Study On The Relationship Of Air Quality And Meteorological Conditions In Changsha

With the acceleration of urbanization and the rapid development of economy and society in Changsha,the environmental air pollution problem,which is mainly caused by PM_2.5,PM₁₀,O₃,CO,NO₂ and SO₂,is becoming more and more obvious.Ambient air pollution not only affects the quality of life and happiness of urban residents in Changsha,but also has a negative impact on the sustainable development of the economy and society.Under the high pressure of controlling air emission and air pollution posed by the government,it is very necessary to strengthen the analysis and research on solving the environmental air quality problems in Changsha from both engineering and non-engineering measures.In this paper,from a perspective of non-engineering prevention and control of air pollution,based on the theory of environmental meteorology and synoptic science and statistics from meteorological observation and environmental monitoring,an analysis of the temporal and spatial changes of air quality in Changsha urban area in recent years has been conducted daily,seasonally,yearly and regionally.Also,emphasizing on the relationship of ambient air quality and meteorological conditions,meteorological conditions that affect air quality,and forecasting approaches and its discriminant index have been discussed and analyzed as well as the application of new meteorological observation data and numerical simulation in air quality forecast,from the aspects of the variation of meteorological elements,the characteristics of weather and atmospheric boundary layer respectively.The main conclusions are as follows:in recent years,air quality control in Changsha urban area has been conducted effectively,and the appearance of primary and main pollutant's AQI and IAQI has showed a downward trend,but the concentration of O₃ pollution has arisen.The ambient air quality in summer is better compared to which in winter,autumn and spring.The ambient air quality in winter is the worst.The meteorological conditions have great influence on the ambient air quality in Changsha urban area.According to the meteorological elements,on average,the air quality of Changsha urban area is closely related to air temperature and air pressure.The air quality is relatively good when there's low air pressure or high air temperature,and vice versa.According to the average field of high altitude weather situation analysis and calculation,a conceptual model of heavy pollution meteorology has been established in autumn and winter,when the air pollution is relatively severe.During the two seasons,the circulation at 500hPa is flat and zonal,and the westerly wind is obvious when the air pollution occurs;and the high pressure circulation is in control of 700hPa in autumn,while in winter the influence of the relatively strong southwest airflow is obvious;850hPa is controlled by the northwest airflow ed the high pressure circulation in autumn,while in winter it is the intersection of the weak southerly airflow and the northerly airflow;and humidity is low at 700/850hPa when the air pollution occurs in autumn and winter.In terms of the characteristics of boundary layer,air quality in Changsha showed a close correlation to the height of mixed layer and ventilation,and there is a general negative correlation between height of mixed layer and air pollution index in Changsha.In addition,it is proved that the static weather index,numerical simulation and the newly-built wind profile radar in Changsha can be applied to the operational services of environmental meteorology.