隧道大气细颗粒物及其元素的粒径分布特征

Size Distribution Characteristics and Elemental Composition of Airborne Fine Particles inside a Tunnel

对比研究了隧道和大气环境中不同粒径细颗粒物(切割粒径分别为0.03,0.06,0.108,0.17,0.26,0.40,0.65,1.0,1.6和2.5μm)中S,K,Ca,Ti,Mn,Fe,Zn,Pb,Al,Si,Cu和V等12种痕量元素的浓度.结果表明:隧道中不同粒径细颗粒物的数浓度和质量浓度在上下班高峰时段出现明显峰值,且隧道细颗粒物在0.108μm粒径处的数浓度和在2.5μm粒径处的质量浓度分别是大气环境对照值的15.2和40.0倍;在隧道传输过程中质量浓度增加的痕量元素有Si,Ca,Fe,Al,Ti,Zn,Mn,Cu和V,减小的有S,Pb,Zn和K;地壳元素(Si,Ca,Fe,Al和Ti)的质量浓度总和占隧道细颗粒物中痕量元素质量浓度总和的87%,表明土壤扬尘仍是隧道大气细颗粒物的主要来源.

The air quality and pollution characteristics inside tunnels have been receiving more and more attention.Mass concentrations of airborne fine particles with different sizes（cut-off diameter：0.03,0.06,0.108,0.17,0.26,0.40,0.65,1.0,1.6,and 2.5 μm） were compared between inside a tunnel and the ambient atmospheric environment.In addition,the mass concentrations of 12 trace elements（S,K,Ca,Ti,Mn,Fe,Zn,Pb,Al,Si,Cu,and V） in the fine particles were investigated.The results showed that both number and mass concentrations of fine particles with different sizes reached obvious peaks during rush hour inside the tunnel.Moreover,the number concentrations of particles with size range of 0.108 μm inside the tunnel were 15.2 times those in the ambient atmospheric environment.Mass concentrations of particles with size range of 2.5 μm reached 40.0 times those in the atmospheric environment.The trace elements Si,Ca,Fe,Al,Ti,Zn,Mn,Cu and V in the fine particles showed larger mass concentrations inside the tunnel,while S,Pb,Zn and K showed lower mass concentrations.Mass concentrations of the crustal elements such as Si,Ca,Fe,Al and Ti accounted for approximately 87% of the total elemental mass concentration of the fine particles inside the tunnel,indicating that soil dust is still the main source of fine particles in the tunnel.