Situation And Spatial-temporal Characteristics Of Atmospheric Particulate Pollution In Taian City

In recent years,Taian has been faced with more serious air pollution problems,especially in winter when smog occurs frequently.The main pollutant indexes PM_2.5.5 and PM₁₀0 have consistently exceeded the national environmental air quality level 2 standard,and the improvement rate of air quality is lower than the middle reaches of 17 cities in Shandong province.The research on the urban air environment pollution,spatial-temporal variation characteristics and rules of pollutants has a significant effect on the air quality forecast,searching for the source of air pollutants,air pollution control and the research of the air pollution characteristics in the third and fourth-tier cities and county-level administrative regions.This paper analyzed the hourly concentration of PM_2.5.5 and PM₁₀0 in the air from 0:00 on January 1,2013 to 23:00 on February 28,which was released by Shandong Province Environmental Information and Monitoring Center.The monitored includes seven stations in Taian（Houfeng Inc.,Population School,Taishan Monitoring Station,Jiaotong Technical School,New Campus of Shandong Agriculture University,Shandong Electric Power School,ICT Technology）and eight county monitoring stations（Xintai Meteorological Bureau,Xintai Xinwen,Feicheng Environmental Protection Bureau,Feicheng Justice Bureau,Ningyang Experimental Middle School,Ningyang Vocational Education Center,Dongping Monitoring Station,Dongping Park Management Committee）.With the single project evaluation method,this paper evaluated environmental quality level in Taian from 2013 to 2017,studied the spatial-temporal variation characteristics of PM_2.5.5 and PM₁₀0 in the environment in 2017.The results showed that:（1）The present situation of the air pollution in TaianThe yearly mean of PM_2.5.5 and PM₁₀0 decreases annually from 2013 to 2017,within the range of 56μg/m3⁹1μg/m3and 103μg/m3¹52μg/m3;they were both the highest in 2013,91μg/m3and 152μg/m3respectively.Whereas they were the lowest in 2017,56μg/m3and103μg/m3respectively.They all exceeded the second-level standard of Environment Air Quality（GB 3095-2012）.The pollution of PM_2.5.5 and PM₁₀0 in the air was comparatively serious in Taian.The yearly mean of PM_2.5.5 and PM₁₀0 were both the highest in Dongping among all the counties in Taian,60μg/m3and 115μg/m3respectively;and they were the lowest in Daiyue District,48μg/m3and 92μg/m3respectively.The average PM_2.5.5 concentration from high to low is in Dongping county>in Ningyang county>High-tech zone>in Taishan district>in Feicheng city>in Xintai city>Daiyue district.The average annual concentration of PM₁₀from high to low is high-tech zone>Dongping county>Xintai city>Ningyang county>Feicheng city>Taishan district>Daiyue district.The highest concentration of PM_2.5.5 was in December in Ningyang,whereas in January for other districts.The lowest concentration of it was in September in Ningyang and Xintai,whereas in August for others.For all,the highest concentration of PM₁₀0 was in January;as for the lowest,it was in September and October in Xintai,in October in Feicheng and in August in the rest districts.（2）Hourly variation trendFrom the perspective of time-by-time change,the overall average concentration of PM_2.5and PM₁₀0 in 2017 is in winter>in autumn>in spring and summer in turn.And they were higher than the daily mean of the national standard during the whole day in Winter.They appeared unimodal type in summer and bimodal type in the other three seasons.The peak value of bimodal type was generally from 8:00 to 10:00 and 20:00 to 23:00,while the valley value was from 14:00 to 16:00.From the monthly changes,the maximum concentrations of PM_2.5.5 and PM₁₀0 were in January microns,which were 96.25μg/m3and167.39μg/m3,respectively.The lowest months were August,29.20μg/m3and 59.38μg/m3respectively.The whole year showed the trend of“U”shape,decreasing first and then increasing.In terms of seasonal changes,PM_2.5.5 and PM₁₀0 concentrations were both the highest in winter and significantly higher than in other seasons,and the lowest in summer.From the range of changes,PM_2.5.5 changed the most in Autumn and PM₁₀0 changed the most in winter.（3）Spatial variation featureIn 2017,the annual PM_2.5.5 concentration at 15 monitoring stations exceeded the national second-level standards,the highest of which was power schools,63.13μg/m3,0.80 times higher than the standard.The lowest is the Xintai Meteorological Bureau,36.85μg/m3,0.05times over the standard.The largest daily difference of PM_2.5.5 is at Dongping Monitoring Station and the smallest at Xintai Meteorological Bureau.In terms of the daily standard reaching rate of the whole year,the highest is Xintai Xinwen（88.22%）,and the lowest is Ningyang Experimental Middle School（71.79%）.Except for the Feicheng Justice Bureau in summer,the monitoring site with the highest seasonal average concentration of PM_2.5.5 was Xintai Xinwen in the other three seasons.In 2017,the average annual concentration of PM₁₀0 at 15 monitoring points exceeded the national second-level standards,the highest of which was the new campus ofagriculture university,139.98μg/m3,1.00 times higher than the standard.The lowest is the Population School,85.27μg/m3,0.22 times higher than the standard.The largest day difference of PM₁₀was the in Xintai Meteorological Bureau,the smallest is in Feicheng Environmental Protection Bureau.In terms of the daily standard reaching rate of the whole year,the highest is Population School（93.42%）,and the lowest is ICT Technology（77.80%）.PM₁₀0 season average concentration of the highest monitoring point in spring and winter are Houfeng Inc.,summer is Dongping Monitoring Station,autumn is Ningyang Vocational Education Center.（4）Variation characteristics of the ratio between particlesFrom the monthly changes of the ratio of PM_2.5/PM₁₀0 in 2017,PM₁₀0 was the main pollutant from April to September in the city,and PM_2.5.5 was the main pollutant in the rest months.According to the seasonal ratio change of PM_2.5/PM₁₀,PM₁₀0 was the main pollutant in summer and autumn,and PM_2.5.5 was the main pollutant in spring and winter.