Liu B.,Nankai University |
Song N.,Nankai University |
Dai Q.,Nankai University |
Mei R.,Taian Environmental Protection Monitoring Station |
And 3 more authors.
Ambient PM2.5 samples were collected in the urban area of Taian in China in August-September and November, 2014. The chemical compositions and emission sources of PM2.5 were analyzed. The results indicated that the mean concentration of PM2.5 reached 70.8 μg/m3 during the non-heating period, and water soluble inorganic ions (WSIIs), carbonaceous materials, including elemental carbon (EC) and organic carbon (OC); and elements contributed 43.80%, 10.34% and 17.36%, respectively, to PM2.5. The mean concentrations of WSIIs at three sampling sites decreased in the same order: SO4 2->NH4 +>NO3 ->Cl- during the non-heating period. NO3 - and NH4 +, SO4 2- and NH4 +, showed extremely significant positive-correlations (r=0.79, 0.54; P<0.01). The variability of OC was larger than the variability of EC during the non-heating period. The high concentration of secondary organic carbon (SOC) could reduce correlation-level between the OC and EC. Moreover, the percentages and concentrations of the total detected elements (TDE) increased significantly, ranging from August-September to November (P<0.01). Major sources of PM2.5 identified from positive matrix factorization (PMF) model and enrichment factors (EFs) included secondary aerosol, coal combustion, metal manufacturing, soil dust/resuspended dust/construction dust and vehicle exhaust/biomass burning, which contributed 27.47%, 17.94%, 19.06%, 9.41% and 16.65%, respectively, to PM2.5. The backward trajectory analysis identified three transport pathways that originated from Mongolia (12% of the total trajectories), Inner Mongolia (2%), and southeast of Shandong Province (86%), and the potential source contribution function (PSCF) model identified southeast of Shandong Province was mainly a potential source-area that affected air quality in Taian. © 2015 The Authors. Source