Abstract: To investigate exposure characteristics of PM_2.5, a panel study was conducted for elderly subpopulation in Tianjin City, using particulate matter personal exposure monitors. One hundred and one elderly participants (mean age:67) were selected and monitored longitudinally in summer (13^th June-2^nd July) and winter (30^th November-12^th December) of 2011. The results showed that the personal PM_2.5 mass concentrations were (124.2±75.2) μg/m³, (170.8±126.6) μg/m³ for summer and winter, respectively. The result of Spearman correlation analysis showed that concentration of Si (R=0.61), NH₄⁺(R=0.55) and NO₃^-(R=0.46) had significant correlations (P<0.01) with PM2.5 mass concentration. In addition, enrichment factor analysis addressed high concentrations of Cd, Zn and Pb, this indicated that the results were notably affected by anthropogenic sources. The anion SO₄^2- was the most predominant water soluble ions followed by NO₃^- and NH₄⁺. The sum of SO₄^2-, NO₃^-, NH₄⁺ concentration accounting for 40.6%, 34.3% of the PM_2.5 mass concentration in winter and summer, respectively. OC was also the major component of personal PM_2.5 with percentages of 27.4%, 19.3% in winter and summer, respectively. Concentrations of personal PM_2.5 chemical compositions were mainly effected by meteorological factors including indoor and outdoor sources with great seasonal variations. Concentrations of crustal elements including Al, Si,K,Ca and Fe in winter were higher than in summer while concentrations of most trace elements including V,Cr,Mn,Ni,Cu,Zn,As,Sb and Pb appeared reversely higher in summer. ANOVA analysis showed that concentrations of SO₄^2-, NO₃^-, NH₄⁺, OC and EC were significantly higher in winter than those in summer (P<0.05).