces. Local contribution of Primary pollutant contribution is the biggest contribution which is rate was 70%～90%.Secondary conversion air pollutants such as sulfate, nitrate, showed obvious characteristics of regional distribution, local contribution rate is ranged from 30% to50%.Seasonal changes of the regional contribution of Secondary Pollutants change more obvious than the Primary Pollutants. Different receptor section of calculating pollutant area source contribution performances varily. Choosing regional average calculation scheme of the foreign contribution ratio is greater than the single point of scheme selection, this diversity of primary pollutant source appointment is more obvious.2. Chemical conversion and horizontal transmission of the variation of PM2.5 during the heavy pollution period has played an important role. During the heavy pollution accumulation phase, chemical formation contributed from 5～40ug/m3 per hour during heavy pollution and horizontal transport contribute 10μg/m3 per hour to the PM2.5 concentration. Chemical generation and horizontal transmission during winter and summer heavy pollution cases display an obviously different contribution of the variation of p(PM2.5). In winter,chemical conversion and horizontal transmission contribute more than 40μg/m3 per hour.Chemical level of generation and transmission of the main contribution of p(PM2.5) is lower than in summer. Outside source contribution during the period of heavy pollution growth has played an important role in its variation of concentration.3. The concentration of PM2.5 near the ground during heavy pollution growth period can reach an 2.5～10 μg/m3 increment in one hour.This changes in winter is significantly greater than the summer. Foreign source where from hebei, shandong region, contribution to the Beijing can reach 35～20 μg/m3 (winter) and 12～17 μg/m3 (summer).With the increasing of the concentration of PM2.5,long-distance of the source region which is contribute to Beijing is gradually increase by 20%.4. During the period of heavy pollution in Beijing, the horizontal wind field maintains west or west south from 700hpa height to 850 hpa height, and south-west winds were maintained from 850hpa height to the ground. With the decreasing of the height, the horizontal wind speed gradually weakened. Wet moisture of water vapor on the absorption of PM2.5 growth has played an important role to the increment of concentration of PM2.5. Some differences appears on the distribution of the vertical layer of meteorological features during the polluted cases in winter and summer. More clearly structure of inversion layer and lower boundary layer height displayed in winter,while wetter vapor condition which helps the chemical conversion of PM2.5 in summer.