Pollution Characteristics Of Atmospheric Particulate Matter And Health Risk Assessment In A University,Hengyang

This paper take the Hongxiang district of University of South China as the research object. The sampling points of total suspended particles?TSP? and fine particles(PM_2.5) in campus are located in the roof of a school building in university of south China. TSP and PM_2.5 samples are collected in 2014 winter and 2015 spring, summer,autumn respectively.The seasonal variation of the mass concentration of TSP and PM_2.5, heavy metal content and the major water-soluble ions pollution is analyzed. Health risk assessment of heavy metals in PM_2.5 is carried out. In addition, the characteristics of particle size distribution in2015 winter in the four functional areas including commercial area, living area, traffic areas and industrial zones in the outside of school is studied.The main results are as follows:?1? The order of campus TSP average concentration in winter,spring, summer and autumn is 380.7 m/g m³ ?157.8 m/g m³ ?100.1 m/g m³ ?331.3 m/g m³ ? Winter and autumn are beyond the secondary standard concentration limits specified 300 m/g m³ of "Ambient Air QualityStandard"?GB3095-2012?. The order of campus PM_2.5 average concentration in winter, spring, summer and autumn is 179.5 m/g m³ ?80.8 m/g m³ ?46.8 m/g m³ ?161.2 m/g m³ ?Winter, spring and autumn are beyond the secondary standard concentration limits specified 75 m/g m³ of Ambient Air Quality Standard?GB3095-2012?.?2? In campus TSP and PM_2.5,the order of the annual mean concentration of heavy metals?Fe, Pb, Cu, Cr, Ni, Cd? is: Fe> Pb> Cu>Ni> Cr> Cd. The content ratio(PM_2.5/TSP)in all the heavy metals was higher than the mass content ratio(PM_2.5/TSP)in atmospheric particulate matter. Heavy metals were easier concentrate in fine particulate matter.?3? In campus TSP and PM_2.5,the total potential ecological risk degree reaches terribly strong and PM_2.5>TSP. The order of potential ecological risk index of heavy metals is Cd>Cr>Pb>Cu>Ni. The potential ecological risk degree of Pb,Cd and Cr reaches terribly strong.?4? The enrichment factor method results show that in campus TSP and PM_2.5, the enrichment strength of heavy metals in PM_2.5 is greater. In winter and spring,the order of enrichment degree of heavy metals is Cd>Cr>Pb>Cu>Ni. In summer and autumn,the order of enrichment degree of heavy metals is Cd>Cr>Cu>Pb>Ni. The EF of Heavy Metals is more than one. It indicates that the relative enrichment of the heavy metals are influenced by human activities.?5? In campus PM_2.5, heavy metal elements in the average annualexcess risk of the exposed population by respiratory pathway is Pb>Cu>Ni>Cr>Cd. Three kind of cancer-causing heavy metals?Cd,Cr,Ni?leads to that the lifetime incremental cancer risk of three groups is more than the acceptable risk level of 10^-6 / year. There is a potential cancer risk. The integrated non-carcinogenic risk index of two kinds of non-carcinogenic heavy metal elements?Pb,Cu? is less than the acceptable upper limit 1 of the body. It indicates that non-cancer risk at an acceptable range.?6? In campus TSP and PM_2.5, The order of concentration of Water-soluble ions(SO₄^2-,NH₄⁺,NO₃^-) is SO₄^2->NH₄⁺>NO₃^-. Seasonal variation is: winter> spring> autumn> summer. The annual average ratio of NO₃^-/SO₄^2- in TSP and PM_2.5 is 0.317 and 0.329. It shows that the stationary sources?such as coal-fired? is the main. It has shown a good correlation between the water-soluble ions in TSP and PM_2.5 samples. It shows that the source of water-soluble ions is similar.?7? The order of total number of atmospheric particulate matter outside campus in four functional areas is: industrial area> traffic>business district> living area.The order of total surface area of particles in four functional areas is: industrial area> traffic> business district> living area. The size of total mass concentration of particles in four functional areas is: industrial area>traffic> living area> business district.The mass concentrations of PM_2.5 and PM₁₀ in outside campus of the four functionalareas exceed the national standard limit in the air control. The ratio of concentrations of PM_2.5 and PM₁₀ in four functional areas is more than50%. The highest ratio reached 93.2%. It indicates that respirable particulate matter is mainly fine particles.