| Since the reform and opening-up, the urbanization and industrialization of Xi’an have developed rapidly. However, the air quality of Xi’an is deterioratingand the particulate matter is the primary pollutants. In order to reveal the characteristics and laws of atmospheric particulate concentration change in Guodu town of Xi’an better, which will provide a scientific basis for prevention and control measures of pollution, it is necessary to study the variation and the law of atmospheric particulate concentration in Xi’an.In Chang’an campus of Shaanxi normal university, we observed the PM10concentration and meteorological factors in 52m height range in day and night for three times in October 2013. Our research contains the spatial and temporal variation characteristics, laws and influencing factors of PM10 concentration andevaluation of air quality grade.Draw the following main conclusions:(1) Through diurnal variation observation of PM10 concentration in Guodu Town of Xi’an in 2013 October,found that diurnal variationof PM10 concentration at 4-52m was similar, which totally indicated bimodal distribution, reaching peak at 12:00 and22:00 respectively, reaching minimum at 16:00. The diurnal variation of PM10 concentration is large.According to diurnal variation of PM10 concentration, it can be divided into four stages.(2) According to vertical variation of PM10 concentration, it can be divided into three categories.(3) PM10 concentration was negatively correlated with temperature and wind speed significantly in 2013 October at study area. PM10 concentration was positively correlatedwith relative humidity and air pressure significantly in 2013 October at study area. But correlations are not very significant.The influence of meteorological factors analysis based on neural network showed that the effect of temperature is the largest during the observation, followed by wind speed, air pressure, and relative humidity.(4)During the period of observation, the local source of PM10 mainly comes from the construction dust and vehicle exhaust, main remote source comes from that areas where industrial and mineral industry are developed or the climate is dry, low vegetation coverage rate,and more dust regions.(5)According to the observation data of PM10 concentration in October 2013, using the API method to evaluate the quality of atmospheric environment in Guodu town of Xi’an. The results show that, air quality in observation region in October 2013 is mainly grade III pollution and the primary pollutant is particulate matter.The pollution of particulate matter is serious and air quality in Guodu town of Xi’an is bad.(6)Using the multiple regression model and neural network model to forecast PMio concentration respectively, the results show that while the two models can better response vertical changes of PM10 concentration, but the neural network model is better to predict vertical variation of PM10 concentration.(7)The atmospheric environment quality of Xi’an is deteriorating in recent years, so it’s in pressing need of improvement and renovation. Thus we should introduce advanced biological membrane dust suppression technology, micron grade dry fog dust suppression technology, wet dust collecting technology and so on, to reduce pollutant sources,and improve the air quality of Xi’an. |
PDF Full Text Request