The Characteristics And Temporal Changes Of Hefei Haze

Based on the environmental monitoring data,high-altitude meteorogical data, ground meteorogical data and observations of atmospheric aerosols from 2013 to the first half of 2014 of Hefei, reveals the variation of Hefei’s haze; this paper studied the influence of weather conditions and meteorological elements for the formation of haze; it analyzes the characteristics of atmospheric particulate matter pollution in Hefei during the haze weather; and it also analyzed the meteorological characteristics, local pollution characteristics during a variety of typical haze;at last,on the basis of the above studies and make some suggestions for controlling haze in Hefei. The main conclusions are follows:(1)There are 145 haze days of Hefei in 2013, the haze days accounted for 39.7% of the total number of days a year. January and December were the worst months of the annual haze, they were 26 days and 21 days for haze. According to the statistics, when Hefei happened haze in2013, the ratio of PM2.5/PM10is0.96 to 0.99, the visibility is not more than 3.0km, the atmospheric pressure is about 1023 hPa, the temperature is low, below 5℃, the relative humidity is 73%～81%, the wind speed is 1.5m/s, the rainfall is almost zero.(2)Count August 2013 to February 2014 of PM10, PM2.5 and PM1 synchronized automatic monitoring data, the results are shown:the average ratio of PM2.5 and PM10 was 66.7%, the average ratio of PM1 and PM2.5 was 56%. When it is heavy pollution weather, the value of PM2.5/PM10 will rise, but the value of PM1/PM2.5 will reduce. So pollution is mainly caused by fine particles PM2.5.(3)When in winter, the wind speed will be greater when in 500m altitude, it will be easier to diffuse particulate matter under certain wind speed, but beyond a certain threshold, the winds will increase the role of local granulation, it will increase the concentration of particulate mater near the ground because of turbulence and vertical diffusion, this is likely to cause higher pollution concentrations. From the local pollution, pollution comes mainly from local pollution, industrial emissions, vehicle exhaust, coal combustion and so on, there are also coal-fired delivery from northern city, the straw burning at the end of autumn will bring more biomass burning aerosol mass.In some areas by the end of January 2014 the pollution be aggravated, there are contributions to the discharge of fireworks during the Spring Festival, pollution above 1km comes mainly from the northwest.(4)According to Hefei haze analysis feature and integrate distribution of particulate matter, the current proposal to Hefei haze pollution control should focus on the following two aspects:the first one is to control pollution sub-regional, divide Hefei into three distinct characteristics regional areas according to the east and north of the city, the main city and the other region, focus on industrial waste gas treatment, urban dust, and vehicle exhaust, completed a good remediation work about the sources of pollution sub-regional and classified. The second one is to build ventilation corridors, set ventilation corridors according to the prevailing wind direction in Hefei, open up the city passageway from suburban to urban air, introduce the wind from countryside to main city to increase the air flow of the city.