Pollution Characteristics And Sources Apportionment Of PM_2.5 In Zhenhai District Of Ningbo,China

Sources apportionment of PM_2.5 in air is the basis for prevention and co ntrol of air pollution scientifically and efficiently.Zhenhai District of N ingbo,C hina suffers heavy haze and PM_2.5pollution.So it is necessary to study on the assessment of pollution characteristics and sources apportionment of this area.In this research the Longsai hospital,Environmental Monitor Station,C huang E HUI GU building and Jiulonghu lake were set as the monitoring sites.The samples were analyzed for the PM_2.5 concentration,as well as the elements,TC,TOC,Cl^-,NO₃^-,SO₄^2-,NH₄⁺in PM_2.5.Modification of methods,A good relationship between Beta ray method and light scattering method was found?r=0.973?.The sample strip of automatic sampler should be replaced by propylene membrane which is clean and simple.Particle distribution characteristics,Annual concentrations of PM_2.5 and PM₁₀ are 4.2?g/m3 and 61.3?g/m3 respectively,exceeding Grade 1 of the environment quality standard.Both PM2.5 and PM10 varied with seasons,winter>spring and autumn>summer.The pollution of PM_2.5 on main road is much more heavy,and traffic is positively related to the PM_2.5.PM_2.5 is positively related to PM₁₀,and the proportion of PM_2.5 in PM₁₀ is approximately 77%.The results of apportionment are as follows:The EF factors of Cl,Zn,As are higher than 100,and the EF factors of Pb,Cu,N i,K and Cr higher than 40,which means the elements are influenced by human activities.CMB model shows PM_2.5 is from industry?55.6%⁶2.9%?,dust?19.9%³0.3%?,and vehicles?10.0%¹2.9%?.The[NO₃^-]/[SO₄^2-]is PM_2.5 is between 0.5 and 1,which means it is mainly from stationary source.The SOR in PM_2.5 is generally higher than NOR,which shows that the sulfate and nitrate are mainly secondary particles produced by photochemical reaction.PC A/APCS model shows Na,Co and Si are from sea salt particles;Ca and Ti are mainly from building cement,fuel oil and electroplating pollution source;Co,Si and Zn are mainly from waste incineration and Tire wear.The prevention measures were proposed according to the conclusions of sources apportionment.