Pollution Sources And Correlation With Meteorological Conditions Of Heavy Air Pollution Process In Zibo City

The problem of air pollution in Zibo city is serious in recent years,the main difficulties to control air pollution in the region is research of percentage of contribution of different sources to air pollution and local and regional meteorological conditions’ mode and degree of influence on the process of heavy air pollution in Zibo city is not enough.In this paper,the data of air quality,meteorological conditions and air pollutant emission of Zibo city in 2015 was obtained through field investigation,data statistics and research other data,and this paper selects typical heavy air pollution process,determines the list of main atmospheric pollutants’ resources and input the list to RAMS-CMAQ model,then uses the model to achieve numerical simulation of the typical heavy pollution process to get the resource of heavy air pollution process,and analyzes the correlation of heavy pollution and meteorological conditions.Results of this paper are listed as following:(1)Sources of pollution in Zibo city:(1)Analyze from all the processes,except process 3(March 27 th to April 6th)was caused by the explosive increasing of PM10 due to the sandstorm weather,other processes were mainly caused by secondary pollution of PM2.5 which was mainly caused by secondary conversion,sulfate’s contribution on secondary pollution is the largest(above 40%),followed by nitrate(about 18%),then organic carbon,ammonium(both about 15%).Under sandstorm weather,contribution of coarse to PM2.5 was above 18%,in other conditions,contribution of coarse and BC were both about 10%.When the contribution of sulfate concentration was large and SO2 was clearly higher,heavy pollution mainly came from the accumulation of local emissions,besides,when the distribution of nitrate and sulfate were close and the concentration of NO2 was low,heavy pollution mainly came from regional transportation.(2)Analyze from the winter(January)characteristics pollution,except nitrate,contribution of local sources to air pollution in winter of Zibo city was above 80%,which of regional transpotation was about 20%,and regional transpotation of nitrate was above 40%.Among local sources,industrial was the most important,which contribution was above 40%,civil,electric power also had clear contribution,which percentage were both about 15%.Contribution of agriculture,dust and mobile was little.(2)Correlations between air pollution and meteorological conditions in Zibo city(1)Influence of wind speed and mixed layer height(MLH)on the air quality was much clearer than other meteorological conditions,a large number of pollutants accumulation and the occurrence of heavy pollution were easily occurred under a local or regional low wind speed(wind speed was less than 2.0m/s)or static wind weather,while average MLH was less than 200 m,and heavy pollution continued longer or even worse when this type of weather lasted longer.According to the geographical location of Zibo city,when the local or regional wind direction is northwest or northeast and the wind speed is high,the pollutants were easy to diffuse.(2)The effect of relative humidity(RH)on air quality is clear,a large number of pollutants accumulation occurred when local or regional humidity was high(RH was greater than 70%),but when humidity was high enough to form water-vapor saturation,pollution would reduce due to rainfall.(3)Cold(worm)front could be observed from local air temperature(TA)and pressure(PRES),there would be a cold(worm)front to transit when TA became lower(higher)and PRES became higher(lower),and the speed of the frontal surface was fast(slow)when the range of change of TA,PRES was great(small).Air quality would be better after a transition of a cold front.The relationship between temperature stratification and the air quality was clear,when the temperature inversion occurred at the heiight of 150~250m and the thickness was greater than 100 m,the duration was longer than 24 h,a large number of pollutants accumulation would occur.Analyze from the regional pressure field,uniform pressure field and regional sparse isobars is an important cause of accumulation of pollutants and the occurrence of heavy air pollution.(4)Lifted index can be used to characterize the atmospheric stability,and the relative decrease of the atmospheric stability was beneficial to the diffusion of the pollutants when Lifted index became smaller.